RARE DISEASE
Myeloid/lymphoid neoplasms associated with eosinophilia and abnormality of PDGFRA, PDGFRB, FGFR1 or JAK2
Myeloid/lymphoid neoplasms associated with eosinophilia and abnormality of PDGFRA, PDGFRB, FGFR1 or JAK2
Myeloid/lymphoid neoplasms associated with eosinophilia and abnormality of PDGFRA, PDGFRB, FGFR1 or JAK2
Drug discovery
2
drugs
With orphan designations
Overview
Myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene rearrangements (PDGFRA, PDGFRB, FGFR1, or JAK2) are rare, aggressive hematologic malignancies presenting as chronic eosinophilic leukemia, acute leukemias, or lymphomas. They arise from fusion genes causing constitutive tyrosine kinase activation, leading to eosinophil-driven organ damage and rapid progression without treatment [1][2][7][11].
Categories: rare hematological diseases, rare neoplastic diseases, rare transplant-related disorders
Research Papers
1,020 drug discovery papers about Myeloid/lymphoid neoplasms associated with eosinophilia and abnormality of PDGFRA, PDGFRB, FGFR1 or JAK2, with 1 first-in-class and 5 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
1,020 drug discovery papers about Myeloid/lymphoid neoplasms associated with eosinophilia and abnormality of PDGFRA, PDGFRB, FGFR1 or JAK2, with 1 first-in-class and 5 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-08-14 | Identification of Novel Small-Molecule Janus Kinase 1 and 2 Inhibitors Through Structure-Based Virtual Screening, In Vitro Assays, and Molecular Dynamics Simulations.
Janus kinases (JAKs) are central mediators of cytokine-driven signal transducer and activator of transcription (STAT) signaling, and dysregulation of the JAK-STAT axis is implicated in inflammatory, autoimmune, and neoplastic diseases. To identify new small-molecule inhibitors of Janus kinase 1 (JAK1) and Janus kinase 2 (JAK2), we implemented an integrated virtual screening workflow combining structure-based docking and ligand-based prioritization using the InterBioScreen (IBS) compound library. A drug-likeness filter reduced 521,627 IBS molecules to 116,064 candidates, which were then docked into the ATP-binding sites of JAK1 (PDB ID: 4EI4) and JAK2 (PDB ID: 6VGL) using Glide SP; compounds were prioritized using docking score thresholds of <- 8.5 kcal/mol (JAK1) and <- 9.0 kcal/mol (JAK2), yielding 407 JAK1- and 298 JAK2-focused hits. Subsequent analysis shortlisted 42 candidates for enzymatic evaluation. In vitro kinase assays identified multiple nanomolar inhibitors, including compound 1-3 (IC50 = 0.032 μM) among the most potent for JAK1 and compound 2-8 (IC50 = 0.026 μM) for JAK2. Finally, 100 ns molecular dynamics (MD) simulations supported stable binding for representative complexes, with persistent hinge-region interactions for compound 1-3 in JAK1 (e.g., Glu957/Leu959) and compound 2-8 in JAK2 (e.g., Glu930/Leu932), consistent with a stable interaction network in the active site. Collectively, these results define validated IBS-derived hit scaffolds for further optimization and selectivity profiling toward JAK-targeted therapeutics.
2026-07-14 | Uncompetitive Allosteric Inhibition of PTP1B by BP-1-102 Reveals a Potential Dual-Target Strategy toward the PTP1B-STAT3 Oncogenic Axis: Biochemical and Computational Evidence.
Selective PTP1B inhibitors paradoxically potentiate oncogenic STAT3 signaling by restoring JAK2 activity, underscoring the need for dual-target strategies. Here we report that BP-1-102, an orally bioavailable STAT3 SH2 domain inhibitor, also potently inhibits PTP1B with IC50 values of 5.32 μM (hPTP1B1-400) and 11.7 μM (hPTP1B1-285), with ≥37.7-fold selectivity over TCPTP. Kinetic analysis identified an uncompetitive mechanism, suggesting inhibitor binding to the enzyme-substrate complex at a site distal to the active site. Docking and 500 ns molecular dynamics simulations revealed a dual-anchor binding mode involving the 113-123 loop (Cys121) and the proline-rich C-terminal disordered region, a structural interface absent in TCPTP. Umbrella sampling confirmed favorable passive membrane permeability through a tumor-mimetic bilayer (ΔG = -13.83 kcal/mol). These results propose BP-1-102 as a candidate for dual-function inhibitor of the PTP1B-JAK2-STAT3 oncogenic axis, providing a physicochemical and mechanistic rationale for its further evaluation in tumors where both targets are coactivated.
2026-07-14 | Design, synthesis, and activity study of heterocyclic derivatives as JAK inhibitors.
The Janus kinase (JAK) family plays a central role in regulating inflammation and fibrosis through the JAK/STAT signaling pathway, making it an attractive therapeutic target for immune-mediated diseases. In the present study, structural modifications of the quinazoline core were systematically explored to identify potent JAK inhibitors. A CXCL10-based screening strategy identified compound 22a as a promising lead, exhibiting strong inhibitory activity in HaCaT cells with an IC50 value of 308 nM. Subsequent kinase assays demonstrated that compound 22a exhibits higher inhibitory potency toward JAK1 (IC50 = 37.86 nM) compared to JAK2 (IC50 = 102.5 nM), JAK3 (IC50 = 69.35 nM), and TYK2 (IC50 = 2142 nM). Mechanistic studies revealed a dose-dependent suppression of STAT1 phosphorylation, confirming inhibition of the JAK1/2-STAT1 signaling pathway. In addition, molecular docking and molecular dynamics simulations were performed to elucidate and validate the binding mode of compound 22a within the JAK1 active site. Collectively, these results indicate that the developed quinazoline derivatives represent promising leads for the further development of selective JAK1 inhibitors.
2026-07-07 | Janus kinase 2 activation loop as a regulator of catalysis and trans-activation.
Protein kinases regulate essential cellular processes such as apoptosis, proliferation, and growth. Precise regulation of kinase activity is critical for proper signal transduction and is often mediated by activation-loop phosphorylation. Janus kinases (JAKs) employ a unique regulatory mechanism: they remain autoinhibited by their pseudokinase domains until cytokine stimulation triggers dimerization and trans-phosphorylation of two activation-loop tyrosines. Despite its relevance for JAK inhibitor design, the molecular mechanism of JAK activation by activation-loop phosphorylation is not fully understood. Here, we show that phosphorylation of the JAK2 activation loop is essential for stabilizing substrate binding and in the absence of phosphorylation, the activation loop fails to bind substrates. Our findings reveal a unique regulatory role for the activation loop in JAK2, where phosphorylation enhances loop stability rather than inducing a major conformational change as in most protein kinases. In addition, the flexibility of the unphosphorylated activation loop allows conformational changes required for trans-phosphorylation during JAK activation. These insights provide a mechanistic basis for JAK activation and offer new insights for the development of JAK inhibitors.
2026-07-03 | ARHGEF2::JAK2 Fusion Drives Leukemogenesis via CCNB1-Dependent Signaling.
Leukemia is a heterogeneous malignancy with poor outcomes in refractory cases, and fusion genes involving JAK2 are known oncogenic drivers. The ARHGEF2::JAK2 fusion gene combines hyperactive kinase signaling with cytoskeletal regulation, but its functional role in leukemia remains unclear. This study aimed to characterize the oncogenic mechanisms of ARHGEF2::JAK2 and identify key downstream targets. Ba/F3 cells transduced with ARHGEF2::JAK2 and mouse xenograft models were used to assess proliferation, apoptosis, and leukemogenic potential. RNA sequencing, qPCR, and Western blotting were used to analyze downstream targets, followed by functional validation via shRNA knockdown. Results showed that ARHGEF2::JAK2 conferred cytokine-independent growth, suppressed apoptosis, and drove aggressive leukemia in mice. Ruxolitinib ameliorates ARHGEF2::JAK2-induced leukemogenesis in vivo. Transcriptomic analysis identified CCNB1 as a critical downstream effector, and its knockdown reversed the oncogenic effects of ARHGEF2::JAK2, improving survival and reducing organ infiltration. These findings demonstrate that ARHGEF2::JAK2 promotes leukemogenesis via CCNB1 upregulation, suggesting CCNB1 as a potential therapeutic target. This study provides new insights into fusion-driven leukemia pathogenesis.
proteins
2026-08-08 | Hierarchical mathematical modelling of patients with myeloproliferative neoplasms captures interferon-α treatment responses and allows for personalised and population predictions.
The Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) are a group of haematological malignancies triggered by a driver mutation, most commonly the JAK2 V617F mutation, which is acquired in a haematopoietic stem cell. The diseases are characterised by an overproduction of myeloid cells and may result in severe complications such as thrombosis, myelofibrotic transition, and potentially progression to acute myeloid leukaemia. Treatment with interferon-α (IFN-α) can potentially deplete the disease-driving malignant stem cell population, thereby leading to long-term remission. We extend a mechanistic compartmental differential equation model of MPN progression to account for the effects of IFN-α treatment. In agreement with experimental mouse studies, we assume that IFN-α acts through effects on malignant stem cell differentiation and malignant progenitor and precursor cell apoptosis. We use a hierarchical Bayesian inference procedure to infer the drug response parameters of the model based on measurements of the JAK2 V617F variant allele frequency (VAF) for N=56 patients from the Danish DALIAH study, both on the individual and the population level, with 14 patients left out for subsequent testing. The model estimates are found to agree with data. The drug response parameters are found to act synergistically on the reduction of JAK2 VAF, with the model being able to capture qualitatively different types of treatment responses. Using the inferred information about the population distribution of drug response parameters is found to improve predictions compared to predictions without prior knowledge on a testing cohort. Such predictions may aid clinical decision-making regarding IFN-α treatment in patients with MPNs.
2026-06-26 | A Hidden Driver Mutation in Myeloproliferative Neoplasms: SH2B3 and Diagnostic Implications and Response to Ropeginterferon Alfa-2b.
Myeloproliferative neoplasms (MPNs) are commonly linked to driver mutations in the JAK2, MPL, and CALR genes. In contrast, SH2B3 (LNK) mutations are uncommon and remain an under-characterized contributor to dysregulated JAK-STAT signaling. The clinical features and treatment responsiveness of SH2B3-mutated MPNs are not well defined, and data on outcomes with ropeginterferon alfa-2b in this molecular subgroup are limited. We report a 75-year-old man who presented for evaluation of headache, generalized bone pain, and night sweats and was found to have abnormal blood counts including persistent leukocytosis, erythrocytosis, and thrombocytosis. Prior molecular testing was negative for JAK2, MPL, and CALR mutations. Bone marrow examination showed hypercellularity with panmyelosis, mild megakaryocytic atypia, and WHO grade 1 reticulin fibrosis. Hematologic next-generation sequencing identified a pathogenic SH2B3 c.1481C>G (p.Ser494*) nonsense mutation, predicted to result in a loss of SH2B3's C-terminal regulatory domain. Given the tri-lineage cytoses and marrow findings, a diagnosis of SH2B3-mutated MPN was established. He was started on ropeginterferon alfa-2b, resulting in resolution of his symptoms and complete hematologic response (WBC ≤ 10 × 103/μL, Hct ≤ 45%, and PLT ≤ 400 × 103/μL) within 12 weeks, without the need for phlebotomy or treatment-limiting adverse effects. This case underscores the clinical significance of SH2B3 mutations as a driver of triple-negative MPNs and supports their inclusion in molecular evaluation when classical mutations are absent. The favorable clinical and hematologic response to ropeginterferon alfa-2b suggests that interferon-based therapy may be effective in SH2B3-mutated MPNs.
2026-06-11 | Synergistic cooperation between progranulin and Jak2/Stat3 signaling determines definitive myeloid cell fate.
Perturbations in cell fate disrupt tissue homeostasis and drive diseases such as cancer. The JAK/STAT pathway is central to hematopoietic malignancies, yet its regulators in cell fate decisions remain poorly defined. Here, we identify progranulin (GRN) as a critical determinant of myeloid fate through the regulation of JAK2/STAT3 signaling. Using inducible stat3 and grna zebrafish models, knockout approaches, FACS, transcriptomics, and CUT&RUN, we show that Stat3 induces grna, which in turn amplifies stat3 expression, reinforcing myeloid over erythroid commitment. Lineage tracing and live imaging reveal that this Grna/Stat3 feedback operates during definitive, but not primitive, myelopoiesis. Functionally, definitive myeloid cells drive tissue repair, whereas primitive counterparts are less effective. Myeloid differentiation in a human leukemia line required GRN co-stimulation of JAK2/STAT3, highlighting its conserved role in fate determination. These findings uncover a regulatory axis controlling hematopoietic commitment and identify GRN as a potential therapeutic target in diseases with aberrant JAK2/STAT3 activation.
2026-01-16 | IFNα2b modulates anti-tumor immune responses involving STAT3-associated dendritic cell dysfunction in JAK2v617f-positive myeloproliferative neoplasms.
To define JAK2v617f-induced immune alterations, focusing on STAT3-mediated dendritic cell dysfunction, and evaluate whether IFNα2b restores anti-tumor immunity in JAK2v617f-positive myeloproliferative neoplasms. Integrated flow cytometry and single-cell RNA sequencing profiled immune landscapes and signaling pathways, while functional assays assessed dendritic cell differentiation, T cell activation, and IFNα2b-mediated immune restoration. JAK2v617f was associated with increased STAT3 activation in myeloid cells, accompanied by elevated expression of immunosuppressive mediators such as FGL2, impaired monocyte-to-DC differentiation, reduced cDC1/cDC2 subsets, and diminished T cell activation, consistent with an immunosuppressive immune landscape. IFNα2b treatment was associated with attenuation of STAT3/FGL2 signaling and partial restoration of DC-mediated T cell priming, with more pronounced immunomodulatory effects observed in JAK2v617f-positive myeloproliferative neoplasms compared with other subtypes. Our findings indicate that JAK2v617f is associated with STAT3-dependent dendritic cell dysfunction that contributes to an immunosuppressive milieu. IFNα2b modulates this pathway and partially restores DC-T cell interactions, highlighting its potential as an immunomodulatory strategy in JAK2v617f-positive myeloproliferative neoplasms.
2026-01-10 | Real-World Retrospective Report on the Efficacy, Tolerability, and Molecular Responses to Ropeginterferon-α2b in Patients with Myeloproliferative Neoplasms.
Background: Ropeginterferon alfa-2b (Ropeg-IFNa) is increasingly used in myeloproliferative neoplasms (MPN), particularly polycythemia vera, but real-world data across subtypes are limited. We evaluated clinical and molecular responses to Ropeg-IFNa in routine practice. Methods: We retrospectively analyzed 20 JAK2V617F-positive MPN patients treated at a tertiary center. Baseline features, dosing, treatment line, hematologic responses, adverse events, and serial JAK2V617F variant allele frequency (VAF) were extracted from records. Results: Median age at initiation was 53 years; 55% were ELN high-risk. Ropeg-IFNa was started first-line or after peginterferon alfa-2a, hydroxyurea, or a tapered JAK2 inhibitor. Mean treatment duration was 14 ± 11 months at 195 ± 143 µg Q2W. Hematologic control increased from 45% at the start to 60% at the last follow-up. Among patients with serial molecular monitoring (n = 11), median JAK2V617F VAF declined from 21.2 to 12.7%. Ropeg-IFNa was generally well tolerated; adverse effects were mostly manageable, although 3/20 (15%) discontinued due to side effects, including mood disturbances, while others continued with supportive care and dose adjustments. Conclusions: In this single-center cohort, Ropeg-IFNa was tolerable and associated with improved hematologic control and modest VAF reductions, supporting its use in multi-subtype MPN cohorts. These findings underscore the value of longitudinal driver-mutation monitoring during therapy.
antibodies
2026-06-28 | Beyond the JAK2 mutation: The inflammasome, clonal stability, and the thrombotic niche in myeloproliferative neoplasms.
Philadelphia-negative myeloproliferative neoplasms (MPNs) carry a disproportionate thrombotic burden that cannot be explained by conventional cardiovascular risk factors or blood count parameters alone. This review synthesizes emerging evidence positioning MPN-associated thrombosis as a distinct pathobiologic entity, clonal thrombo-inflammation, driven by the convergence of somatic mutations and innate immune activation. We examine the continuum from clonal hematopoiesis of indeterminate potential (CHIP) to overt MPN, highlighting how Janus kinase 2 (JAK2)V617F and other driver mutations reprogram myeloid cells toward hyperinflammatory phenotypes. A recurring mechanistic theme is NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation and interleukin-1 family signaling, which may create a feed-forward loop in which mutant clones amplify inflammatory circuits that, in turn, may enhance clonal fitness and contribute to thrombogenicity across multiple cellular compartments. We propose the 'thrombotic niche' as a conceptual, multi-compartment model encompassing mutant hematopoietic stem cells, hyperinflammatory myeloid effectors, hyperreactive platelets, platelet-leukocyte aggregates, and activated endothelium, but it remains a hypothesis-generating framework that lacks direct prospective clinical validation. Current cytoreductive strategies inadequately address this underlying biology, leaving substantial residual vascular risk. Emerging anti-inflammatory and anti-clonal strategies targeting interleukin-1 beta (IL-1β) (canakinumab), mutant-selective JAK2 inhibition, NLRP3 inflammasome blockade, and P-selectin-mediated adhesion are biologically plausible, but their ability to reduce thrombotic events in MPN remains unproven and should be viewed as hypothesis-generating rather than established clinical benefit. We conclude by outlining a translational research agenda integrating inflammation-aware risk stratification, niche-directed imaging, and spatial multi-omics to guide precision anti-inflammatory interventions in MPN.
2025-12-09 | Integrin-dependence of extramedullary erythropoiesis in the spleen of Jak2-V617F positive myeloproliferative neoplasm in mice.
The molecular mechanisms driving splenomegaly in myeloproliferative neoplasms (MPNs) remain poorly understood. Utilizing the Jak2-V617F knock-in mouse model, we investigated the role of β1- and β2-integrins in regulating spleen volume and spleen weight. The response to neutralizing antibodies against VLA-4 and the β2-integrin chain, as well as to isotype controls, was evaluated by serial intraindividual magnetic resonance imaging, by assessment of spleen weight and by analysis of the cellular composition of spleens. Short-term anti-VLA-4/β2-integrin treatment (applied on day 1 and evaluated at day 8) significantly reduced the spleen volume by 30% compared with the immunoglobulin G (IgG) control. At the cellular level, anti-integrin treatment led to a substantial 30% decrease in erythroblast counts and a 23% reduction in basophilic erythroblasts within the spleen, as compared with the isotype control. Furthermore, immunohistochemistry analysis of spleen sections revealed that CD71 (= Transferrin receptor protein 1) expression in spleen remained largely unchanged, whereas there was a clear reduction in Ter119 expression upon anti-integrin treatment. These data suggest that the substantial decrease in erythroblasts following anti-integrin treatment is a primary factor contributing to the overall reduction in spleen size. To study the spleen architecture, multiepitope ligand cartography (MELC) analysis of spleen sections was applied. This demonstrated that the spatial distribution of the marginal zone, red pulp, and white pulp remained unaltered upon anti-integrin treatment in JAK2-V617F knock-in mice. In summary, the present study identified a previously unrecognized role of the β1-integrin VLA-4 and of β2-integrin chains in extramedullary erythropoiesis of the spleen in JAK2-V617F-induced disease.
2025-11-19 | Impaired IL-10 Receptor Signaling Leads to Inflammation Induced Exhaustion in Hematopoietic Stem Cells.
Hematopoietic stem cells require tight regulation to rapidly initiate emergency hematopoiesis in response to pathogens, but chronic activation leads to proliferation induced exhaustion. Timely reentry into quiescence after inflammatory stimuli is essential for long term sustained HSC maintenance. We identify IL-10R signaling, an established negative feedback regulator in mature myeloid cells, as critical for returning HSCs to quiescence. IL-10R blockade prolongs HSC cycling and sustains activated transcriptional programs after acute inflammation. With chronic exposure, blockade increases cumulative divisions and accelerates aging hallmarks, including myeloid bias, loss of polarity, and functional defects, under conditions that do not otherwise exhaust HSCs when IL-10R signaling is intact. Jak2 V617F mutant HSCs resist the aging acceleration induced by blockade. Consistent with this resistance, IL-10R blocking antibody promotes Jak2 V617F clonal expansion and augments the myeloproliferative neoplasm phenotype. Together, these findings identify IL-10R signaling as a key coordinator of post inflammatory return to quiescence and suggest that modulating this axis could preserve HSCs and shape clonal hematopoiesis. Wadley et al. show that IL-10 receptor signaling restrains inflammation-induced hematopoietic stem cell cycling and exhaustion; its blockade prolongs cycling, accelerates aging-related decline, and selectively favors Jak2 V617F mutant HSCs, establishing IL-10 signaling as a critical regulator of inflammatory HSC exhaustion and malignant clonal evolution.
2025-07-02 | Cellular expression of PD-1, PD-L1 and CTLA-4 in patients with JAK2V617F mutated myeloproliferative disorders.
The acquired, somatic JAK2V617F mutation is the most common molecular aberration in patients with myeloproliferative neoplasms (MPN) and also significantly involved in the regulation of T cell immunity. PD-1, PD-L1 and CTLA-4 are key immune checkpoint regulators that are elevated in patients with solid tumors, infectious diseases and chronic inflammation. We aimed further investigating the significance of immune checkpoint expression in JAK2V617F positive MPN. The surface expression of PD-L1, PD-1 and CTLA-4 on peripheral blood leukocytes was determined by flow cytometry in 27 patients with JAK2V617F positive MPN and in a control group of 26 healthy individuals and analyzed by immune checkpoint and leukocyte subpopulation. In addition, the concentration of soluble PD-L1 (sPD-L1) in plasma was examined by ELISA. PD-1, PD-L1 and CTLA-4 are significantly overexpressed on the surface of granulocytes in JAK2 positive patients compared to the control group. Soluble PD-L1 (sPD-L1) is elevated in the plasma of JAK2 positive patients and increases with decreased renal function. In CD8+ T-cells and CD4+ T-cells there is a significant negative correlation between PD-1 expression or sPD-L1 concentration and their corresponding cell count. Our study shows a significant increase of immune checkpoint regulators on the cellular surface as well as soluble PD-L1 in JAK2 mutated patients compared to healthy individuals. Increased activation of the JAK2/STAT signaling pathway by JAK2V617F appears to be a mechanism of reduced immune activation in patients with MPN. Immune checkpoint inhibition might therefore represent a potential additional therapeutic target in this disease group.
2025-06-12 | IL-18 inhibition enlarges lesions, necrotic cores and thickens fibrous caps in Jak2 V617F clonal hematopoiesis-driven atherosclerosis.
Inflammasome activation promotes atherosclerosis in clonal hematopoiesis (CH). Active inflammasomes secrete both IL-1β and IL-18. Plasma IL-18 levels are elevated in Jak2 VF CH. Genetic deficiency of IL-18 has been shown to reduce atherosclerosis in non-CH murine models. However, whether IL-18 inhibition promotes atherosclerosis in control or Jak2 VF CH is unknown. Ldlr -/- mice were transplanted with bone marrow (BM) from Mx1-cre Jak2 VF (20%) and wild-type (80%) mice or with control BM, fed a Western-type diet (WTD) for 8, 10 or 16 weeks and administered control or IL-18 IgG from 4 weeks onwards. IL-18 antibody treatment increased plaque collagen content and cap thickness. Unexpectedly, IL-18 antibody treatment increased the size of early lesions and promoted formation of advanced lesions with large necrotic cores in Jak2 VF CH mice. IL-18 antibody treatment was associated with diminished interferon (IFN)-γ and AIM2 levels and reduced macrophage pyroptosis especially in Jak2 VF CH mice. However, IL-18 antibodies increased cleaved Caspase-3 and TUNEL + macrophages (indicating increased apoptosis) and reduced efferocytosis. Sc-RNA-seq analysis showed that IL-18 antibody treatment reduced expression of MHC class II genes, a marker of IFN-γ signaling, and of genes mediating efferocytosis ( Mertk and Axl) , in resident-like macrophage subpopulations in Jak2 VF CH mice. Consistently, IFN-γ injection increased Axl and Mertk expression in resident peritoneal macrophages. Despite improvements in collagen and fibrous cap thickness in Jak2 VF CH mice, IL-18 antibody treatment increased advanced necrotic lesions, reflecting a shift from pyroptotic to apoptotic cell death coupled with defective efferocytosis, events which were coordinated by reduced IFN-γ signaling. These findings indicate a mixed atherosclerosis phenotype resulting from IL-18 inhibition, advocating for alternative therapeutic strategies. Inhibition of IL-18 has been considered as a novel therapeutic approach to reduce atherosclerosis and stabilize atherosclerotic plaques. We show that IL-18 antibodies have adverse effects on atherosclerotic lesional necrosis, calling this approach into question. Inflammasome activation produces active IL-1 and IL-18 and worsens atherosclerosis in clonal hematopoiesis (CH) however the contribution of IL-18 is unknown. Antibody inhibition of IL-18 increased plaque collagen but also increased early lesion area and late lesions with large necrotic cores in Jak2 VF CH mice. There was a reversal of AIM2 inflammasome activation but a switch to apoptosis which along with reduced efferocytosis increased necrosisThese events appeared to be coordinated by reduced IFN-γ which increased collagen but also decreased expression of efferocytotic genes. Our studies call into question whether inhibition of IL-18 would stabilize plaques in CH.
cell therapies
2026-03-12 | Clinical Outcomes of Allogeneic Stem Cell Transplantation in Myelofibrosis - A Single Center Experience.
There is paucity of data on the outcomes of allogeneic stem cell transplantation (allo-SCT) for myelofibrosis, from developing countries. This is a retrospective analysis of patients undergoing allogeneic stem cell transplant for myelofibrosis at our center between January 1998 to December 2023. Thirty-four patients underwent allogeneic transplantation with a median age of 46 (19-68) years with 24 (70.6%) being males. The median dynamic international prognostic scoring system (DIPSS) Score was 3 (2-4). JAK2 was the most common driver mutation, in 10 (34.5%) patients. Majority of patients received reduced intensity conditioning with Fludarabine-Melphalan +/-total body irradiation (n=32) and all had peripheral blood grafts with donor source being matched sibling in 22 (64.7%), unrelated donor in 9 (26.5%) [7 full HLA match, one 9/10 HLA match and one 8/10 HLA match] and haploidentical in 3 (8.8%). The median CD34 cell dose infused was 9.9 (3.4-22) × 106/kg. The majority received calcineurin inhibitor + methotrexate (n=28) as Graft versus Host Disease (GVHD) prophylaxis. Two patients died before day 14 due to sepsis while 3 (9.3%) had primary graft failure. Neutrophil engraftment occurred in 29 patients (85.3%) at a median of 15 (range 8-25) days. Acute GVHD was noted in 20 (58.8%) patients with grade 3-4 GVHD in 13 (38.2%). Chronic GVHD was noted in 12 patients with 4 being extensive chronic GVHD as per revised Seattle criteria. On last follow up, 15 (44.1%) patients are alive while 19 have died. Allo-SCT for myelofibrosis is associated with reasonable cure rates, however strategies to reduce graft failure and GVHD are required.
2024-06-17 | A comparison between erythrocytapheresis and venesection for the treatment of JAK2-mutated polycythaemia.
JAK2-mutated polycythaemia vera (PV) is associated with reduced survival because of thrombotic events and haematological disease transformation. Therapeutic venesection has traditionally been used to lower haematocrit, but the technique of erythrocytapheresis has emerged over the last decade. To compare erythrocytapheresis with venesection as treatment for PV by assessing medical efficacy and financial viability. One hundred sixteen patients with PV who received red cell depletion therapy at Barwon Health between 2014 and 2021 were identified. The haematocrit drop after each session, interval between treatment times and number of sessions required to achieve a haematocrit <0.45 were compared with an independent t test. Thrombosis rates were compared with Pearson's chi-squared test. Cost-funding analysis was done by assessing the Weighted Inlier Equivalent Separation and National Weighted Activity Unit funding models. Patients treated with erythrocytapheresis achieved a greater haematocrit drop each treatment session (0.075 vs 0.03, P < 0.01), required fewer sessions to achieve a haematocrit <0.45 (1 vs 4, P < 0.01) and experienced fewer thrombotic complications (8.7% vs 32.1%, P = 0.02) than those treated with venesection. Cost-funding analysis demonstrated that erythrocytapheresis was more financially viable with a surplus of AU$297 per session compared to a deficit of AU$176 with venesection. Even if funding for venesection is increased, the cost of erythrocytapheresis may be mitigated by a lower number of procedures required per year (3.8 vs 5.3, P < 0.01). Erythrocytapheresis is more efficacious than venesection for the treatment of PV and is accompanied by rapid reductions in haematocrit and reduced thrombotic complications.
2023-12-16 | JAK2 R683S Mutation Resulting in Dual Diagnoses of Chronic Eosinophilic Leukemia and Myelodysplastic/Myeloproliferative Overlap Syndrome.
A 66-year-old male presented with hypereosinophilia, thrombocytosis, extensive thrombosis refractory to direct oral anticoagulant therapy, and evidence of end-organ damage, including rash, splenic infarcts, and pulmonary infiltrates. Bone marrow biopsy revealed myeloid malignancy consistent with both chronic eosinophilic leukemia and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) with SF3B1 mutation and thrombocytosis. Next-generation sequencing of the patient's eosinophils and neutrophil compartments revealed pathologic variants in EZH2 and SF3B1 in addition to a noncanonical JAK2 R683S mutation that has not been previously described in myeloproliferative disorders or other chronic myeloid neoplasms. These mutations were not present in the patient's lymphoid cell fraction, suggesting that the hematopoietic malignancy arose in a myeloid-committed progenitor cell. Based on this case and previous work from our group, we propose that noncanonical JAK2 mutations may permit signal transduction that biases toward eosinophilic differentiation in chronic myeloid neoplasms. Although the patient's blood counts initially responded to ruxolitinib and hydroxyurea, the response was not durable. Early referral for allogenic bone marrow transplant appears necessary to prevent long-term complications and disease progression in myeloid neoplasms with clonal hypereosinophilia driven by noncanonical JAK2 mutations.
2019-04-17 | Functional interdependence of hematopoietic stem cells and their niche in oncogene promotion of myeloproliferative neoplasms: the 159th biomedical version of "it takes two to tango".
The role of stem cells in normal and neoplastic hematopoiesis is well established. However, neither normal nor neoplastic hematopoietic stem cells (HSCs) develop in isolation and accumulating evidence indicates that a critical developmental role is played by the perivascular "niche." The cellular, humoral, and cell surface contacts that provide the proper environment for HSC survival, proliferation, and differentiation are becoming increasingly better understood. A number of studies have established that endothelial cells (ECs), several types of perivascular stromal cells, and megakaryocytes (MKs) provide several cell surface and secreted molecules required for HSC development. Accumulating evidence also indicates that the normal stem cell niche is altered in patients with hematological neoplasms and that the "neoplastic niche" plays an important role in promoting malignant and suppressing normal blood cell development in such patients. To explore this concept in the myeloproliferative neoplasms (MPNs), we employed a murine model to determine the effects of Jak2V617F, an oncogene found in a majority of such patients, in marrow ECs and MKs and their effect on promoting neoplastic and suppressing normal hematopoiesis. We found that Jak2V617F has profound effects on both cell types, which together are critical for the growth advantage and radioresistance shown by Jak2V617F-bearing HSCs. Such findings should provide new approaches to the treatment of patients with MPNs.
2018-12-11 | MLL-PTD in a 13-year-old patient with blast phase myeloproliferative neoplasm: A case report.
The risk of leukemic transformation in myeloproliferative neoplasm (MPN) has been increasing with time. Partial Tandem Duplications of the MLL gene (MLL-PTD) has been reported in de novo acute myeloid leukemia (AML), but not in MPN blast phase. The post-MPN AML developed adverse clinical outcomes, which showed no noticeable improvement over the past 15 years. Therefore, the mechanisms and therapeutic approaches of post-MPN AML need to be deeply studied. In this study, we present a JAK2V617F positive MPN patient who experienced fatigue and splenomegaly, transforming into JAK2V617F negative AML. A diagnosis of acute monocytic leukemia was made in MPN blast phase. The patient received chemotherapy and allogeneic hematopoietic stem cell transplantation (Allo-SCT). The patient achieved complete remission twice, but relapsed twice. Relapse-free survival was only 3 months. She died about 24 months after her diagnosis. MLL-PTD occurs in the progression of JAK2V617F positive MPN into JAK2V617F negative AML, which may be a novel mechanism of MPN blast phase and helpful for post-MPN AML diagnosis. Allo-SCT may be a good choice for post-MPN AML with MLL-PTD. More therapeutic strategies need to be explored for a better prognosis in these patients.
other
2025-05-28 | CRISPR/Cas9-Based Modeling of JAK2 V617F Mutation in K562 Cells Reveals Enhanced Proliferation and Sensitivity to Therapeutic Agents.
The Janus kinase 2 (JAK2) protein fulfills an important role in hematopoiesis via the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway, as it provides the genetic driver of BCR::ABL1-negative myeloproliferative neoplasms (MPNs), which are clinically manifested as polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The most common cause of MPNs is the mutation of JAK2 V617F in the JAK2 gene, which results in increased cell proliferation. However, both the pathogenesis and treatment regimen of BCR::ABL1-negative MPNs remain poorly understood. The aim of the present study was to establish K562 cell lines with a point mutation in exon 14 (JAK2p.V617F) using CRISPR/Cas9 technology. The modified JAK2 V617F cell lines were examined for the gene mutation using droplet digital PCR (DDPCR), and the presence of the mutation was confirmed by DNA sequencing. Modified cells were characterized by measuring JAK2 gene expression and the extent of cell proliferation. Interferon α2a (IFN-α2a) and arsenic trioxide were also administered to the cells to explore their potential effects. The JAK2 V617F-mutated cells were found to exhibit a higher level of JAK2 gene expression compared with the wild type. Interestingly, a significant increase in the proliferation rate was observed with the modified cells compared with the wild type cells (p < 0.001), as assessed from the JAK2 gene expression levels. Furthermore, the treatments with IFN-α2a and arsenic trioxide led to the preferential suppression of the cell proliferation rate of the K562 expressing mutant JAK2 cells compared with the wild type cells, and this suppression occurred in a dose-dependent manner(p < 0.01). Moreover, the modified cells were able to differentiate into megakaryocyte-like cells following stimulation with phorbol 12 myristate 13 acetate (PMA). Taken together, the results of the present study have shown that the CRISPR/Cas9-modified JAK2 V617F model may be used as a disease model in the search of novel therapies for MPNs.
2025-02-28 | Suppressed activation of the IRF7 and TLR9 by JAK2V617F gold nanoparticles.
Philadelphia chromosome-negative myeloproliferative neoplasms (Ph-MPNs) are characterized by the overproduction of myeloid cells and a lack of response to cytokine signaling, along with genomic instability and the accumulation of nucleic acids in the cytoplasm. In this study, we investigated the effects of oligonucleotide-gold nanoparticle conjugates (ON-GNPs) targeting JAK2 or JAK2V617F mRNAs on nucleic acid-sensing pathways in HEL, SET2, and K562 cell lines. We evaluated changes in gene expression related to TLR9 and cGAS/STING pathways, RAGE/TLR9 receptor dynamics, and inflammatory cytokine release over short-term (0.5-2 h) and long-term (24-72 h) exposures. Our results demonstrated that ON-GNPs transiently suppressed TLR9, IRF7, and NFKB1 expression during the short term, followed by significant upregulation after 24 h, persisting up to 72 h. Notably, JAK2V617F-targeting ON-GNPs induced heightened IRF7 activation in HEL and SET2 cells after 24 h without affecting TLR9/RAGE expression. Additionally, IL-8 secretion increased in HEL and SET2 culture media after 72 h, correlating with interferon pathway activation. This study reveals that complementary ON-GNPs can modulate nucleic acid-sensing pathways, suppressing IL-8 and inflammatory signaling in the short term while inducing delayed activation of TLR9 and IRF7 in the presence of JAK2V617F. These findings provide a promising foundation for developing ON-GNP-based therapeutic strategies to manage inflammation and disease progression in Ph-MPNs.
2024-10-01 | Differential modulation of mutant CALR and JAK2 V617F-driven oncogenesis by HLA genotype in myeloproliferative neoplasms.
It has been demonstrated previously that human leukocyte antigen class I (HLA-I) and class II (HLA-II) alleles may modulate JAK2 V617F and CALR mutation (CALRmut)-associated oncogenesis in myeloproliferative neoplasms (MPNs). However, the role of immunogenetic factors in MPNs remains underexplored. We aimed to investigate the potential involvement of HLA genes in CALRmut+ MPNs. High-resolution genotyping of HLA-I and -II loci was conducted in 42 CALRmut+ and 158 JAK2 V617F+ MPN patients and 1,083 healthy controls. A global analysis of the diversity of HLA-I genotypes revealed no significant differences between CALRmut+ patients and controls. However, one HLA-I allele (C*06:02) showed an inverse correlation with presence of CALR mutation. A meta-analysis across independent cohorts and healthy individuals from the 1000 Genomes Project confirmed an inverse correlation between the presentation capabilities of the HLA-I loci for JAK2 V617F and CALRmut-derived peptides in both patients and healthy individuals. scRNA-Seq analysis revealed low expression of TAP1 and CIITA genes in CALRmut+ hematopoietic stem and progenitor cells. In conclusion, the HLA-I genotype differentially restricts JAK2 V617F and CALRmut-driven oncogenesis potentially explaining the mutual exclusivity of the two mutations and differences in their presentation latency. These findings have practical implications for the development of neoantigen-based vaccines in MPNs.
2023-03-14 | An arginase1- and PD-L1-derived peptide-based vaccine for myeloproliferative neoplasms: A first-in-man clinical trial.
Arginase-1 (ARG1) and Programed death ligand-1 (PD-L1) play a vital role in immunosuppression in myeloproliferative neoplasms (MPNs) and directly inhibit T-cell activation and proliferation. We previously identified spontaneous T-cell responses towards PD-L1 and ARG1 derived peptide epitopes in patients with MPNs. In the present First-in-Man study we tested dual vaccinations of ARG1- derived and PD-L1-derived peptides, combined with Montanide ISA-51 as adjuvant, in patients with Janus Kinase 2 (JAK2) V617F-mutated MPN. Safety and efficacy of vaccination with ARG1- derived and PD-L1-derived peptides with montanide as an adjuvant was tested in 9 patients with MPN The primary end point was safety and toxicity evaluation. The secondary end point was assessment of the immune response to the vaccination epitope (www.clinicaltrials.gov identifier NCT04051307). The study included 9 patients with JAK2-mutant MPN of which 8 received all 24 planned vaccines within a 9-month treatment period. Patients reported only grade 1 and 2 vaccine related adverse events. No alterations in peripheral blood counts were identified, and serial measurements of the JAK2V617F allelic burden showed that none of the patients achieved a molecular response during the treatment period. The vaccines induced strong immune responses against both ARG1 and PD-L1- derived epitopes in the peripheral blood of all patients, and vaccine-specific skin-infiltrating lymphocytes from 5/6 patients could be expanded in vitro after a delayed-type hypersensitivity test. In two patients we also detected both ARG1- and PD-L1-specific T cells in bone marrow samples at the end of trial. Intracellular cytokine staining revealed IFNγ and TNFγ producing CD4+- and CD8+- T cells specific against both vaccine epitopes. Throughout the study, the peripheral CD8/CD4 ratio increased significantly, and the CD8+ TEMRA subpopulation was enlarged. We also identified a significant decrease in PD-L1 mRNA expression in CD14+ myeloid cells in the peripheral blood in all treated patients and a decrease in ARG1 mRNA expression in bone marrow of 6 out of 7 evaluated patients. Overall, the ARG1- and PD-L1-derived vaccines were safe and tolerable and induced strong T-cell responses in all patients. These results warrant further studies of the vaccine in other settings or in combination with additional immune-activating treatments.
2022-01-05 | Tmprss6-ASO as a tool for the treatment of Polycythemia Vera mice.
Polycythemia Vera (PV) is a chronic myeloproliferative neoplasm resulting from an acquired driver mutation in the JAK2 gene of hematopoietic stem and progenitor cells resulting in the overproduction of mature erythrocytes and abnormally high hematocrit, in turn leading to thromboembolic complications. Therapeutic phlebotomy is the most common treatment to reduce the hematocrit levels and consequently decrease thromboembolic risk. Here we demonstrate that, by using the iron restrictive properties of the antisense oligonucleotides against Tmprss6 mRNA, we can increase hepcidin to achieve effects equivalent to therapeutic phlebotomy. We provide evidence that this less invasive approach could represent an additional therapeutic tool for the treatment of PV patients.
small molecules
2026-08-14 | Identification of Novel Small-Molecule Janus Kinase 1 and 2 Inhibitors Through Structure-Based Virtual Screening, In Vitro Assays, and Molecular Dynamics Simulations.
Janus kinases (JAKs) are central mediators of cytokine-driven signal transducer and activator of transcription (STAT) signaling, and dysregulation of the JAK-STAT axis is implicated in inflammatory, autoimmune, and neoplastic diseases. To identify new small-molecule inhibitors of Janus kinase 1 (JAK1) and Janus kinase 2 (JAK2), we implemented an integrated virtual screening workflow combining structure-based docking and ligand-based prioritization using the InterBioScreen (IBS) compound library. A drug-likeness filter reduced 521,627 IBS molecules to 116,064 candidates, which were then docked into the ATP-binding sites of JAK1 (PDB ID: 4EI4) and JAK2 (PDB ID: 6VGL) using Glide SP; compounds were prioritized using docking score thresholds of <- 8.5 kcal/mol (JAK1) and <- 9.0 kcal/mol (JAK2), yielding 407 JAK1- and 298 JAK2-focused hits. Subsequent analysis shortlisted 42 candidates for enzymatic evaluation. In vitro kinase assays identified multiple nanomolar inhibitors, including compound 1-3 (IC50 = 0.032 μM) among the most potent for JAK1 and compound 2-8 (IC50 = 0.026 μM) for JAK2. Finally, 100 ns molecular dynamics (MD) simulations supported stable binding for representative complexes, with persistent hinge-region interactions for compound 1-3 in JAK1 (e.g., Glu957/Leu959) and compound 2-8 in JAK2 (e.g., Glu930/Leu932), consistent with a stable interaction network in the active site. Collectively, these results define validated IBS-derived hit scaffolds for further optimization and selectivity profiling toward JAK-targeted therapeutics.
2026-07-14 | Uncompetitive Allosteric Inhibition of PTP1B by BP-1-102 Reveals a Potential Dual-Target Strategy toward the PTP1B-STAT3 Oncogenic Axis: Biochemical and Computational Evidence.
Selective PTP1B inhibitors paradoxically potentiate oncogenic STAT3 signaling by restoring JAK2 activity, underscoring the need for dual-target strategies. Here we report that BP-1-102, an orally bioavailable STAT3 SH2 domain inhibitor, also potently inhibits PTP1B with IC50 values of 5.32 μM (hPTP1B1-400) and 11.7 μM (hPTP1B1-285), with ≥37.7-fold selectivity over TCPTP. Kinetic analysis identified an uncompetitive mechanism, suggesting inhibitor binding to the enzyme-substrate complex at a site distal to the active site. Docking and 500 ns molecular dynamics simulations revealed a dual-anchor binding mode involving the 113-123 loop (Cys121) and the proline-rich C-terminal disordered region, a structural interface absent in TCPTP. Umbrella sampling confirmed favorable passive membrane permeability through a tumor-mimetic bilayer (ΔG = -13.83 kcal/mol). These results propose BP-1-102 as a candidate for dual-function inhibitor of the PTP1B-JAK2-STAT3 oncogenic axis, providing a physicochemical and mechanistic rationale for its further evaluation in tumors where both targets are coactivated.
2026-07-14 | Design, synthesis, and activity study of heterocyclic derivatives as JAK inhibitors.
The Janus kinase (JAK) family plays a central role in regulating inflammation and fibrosis through the JAK/STAT signaling pathway, making it an attractive therapeutic target for immune-mediated diseases. In the present study, structural modifications of the quinazoline core were systematically explored to identify potent JAK inhibitors. A CXCL10-based screening strategy identified compound 22a as a promising lead, exhibiting strong inhibitory activity in HaCaT cells with an IC50 value of 308 nM. Subsequent kinase assays demonstrated that compound 22a exhibits higher inhibitory potency toward JAK1 (IC50 = 37.86 nM) compared to JAK2 (IC50 = 102.5 nM), JAK3 (IC50 = 69.35 nM), and TYK2 (IC50 = 2142 nM). Mechanistic studies revealed a dose-dependent suppression of STAT1 phosphorylation, confirming inhibition of the JAK1/2-STAT1 signaling pathway. In addition, molecular docking and molecular dynamics simulations were performed to elucidate and validate the binding mode of compound 22a within the JAK1 active site. Collectively, these results indicate that the developed quinazoline derivatives represent promising leads for the further development of selective JAK1 inhibitors.
2026-07-07 | Janus kinase 2 activation loop as a regulator of catalysis and trans-activation.
Protein kinases regulate essential cellular processes such as apoptosis, proliferation, and growth. Precise regulation of kinase activity is critical for proper signal transduction and is often mediated by activation-loop phosphorylation. Janus kinases (JAKs) employ a unique regulatory mechanism: they remain autoinhibited by their pseudokinase domains until cytokine stimulation triggers dimerization and trans-phosphorylation of two activation-loop tyrosines. Despite its relevance for JAK inhibitor design, the molecular mechanism of JAK activation by activation-loop phosphorylation is not fully understood. Here, we show that phosphorylation of the JAK2 activation loop is essential for stabilizing substrate binding and in the absence of phosphorylation, the activation loop fails to bind substrates. Our findings reveal a unique regulatory role for the activation loop in JAK2, where phosphorylation enhances loop stability rather than inducing a major conformational change as in most protein kinases. In addition, the flexibility of the unphosphorylated activation loop allows conformational changes required for trans-phosphorylation during JAK activation. These insights provide a mechanistic basis for JAK activation and offer new insights for the development of JAK inhibitors.
2026-07-03 | ARHGEF2::JAK2 Fusion Drives Leukemogenesis via CCNB1-Dependent Signaling.
Leukemia is a heterogeneous malignancy with poor outcomes in refractory cases, and fusion genes involving JAK2 are known oncogenic drivers. The ARHGEF2::JAK2 fusion gene combines hyperactive kinase signaling with cytoskeletal regulation, but its functional role in leukemia remains unclear. This study aimed to characterize the oncogenic mechanisms of ARHGEF2::JAK2 and identify key downstream targets. Ba/F3 cells transduced with ARHGEF2::JAK2 and mouse xenograft models were used to assess proliferation, apoptosis, and leukemogenic potential. RNA sequencing, qPCR, and Western blotting were used to analyze downstream targets, followed by functional validation via shRNA knockdown. Results showed that ARHGEF2::JAK2 conferred cytokine-independent growth, suppressed apoptosis, and drove aggressive leukemia in mice. Ruxolitinib ameliorates ARHGEF2::JAK2-induced leukemogenesis in vivo. Transcriptomic analysis identified CCNB1 as a critical downstream effector, and its knockdown reversed the oncogenic effects of ARHGEF2::JAK2, improving survival and reducing organ infiltration. These findings demonstrate that ARHGEF2::JAK2 promotes leukemogenesis via CCNB1 upregulation, suggesting CCNB1 as a potential therapeutic target. This study provides new insights into fusion-driven leukemia pathogenesis.
proteins
2026-08-08 | Hierarchical mathematical modelling of patients with myeloproliferative neoplasms captures interferon-α treatment responses and allows for personalised and population predictions.
The Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) are a group of haematological malignancies triggered by a driver mutation, most commonly the JAK2 V617F mutation, which is acquired in a haematopoietic stem cell. The diseases are characterised by an overproduction of myeloid cells and may result in severe complications such as thrombosis, myelofibrotic transition, and potentially progression to acute myeloid leukaemia. Treatment with interferon-α (IFN-α) can potentially deplete the disease-driving malignant stem cell population, thereby leading to long-term remission. We extend a mechanistic compartmental differential equation model of MPN progression to account for the effects of IFN-α treatment. In agreement with experimental mouse studies, we assume that IFN-α acts through effects on malignant stem cell differentiation and malignant progenitor and precursor cell apoptosis. We use a hierarchical Bayesian inference procedure to infer the drug response parameters of the model based on measurements of the JAK2 V617F variant allele frequency (VAF) for N=56 patients from the Danish DALIAH study, both on the individual and the population level, with 14 patients left out for subsequent testing. The model estimates are found to agree with data. The drug response parameters are found to act synergistically on the reduction of JAK2 VAF, with the model being able to capture qualitatively different types of treatment responses. Using the inferred information about the population distribution of drug response parameters is found to improve predictions compared to predictions without prior knowledge on a testing cohort. Such predictions may aid clinical decision-making regarding IFN-α treatment in patients with MPNs.
2026-06-26 | A Hidden Driver Mutation in Myeloproliferative Neoplasms: SH2B3 and Diagnostic Implications and Response to Ropeginterferon Alfa-2b.
Myeloproliferative neoplasms (MPNs) are commonly linked to driver mutations in the JAK2, MPL, and CALR genes. In contrast, SH2B3 (LNK) mutations are uncommon and remain an under-characterized contributor to dysregulated JAK-STAT signaling. The clinical features and treatment responsiveness of SH2B3-mutated MPNs are not well defined, and data on outcomes with ropeginterferon alfa-2b in this molecular subgroup are limited. We report a 75-year-old man who presented for evaluation of headache, generalized bone pain, and night sweats and was found to have abnormal blood counts including persistent leukocytosis, erythrocytosis, and thrombocytosis. Prior molecular testing was negative for JAK2, MPL, and CALR mutations. Bone marrow examination showed hypercellularity with panmyelosis, mild megakaryocytic atypia, and WHO grade 1 reticulin fibrosis. Hematologic next-generation sequencing identified a pathogenic SH2B3 c.1481C>G (p.Ser494*) nonsense mutation, predicted to result in a loss of SH2B3's C-terminal regulatory domain. Given the tri-lineage cytoses and marrow findings, a diagnosis of SH2B3-mutated MPN was established. He was started on ropeginterferon alfa-2b, resulting in resolution of his symptoms and complete hematologic response (WBC ≤ 10 × 103/μL, Hct ≤ 45%, and PLT ≤ 400 × 103/μL) within 12 weeks, without the need for phlebotomy or treatment-limiting adverse effects. This case underscores the clinical significance of SH2B3 mutations as a driver of triple-negative MPNs and supports their inclusion in molecular evaluation when classical mutations are absent. The favorable clinical and hematologic response to ropeginterferon alfa-2b suggests that interferon-based therapy may be effective in SH2B3-mutated MPNs.
2026-06-11 | Synergistic cooperation between progranulin and Jak2/Stat3 signaling determines definitive myeloid cell fate.
Perturbations in cell fate disrupt tissue homeostasis and drive diseases such as cancer. The JAK/STAT pathway is central to hematopoietic malignancies, yet its regulators in cell fate decisions remain poorly defined. Here, we identify progranulin (GRN) as a critical determinant of myeloid fate through the regulation of JAK2/STAT3 signaling. Using inducible stat3 and grna zebrafish models, knockout approaches, FACS, transcriptomics, and CUT&RUN, we show that Stat3 induces grna, which in turn amplifies stat3 expression, reinforcing myeloid over erythroid commitment. Lineage tracing and live imaging reveal that this Grna/Stat3 feedback operates during definitive, but not primitive, myelopoiesis. Functionally, definitive myeloid cells drive tissue repair, whereas primitive counterparts are less effective. Myeloid differentiation in a human leukemia line required GRN co-stimulation of JAK2/STAT3, highlighting its conserved role in fate determination. These findings uncover a regulatory axis controlling hematopoietic commitment and identify GRN as a potential therapeutic target in diseases with aberrant JAK2/STAT3 activation.
2026-01-16 | IFNα2b modulates anti-tumor immune responses involving STAT3-associated dendritic cell dysfunction in JAK2v617f-positive myeloproliferative neoplasms.
To define JAK2v617f-induced immune alterations, focusing on STAT3-mediated dendritic cell dysfunction, and evaluate whether IFNα2b restores anti-tumor immunity in JAK2v617f-positive myeloproliferative neoplasms. Integrated flow cytometry and single-cell RNA sequencing profiled immune landscapes and signaling pathways, while functional assays assessed dendritic cell differentiation, T cell activation, and IFNα2b-mediated immune restoration. JAK2v617f was associated with increased STAT3 activation in myeloid cells, accompanied by elevated expression of immunosuppressive mediators such as FGL2, impaired monocyte-to-DC differentiation, reduced cDC1/cDC2 subsets, and diminished T cell activation, consistent with an immunosuppressive immune landscape. IFNα2b treatment was associated with attenuation of STAT3/FGL2 signaling and partial restoration of DC-mediated T cell priming, with more pronounced immunomodulatory effects observed in JAK2v617f-positive myeloproliferative neoplasms compared with other subtypes. Our findings indicate that JAK2v617f is associated with STAT3-dependent dendritic cell dysfunction that contributes to an immunosuppressive milieu. IFNα2b modulates this pathway and partially restores DC-T cell interactions, highlighting its potential as an immunomodulatory strategy in JAK2v617f-positive myeloproliferative neoplasms.
2026-01-10 | Real-World Retrospective Report on the Efficacy, Tolerability, and Molecular Responses to Ropeginterferon-α2b in Patients with Myeloproliferative Neoplasms.
Background: Ropeginterferon alfa-2b (Ropeg-IFNa) is increasingly used in myeloproliferative neoplasms (MPN), particularly polycythemia vera, but real-world data across subtypes are limited. We evaluated clinical and molecular responses to Ropeg-IFNa in routine practice. Methods: We retrospectively analyzed 20 JAK2V617F-positive MPN patients treated at a tertiary center. Baseline features, dosing, treatment line, hematologic responses, adverse events, and serial JAK2V617F variant allele frequency (VAF) were extracted from records. Results: Median age at initiation was 53 years; 55% were ELN high-risk. Ropeg-IFNa was started first-line or after peginterferon alfa-2a, hydroxyurea, or a tapered JAK2 inhibitor. Mean treatment duration was 14 ± 11 months at 195 ± 143 µg Q2W. Hematologic control increased from 45% at the start to 60% at the last follow-up. Among patients with serial molecular monitoring (n = 11), median JAK2V617F VAF declined from 21.2 to 12.7%. Ropeg-IFNa was generally well tolerated; adverse effects were mostly manageable, although 3/20 (15%) discontinued due to side effects, including mood disturbances, while others continued with supportive care and dose adjustments. Conclusions: In this single-center cohort, Ropeg-IFNa was tolerable and associated with improved hematologic control and modest VAF reductions, supporting its use in multi-subtype MPN cohorts. These findings underscore the value of longitudinal driver-mutation monitoring during therapy.
antibodies
2026-06-28 | Beyond the JAK2 mutation: The inflammasome, clonal stability, and the thrombotic niche in myeloproliferative neoplasms.
Philadelphia-negative myeloproliferative neoplasms (MPNs) carry a disproportionate thrombotic burden that cannot be explained by conventional cardiovascular risk factors or blood count parameters alone. This review synthesizes emerging evidence positioning MPN-associated thrombosis as a distinct pathobiologic entity, clonal thrombo-inflammation, driven by the convergence of somatic mutations and innate immune activation. We examine the continuum from clonal hematopoiesis of indeterminate potential (CHIP) to overt MPN, highlighting how Janus kinase 2 (JAK2)V617F and other driver mutations reprogram myeloid cells toward hyperinflammatory phenotypes. A recurring mechanistic theme is NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation and interleukin-1 family signaling, which may create a feed-forward loop in which mutant clones amplify inflammatory circuits that, in turn, may enhance clonal fitness and contribute to thrombogenicity across multiple cellular compartments. We propose the 'thrombotic niche' as a conceptual, multi-compartment model encompassing mutant hematopoietic stem cells, hyperinflammatory myeloid effectors, hyperreactive platelets, platelet-leukocyte aggregates, and activated endothelium, but it remains a hypothesis-generating framework that lacks direct prospective clinical validation. Current cytoreductive strategies inadequately address this underlying biology, leaving substantial residual vascular risk. Emerging anti-inflammatory and anti-clonal strategies targeting interleukin-1 beta (IL-1β) (canakinumab), mutant-selective JAK2 inhibition, NLRP3 inflammasome blockade, and P-selectin-mediated adhesion are biologically plausible, but their ability to reduce thrombotic events in MPN remains unproven and should be viewed as hypothesis-generating rather than established clinical benefit. We conclude by outlining a translational research agenda integrating inflammation-aware risk stratification, niche-directed imaging, and spatial multi-omics to guide precision anti-inflammatory interventions in MPN.
2025-12-09 | Integrin-dependence of extramedullary erythropoiesis in the spleen of Jak2-V617F positive myeloproliferative neoplasm in mice.
The molecular mechanisms driving splenomegaly in myeloproliferative neoplasms (MPNs) remain poorly understood. Utilizing the Jak2-V617F knock-in mouse model, we investigated the role of β1- and β2-integrins in regulating spleen volume and spleen weight. The response to neutralizing antibodies against VLA-4 and the β2-integrin chain, as well as to isotype controls, was evaluated by serial intraindividual magnetic resonance imaging, by assessment of spleen weight and by analysis of the cellular composition of spleens. Short-term anti-VLA-4/β2-integrin treatment (applied on day 1 and evaluated at day 8) significantly reduced the spleen volume by 30% compared with the immunoglobulin G (IgG) control. At the cellular level, anti-integrin treatment led to a substantial 30% decrease in erythroblast counts and a 23% reduction in basophilic erythroblasts within the spleen, as compared with the isotype control. Furthermore, immunohistochemistry analysis of spleen sections revealed that CD71 (= Transferrin receptor protein 1) expression in spleen remained largely unchanged, whereas there was a clear reduction in Ter119 expression upon anti-integrin treatment. These data suggest that the substantial decrease in erythroblasts following anti-integrin treatment is a primary factor contributing to the overall reduction in spleen size. To study the spleen architecture, multiepitope ligand cartography (MELC) analysis of spleen sections was applied. This demonstrated that the spatial distribution of the marginal zone, red pulp, and white pulp remained unaltered upon anti-integrin treatment in JAK2-V617F knock-in mice. In summary, the present study identified a previously unrecognized role of the β1-integrin VLA-4 and of β2-integrin chains in extramedullary erythropoiesis of the spleen in JAK2-V617F-induced disease.
2025-11-19 | Impaired IL-10 Receptor Signaling Leads to Inflammation Induced Exhaustion in Hematopoietic Stem Cells.
Hematopoietic stem cells require tight regulation to rapidly initiate emergency hematopoiesis in response to pathogens, but chronic activation leads to proliferation induced exhaustion. Timely reentry into quiescence after inflammatory stimuli is essential for long term sustained HSC maintenance. We identify IL-10R signaling, an established negative feedback regulator in mature myeloid cells, as critical for returning HSCs to quiescence. IL-10R blockade prolongs HSC cycling and sustains activated transcriptional programs after acute inflammation. With chronic exposure, blockade increases cumulative divisions and accelerates aging hallmarks, including myeloid bias, loss of polarity, and functional defects, under conditions that do not otherwise exhaust HSCs when IL-10R signaling is intact. Jak2 V617F mutant HSCs resist the aging acceleration induced by blockade. Consistent with this resistance, IL-10R blocking antibody promotes Jak2 V617F clonal expansion and augments the myeloproliferative neoplasm phenotype. Together, these findings identify IL-10R signaling as a key coordinator of post inflammatory return to quiescence and suggest that modulating this axis could preserve HSCs and shape clonal hematopoiesis. Wadley et al. show that IL-10 receptor signaling restrains inflammation-induced hematopoietic stem cell cycling and exhaustion; its blockade prolongs cycling, accelerates aging-related decline, and selectively favors Jak2 V617F mutant HSCs, establishing IL-10 signaling as a critical regulator of inflammatory HSC exhaustion and malignant clonal evolution.
2025-07-02 | Cellular expression of PD-1, PD-L1 and CTLA-4 in patients with JAK2V617F mutated myeloproliferative disorders.
The acquired, somatic JAK2V617F mutation is the most common molecular aberration in patients with myeloproliferative neoplasms (MPN) and also significantly involved in the regulation of T cell immunity. PD-1, PD-L1 and CTLA-4 are key immune checkpoint regulators that are elevated in patients with solid tumors, infectious diseases and chronic inflammation. We aimed further investigating the significance of immune checkpoint expression in JAK2V617F positive MPN. The surface expression of PD-L1, PD-1 and CTLA-4 on peripheral blood leukocytes was determined by flow cytometry in 27 patients with JAK2V617F positive MPN and in a control group of 26 healthy individuals and analyzed by immune checkpoint and leukocyte subpopulation. In addition, the concentration of soluble PD-L1 (sPD-L1) in plasma was examined by ELISA. PD-1, PD-L1 and CTLA-4 are significantly overexpressed on the surface of granulocytes in JAK2 positive patients compared to the control group. Soluble PD-L1 (sPD-L1) is elevated in the plasma of JAK2 positive patients and increases with decreased renal function. In CD8+ T-cells and CD4+ T-cells there is a significant negative correlation between PD-1 expression or sPD-L1 concentration and their corresponding cell count. Our study shows a significant increase of immune checkpoint regulators on the cellular surface as well as soluble PD-L1 in JAK2 mutated patients compared to healthy individuals. Increased activation of the JAK2/STAT signaling pathway by JAK2V617F appears to be a mechanism of reduced immune activation in patients with MPN. Immune checkpoint inhibition might therefore represent a potential additional therapeutic target in this disease group.
2025-06-12 | IL-18 inhibition enlarges lesions, necrotic cores and thickens fibrous caps in Jak2 V617F clonal hematopoiesis-driven atherosclerosis.
Inflammasome activation promotes atherosclerosis in clonal hematopoiesis (CH). Active inflammasomes secrete both IL-1β and IL-18. Plasma IL-18 levels are elevated in Jak2 VF CH. Genetic deficiency of IL-18 has been shown to reduce atherosclerosis in non-CH murine models. However, whether IL-18 inhibition promotes atherosclerosis in control or Jak2 VF CH is unknown. Ldlr -/- mice were transplanted with bone marrow (BM) from Mx1-cre Jak2 VF (20%) and wild-type (80%) mice or with control BM, fed a Western-type diet (WTD) for 8, 10 or 16 weeks and administered control or IL-18 IgG from 4 weeks onwards. IL-18 antibody treatment increased plaque collagen content and cap thickness. Unexpectedly, IL-18 antibody treatment increased the size of early lesions and promoted formation of advanced lesions with large necrotic cores in Jak2 VF CH mice. IL-18 antibody treatment was associated with diminished interferon (IFN)-γ and AIM2 levels and reduced macrophage pyroptosis especially in Jak2 VF CH mice. However, IL-18 antibodies increased cleaved Caspase-3 and TUNEL + macrophages (indicating increased apoptosis) and reduced efferocytosis. Sc-RNA-seq analysis showed that IL-18 antibody treatment reduced expression of MHC class II genes, a marker of IFN-γ signaling, and of genes mediating efferocytosis ( Mertk and Axl) , in resident-like macrophage subpopulations in Jak2 VF CH mice. Consistently, IFN-γ injection increased Axl and Mertk expression in resident peritoneal macrophages. Despite improvements in collagen and fibrous cap thickness in Jak2 VF CH mice, IL-18 antibody treatment increased advanced necrotic lesions, reflecting a shift from pyroptotic to apoptotic cell death coupled with defective efferocytosis, events which were coordinated by reduced IFN-γ signaling. These findings indicate a mixed atherosclerosis phenotype resulting from IL-18 inhibition, advocating for alternative therapeutic strategies. Inhibition of IL-18 has been considered as a novel therapeutic approach to reduce atherosclerosis and stabilize atherosclerotic plaques. We show that IL-18 antibodies have adverse effects on atherosclerotic lesional necrosis, calling this approach into question. Inflammasome activation produces active IL-1 and IL-18 and worsens atherosclerosis in clonal hematopoiesis (CH) however the contribution of IL-18 is unknown. Antibody inhibition of IL-18 increased plaque collagen but also increased early lesion area and late lesions with large necrotic cores in Jak2 VF CH mice. There was a reversal of AIM2 inflammasome activation but a switch to apoptosis which along with reduced efferocytosis increased necrosisThese events appeared to be coordinated by reduced IFN-γ which increased collagen but also decreased expression of efferocytotic genes. Our studies call into question whether inhibition of IL-18 would stabilize plaques in CH.
cell therapies
2026-03-12 | Clinical Outcomes of Allogeneic Stem Cell Transplantation in Myelofibrosis - A Single Center Experience.
There is paucity of data on the outcomes of allogeneic stem cell transplantation (allo-SCT) for myelofibrosis, from developing countries. This is a retrospective analysis of patients undergoing allogeneic stem cell transplant for myelofibrosis at our center between January 1998 to December 2023. Thirty-four patients underwent allogeneic transplantation with a median age of 46 (19-68) years with 24 (70.6%) being males. The median dynamic international prognostic scoring system (DIPSS) Score was 3 (2-4). JAK2 was the most common driver mutation, in 10 (34.5%) patients. Majority of patients received reduced intensity conditioning with Fludarabine-Melphalan +/-total body irradiation (n=32) and all had peripheral blood grafts with donor source being matched sibling in 22 (64.7%), unrelated donor in 9 (26.5%) [7 full HLA match, one 9/10 HLA match and one 8/10 HLA match] and haploidentical in 3 (8.8%). The median CD34 cell dose infused was 9.9 (3.4-22) × 106/kg. The majority received calcineurin inhibitor + methotrexate (n=28) as Graft versus Host Disease (GVHD) prophylaxis. Two patients died before day 14 due to sepsis while 3 (9.3%) had primary graft failure. Neutrophil engraftment occurred in 29 patients (85.3%) at a median of 15 (range 8-25) days. Acute GVHD was noted in 20 (58.8%) patients with grade 3-4 GVHD in 13 (38.2%). Chronic GVHD was noted in 12 patients with 4 being extensive chronic GVHD as per revised Seattle criteria. On last follow up, 15 (44.1%) patients are alive while 19 have died. Allo-SCT for myelofibrosis is associated with reasonable cure rates, however strategies to reduce graft failure and GVHD are required.
2024-06-17 | A comparison between erythrocytapheresis and venesection for the treatment of JAK2-mutated polycythaemia.
JAK2-mutated polycythaemia vera (PV) is associated with reduced survival because of thrombotic events and haematological disease transformation. Therapeutic venesection has traditionally been used to lower haematocrit, but the technique of erythrocytapheresis has emerged over the last decade. To compare erythrocytapheresis with venesection as treatment for PV by assessing medical efficacy and financial viability. One hundred sixteen patients with PV who received red cell depletion therapy at Barwon Health between 2014 and 2021 were identified. The haematocrit drop after each session, interval between treatment times and number of sessions required to achieve a haematocrit <0.45 were compared with an independent t test. Thrombosis rates were compared with Pearson's chi-squared test. Cost-funding analysis was done by assessing the Weighted Inlier Equivalent Separation and National Weighted Activity Unit funding models. Patients treated with erythrocytapheresis achieved a greater haematocrit drop each treatment session (0.075 vs 0.03, P < 0.01), required fewer sessions to achieve a haematocrit <0.45 (1 vs 4, P < 0.01) and experienced fewer thrombotic complications (8.7% vs 32.1%, P = 0.02) than those treated with venesection. Cost-funding analysis demonstrated that erythrocytapheresis was more financially viable with a surplus of AU$297 per session compared to a deficit of AU$176 with venesection. Even if funding for venesection is increased, the cost of erythrocytapheresis may be mitigated by a lower number of procedures required per year (3.8 vs 5.3, P < 0.01). Erythrocytapheresis is more efficacious than venesection for the treatment of PV and is accompanied by rapid reductions in haematocrit and reduced thrombotic complications.
2023-12-16 | JAK2 R683S Mutation Resulting in Dual Diagnoses of Chronic Eosinophilic Leukemia and Myelodysplastic/Myeloproliferative Overlap Syndrome.
A 66-year-old male presented with hypereosinophilia, thrombocytosis, extensive thrombosis refractory to direct oral anticoagulant therapy, and evidence of end-organ damage, including rash, splenic infarcts, and pulmonary infiltrates. Bone marrow biopsy revealed myeloid malignancy consistent with both chronic eosinophilic leukemia and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) with SF3B1 mutation and thrombocytosis. Next-generation sequencing of the patient's eosinophils and neutrophil compartments revealed pathologic variants in EZH2 and SF3B1 in addition to a noncanonical JAK2 R683S mutation that has not been previously described in myeloproliferative disorders or other chronic myeloid neoplasms. These mutations were not present in the patient's lymphoid cell fraction, suggesting that the hematopoietic malignancy arose in a myeloid-committed progenitor cell. Based on this case and previous work from our group, we propose that noncanonical JAK2 mutations may permit signal transduction that biases toward eosinophilic differentiation in chronic myeloid neoplasms. Although the patient's blood counts initially responded to ruxolitinib and hydroxyurea, the response was not durable. Early referral for allogenic bone marrow transplant appears necessary to prevent long-term complications and disease progression in myeloid neoplasms with clonal hypereosinophilia driven by noncanonical JAK2 mutations.
2019-04-17 | Functional interdependence of hematopoietic stem cells and their niche in oncogene promotion of myeloproliferative neoplasms: the 159th biomedical version of "it takes two to tango".
The role of stem cells in normal and neoplastic hematopoiesis is well established. However, neither normal nor neoplastic hematopoietic stem cells (HSCs) develop in isolation and accumulating evidence indicates that a critical developmental role is played by the perivascular "niche." The cellular, humoral, and cell surface contacts that provide the proper environment for HSC survival, proliferation, and differentiation are becoming increasingly better understood. A number of studies have established that endothelial cells (ECs), several types of perivascular stromal cells, and megakaryocytes (MKs) provide several cell surface and secreted molecules required for HSC development. Accumulating evidence also indicates that the normal stem cell niche is altered in patients with hematological neoplasms and that the "neoplastic niche" plays an important role in promoting malignant and suppressing normal blood cell development in such patients. To explore this concept in the myeloproliferative neoplasms (MPNs), we employed a murine model to determine the effects of Jak2V617F, an oncogene found in a majority of such patients, in marrow ECs and MKs and their effect on promoting neoplastic and suppressing normal hematopoiesis. We found that Jak2V617F has profound effects on both cell types, which together are critical for the growth advantage and radioresistance shown by Jak2V617F-bearing HSCs. Such findings should provide new approaches to the treatment of patients with MPNs.
2018-12-11 | MLL-PTD in a 13-year-old patient with blast phase myeloproliferative neoplasm: A case report.
The risk of leukemic transformation in myeloproliferative neoplasm (MPN) has been increasing with time. Partial Tandem Duplications of the MLL gene (MLL-PTD) has been reported in de novo acute myeloid leukemia (AML), but not in MPN blast phase. The post-MPN AML developed adverse clinical outcomes, which showed no noticeable improvement over the past 15 years. Therefore, the mechanisms and therapeutic approaches of post-MPN AML need to be deeply studied. In this study, we present a JAK2V617F positive MPN patient who experienced fatigue and splenomegaly, transforming into JAK2V617F negative AML. A diagnosis of acute monocytic leukemia was made in MPN blast phase. The patient received chemotherapy and allogeneic hematopoietic stem cell transplantation (Allo-SCT). The patient achieved complete remission twice, but relapsed twice. Relapse-free survival was only 3 months. She died about 24 months after her diagnosis. MLL-PTD occurs in the progression of JAK2V617F positive MPN into JAK2V617F negative AML, which may be a novel mechanism of MPN blast phase and helpful for post-MPN AML diagnosis. Allo-SCT may be a good choice for post-MPN AML with MLL-PTD. More therapeutic strategies need to be explored for a better prognosis in these patients.
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2025-05-28 | CRISPR/Cas9-Based Modeling of JAK2 V617F Mutation in K562 Cells Reveals Enhanced Proliferation and Sensitivity to Therapeutic Agents.
The Janus kinase 2 (JAK2) protein fulfills an important role in hematopoiesis via the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway, as it provides the genetic driver of BCR::ABL1-negative myeloproliferative neoplasms (MPNs), which are clinically manifested as polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The most common cause of MPNs is the mutation of JAK2 V617F in the JAK2 gene, which results in increased cell proliferation. However, both the pathogenesis and treatment regimen of BCR::ABL1-negative MPNs remain poorly understood. The aim of the present study was to establish K562 cell lines with a point mutation in exon 14 (JAK2p.V617F) using CRISPR/Cas9 technology. The modified JAK2 V617F cell lines were examined for the gene mutation using droplet digital PCR (DDPCR), and the presence of the mutation was confirmed by DNA sequencing. Modified cells were characterized by measuring JAK2 gene expression and the extent of cell proliferation. Interferon α2a (IFN-α2a) and arsenic trioxide were also administered to the cells to explore their potential effects. The JAK2 V617F-mutated cells were found to exhibit a higher level of JAK2 gene expression compared with the wild type. Interestingly, a significant increase in the proliferation rate was observed with the modified cells compared with the wild type cells (p < 0.001), as assessed from the JAK2 gene expression levels. Furthermore, the treatments with IFN-α2a and arsenic trioxide led to the preferential suppression of the cell proliferation rate of the K562 expressing mutant JAK2 cells compared with the wild type cells, and this suppression occurred in a dose-dependent manner(p < 0.01). Moreover, the modified cells were able to differentiate into megakaryocyte-like cells following stimulation with phorbol 12 myristate 13 acetate (PMA). Taken together, the results of the present study have shown that the CRISPR/Cas9-modified JAK2 V617F model may be used as a disease model in the search of novel therapies for MPNs.
2025-02-28 | Suppressed activation of the IRF7 and TLR9 by JAK2V617F gold nanoparticles.
Philadelphia chromosome-negative myeloproliferative neoplasms (Ph-MPNs) are characterized by the overproduction of myeloid cells and a lack of response to cytokine signaling, along with genomic instability and the accumulation of nucleic acids in the cytoplasm. In this study, we investigated the effects of oligonucleotide-gold nanoparticle conjugates (ON-GNPs) targeting JAK2 or JAK2V617F mRNAs on nucleic acid-sensing pathways in HEL, SET2, and K562 cell lines. We evaluated changes in gene expression related to TLR9 and cGAS/STING pathways, RAGE/TLR9 receptor dynamics, and inflammatory cytokine release over short-term (0.5-2 h) and long-term (24-72 h) exposures. Our results demonstrated that ON-GNPs transiently suppressed TLR9, IRF7, and NFKB1 expression during the short term, followed by significant upregulation after 24 h, persisting up to 72 h. Notably, JAK2V617F-targeting ON-GNPs induced heightened IRF7 activation in HEL and SET2 cells after 24 h without affecting TLR9/RAGE expression. Additionally, IL-8 secretion increased in HEL and SET2 culture media after 72 h, correlating with interferon pathway activation. This study reveals that complementary ON-GNPs can modulate nucleic acid-sensing pathways, suppressing IL-8 and inflammatory signaling in the short term while inducing delayed activation of TLR9 and IRF7 in the presence of JAK2V617F. These findings provide a promising foundation for developing ON-GNP-based therapeutic strategies to manage inflammation and disease progression in Ph-MPNs.
2024-10-01 | Differential modulation of mutant CALR and JAK2 V617F-driven oncogenesis by HLA genotype in myeloproliferative neoplasms.
It has been demonstrated previously that human leukocyte antigen class I (HLA-I) and class II (HLA-II) alleles may modulate JAK2 V617F and CALR mutation (CALRmut)-associated oncogenesis in myeloproliferative neoplasms (MPNs). However, the role of immunogenetic factors in MPNs remains underexplored. We aimed to investigate the potential involvement of HLA genes in CALRmut+ MPNs. High-resolution genotyping of HLA-I and -II loci was conducted in 42 CALRmut+ and 158 JAK2 V617F+ MPN patients and 1,083 healthy controls. A global analysis of the diversity of HLA-I genotypes revealed no significant differences between CALRmut+ patients and controls. However, one HLA-I allele (C*06:02) showed an inverse correlation with presence of CALR mutation. A meta-analysis across independent cohorts and healthy individuals from the 1000 Genomes Project confirmed an inverse correlation between the presentation capabilities of the HLA-I loci for JAK2 V617F and CALRmut-derived peptides in both patients and healthy individuals. scRNA-Seq analysis revealed low expression of TAP1 and CIITA genes in CALRmut+ hematopoietic stem and progenitor cells. In conclusion, the HLA-I genotype differentially restricts JAK2 V617F and CALRmut-driven oncogenesis potentially explaining the mutual exclusivity of the two mutations and differences in their presentation latency. These findings have practical implications for the development of neoantigen-based vaccines in MPNs.
2023-03-14 | An arginase1- and PD-L1-derived peptide-based vaccine for myeloproliferative neoplasms: A first-in-man clinical trial.
Arginase-1 (ARG1) and Programed death ligand-1 (PD-L1) play a vital role in immunosuppression in myeloproliferative neoplasms (MPNs) and directly inhibit T-cell activation and proliferation. We previously identified spontaneous T-cell responses towards PD-L1 and ARG1 derived peptide epitopes in patients with MPNs. In the present First-in-Man study we tested dual vaccinations of ARG1- derived and PD-L1-derived peptides, combined with Montanide ISA-51 as adjuvant, in patients with Janus Kinase 2 (JAK2) V617F-mutated MPN. Safety and efficacy of vaccination with ARG1- derived and PD-L1-derived peptides with montanide as an adjuvant was tested in 9 patients with MPN The primary end point was safety and toxicity evaluation. The secondary end point was assessment of the immune response to the vaccination epitope (www.clinicaltrials.gov identifier NCT04051307). The study included 9 patients with JAK2-mutant MPN of which 8 received all 24 planned vaccines within a 9-month treatment period. Patients reported only grade 1 and 2 vaccine related adverse events. No alterations in peripheral blood counts were identified, and serial measurements of the JAK2V617F allelic burden showed that none of the patients achieved a molecular response during the treatment period. The vaccines induced strong immune responses against both ARG1 and PD-L1- derived epitopes in the peripheral blood of all patients, and vaccine-specific skin-infiltrating lymphocytes from 5/6 patients could be expanded in vitro after a delayed-type hypersensitivity test. In two patients we also detected both ARG1- and PD-L1-specific T cells in bone marrow samples at the end of trial. Intracellular cytokine staining revealed IFNγ and TNFγ producing CD4+- and CD8+- T cells specific against both vaccine epitopes. Throughout the study, the peripheral CD8/CD4 ratio increased significantly, and the CD8+ TEMRA subpopulation was enlarged. We also identified a significant decrease in PD-L1 mRNA expression in CD14+ myeloid cells in the peripheral blood in all treated patients and a decrease in ARG1 mRNA expression in bone marrow of 6 out of 7 evaluated patients. Overall, the ARG1- and PD-L1-derived vaccines were safe and tolerable and induced strong T-cell responses in all patients. These results warrant further studies of the vaccine in other settings or in combination with additional immune-activating treatments.
2022-01-05 | Tmprss6-ASO as a tool for the treatment of Polycythemia Vera mice.
Polycythemia Vera (PV) is a chronic myeloproliferative neoplasm resulting from an acquired driver mutation in the JAK2 gene of hematopoietic stem and progenitor cells resulting in the overproduction of mature erythrocytes and abnormally high hematocrit, in turn leading to thromboembolic complications. Therapeutic phlebotomy is the most common treatment to reduce the hematocrit levels and consequently decrease thromboembolic risk. Here we demonstrate that, by using the iron restrictive properties of the antisense oligonucleotides against Tmprss6 mRNA, we can increase hepcidin to achieve effects equivalent to therapeutic phlebotomy. We provide evidence that this less invasive approach could represent an additional therapeutic tool for the treatment of PV patients.
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Drug Discovery Landscape
2 orphan drug designations for Myeloid/lymphoid neoplasms associated with eosinophilia and abnormality of PDGFRA, PDGFRB, FGFR1 or JAK2, including 1 approved therapy.
2 orphan drug designations for Myeloid/lymphoid neoplasms associated with eosinophilia and abnormality of PDGFRA, PDGFRB, FGFR1 or JAK2, including 1 approved therapy.
Drug | Therapy type | Regulator | Orphan designation | Approval | Sponsor |
|---|---|---|---|---|---|
Pemigatinib | small molecules | EMA | 2019-10-17 | — | Incyte Biosciences Distribution B.V. |
pemigatinib [Pemazyre] | small molecules | FDA | 2019-08-21 | 2022-08-26 | Incyte Corporation |
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