bims-tremyl Biomed News
on Therapy resistance biology in myeloid leukemia
Issue of 2025–02–09
39 papers selected by
Paolo Gallipoli, Barts Cancer Institute, Queen Mary University of London



  1. Blood. 2025 Feb 07. pii: blood.2024026700. [Epub ahead of print]
      Venetoclax combined with intensive chemotherapy shows promise for untreated acute myeloid leukemia (AML), but its integration with the '7+3' regimen remains underexplored. In a phase 1b study (NCT05342584), we assessed the safety and efficacy of venetoclax with daunorubicin and cytarabine in newly diagnosed AML patients. Thirty-four patients (median age 59 years; 62% non-white) received venetoclax at escalating durations (8, 11, or 14 days). Adverse events included febrile neutropenia (100%), sepsis (29%), and enterocolitis (23.5%), with no induction deaths. Median recovery times for neutrophils (>1.0K/uL) and platelets (>100K/uL) were under 30 days. Composite complete remission (CRc) was achieved in 85.3% of patients, with 86.2% being measurable residual disease (MRD)-negative. Responses spanned all ELN2022 risk categories. With a median follow-up of 9.6 (2-20) months, median duration of response, event-free survival and overall survival were not reached. Venetoclax (400 mg) combined with '7+3' chemotherapy was safe and effective in achieving MRD-negative remissions across all durations. Ven dose optimization is being explored in the expansion phase of this trial. Future multicenter studies should confirm our findings.
    DOI:  https://doi.org/10.1182/blood.2024026700
  2. Blood Adv. 2025 Feb 06. pii: bloodadvances.2024013744. [Epub ahead of print]
      Fitness assessment in patients with acute myeloid leukemia (AML) is critical to deliver the right therapy to the right patient. While several scoring systems are available to aid in determining fitness, the absence of validation studies has resulted in the lack of universally accepted assessment procedures. This limitation, combined with the increasing availability of novel agents expanding the spectrum of less-intensive options, has introduced additional complexity to the fitness assessment process. In this evolving context, fitness should reflect eligibility for a specific treatment among the several available, rather than a generic binary classification of eligibility for intensive chemotherapy. Moreover, the growing emphasis on patient-centered care, further highlights the importance of integrating quality of life, patients' preferences, patients' self-reported physical and social functioning status, social support, and early integration of palliative care into the assessment framework. A modern interpretation of fitness assessment should incorporate a comprehensive evaluation that extends beyond traditional clinical and biological disease characteristics. Thus, fitness assessment in patients with AML represents only one piece of a larger puzzle, encompassing the patient's overall capacity to sustain and benefit from a specific therapeutic program.
    DOI:  https://doi.org/10.1182/bloodadvances.2024013744
  3. Am J Hematol. 2025 Feb 04.
      Mutations in nucleophosmin 1 (NPM1) are diseased-defining genetic alterations encountered in approximately one-third of cases of acute myeloid leukemia (AML). A mutation in NPM1 confers a more favorable prognosis; however, clinical outcomes of NPM1-mutated AML (NPM1mut AML) are diverse due to the heterogeneity of disease biology, patient characteristics, and treatment received. Research over the last two decades has dramatically expanded our understanding of the biology of NPM1mut AML and led to the development of new therapeutic approaches and strategies for monitoring measurable residual disease (MRD). Here, we review NPM1mut AML with a practical focus on the current treatment landscape, the role of MRD in guiding management, and emerging therapies, including menin inhibitors.
    Keywords:  AML; AML‐molecular diagnosis & therapy; dysplasias; neoplasia‐myeloid leukemias
    DOI:  https://doi.org/10.1002/ajh.27600
  4. Blood Adv. 2025 Feb 04. pii: bloodadvances.2024014767. [Epub ahead of print]
      Whether patients with acute myeloid leukemia (AML) harboring Nucleophosmin mutations (NPM1mut) with measurable residual disease (MRD) should undergo allogeneic stem cell transplantation (alloSCT) in complete remission (CR) remains subject of debate. This study aimed to assess whether the presence of bone marrow (BM) NPM1mut MRD, detected using a RT-qPCR assay with a sensitivity of 10-5, could influence the benefit derived from alloSCT. Data from four German transplantation centers were analyzed including 174 AML NPM1mut patients who underwent a first alloSCT between 2011-2022. Among 122 patients transplanted in complete remission (CR), pre-alloSCT MRD was positive in 54%. After alloSCT, the cumulative rate of BM MRD negativity increased from 65% by day +30 to 73% by day +100, with FLT3-ITD and ELN risk profile significantly impacting on MRD conversion rate at day +30. No significant difference in leukemia-free survival (LFS) and overall survival (OS) based on pre-transplant MRD status (3y LFS MRD+ 60% vs MRD- 74%, HR 1.5, p=0.28; 3y OS MRD+ 68% vs MRD- 78%, HR 1.42, p=0.39) was observed. Outcomes between MRD persistence and molecular relapse did not differ (p=0.8). Whereas adverse molecular risk features (HR 4.69, p=0.003) and relapsed/refractory disease (HR 2.83/3.59, p=0.005/0.001) were associated with unfavorable prognosis, administration of post-transplant maintenance improved survival in multivariable analysis (HR 0.48, p=0.06). Our findings suggest that in patients with NPM1mut AML MRD positivity as assessed per qPCR at time of transplant does not impact posttransplant outcomes of NPM1mut AML.
    DOI:  https://doi.org/10.1182/bloodadvances.2024014767
  5. Blood. 2025 Feb 05. pii: blood.2024024475. [Epub ahead of print]
      X-linked sideroblastic anemia (XLSA) in carrier females of ALAS2 mutations is not uncommon. We describe unique features and genotype/phenotype correlations in XLSA females and evaluate the contributions of X-chromosome skewing and clonal hematopoiesis, emphasizing the importance of distinguishing it from myelodysplastic syndromes with ring sideroblasts.
    DOI:  https://doi.org/10.1182/blood.2024024475
  6. Blood. 2025 Feb 05. pii: blood.2024026040. [Epub ahead of print]
      Differentiation arrest and dependence on oxidative metabolism are features shared among genetically diverse acute myeloid leukemias (AML). A phenotypic CRISPR-Cas9 screen in AML identified dependence on phosphoseryl-tRNA kinase (PSTK), an atypical kinase required for the biosynthesis of all selenoproteins. In vivo, PSTK inhibition (PSTKi) impaired AML cell growth and leukemic stem cell self-renewal. Notably, timed pharmacologic PSTKi effectively targeted chemo-resistant AML in murine and patient-derived xenograft models, showing selectivity for malignant cells over normal hematopoietic cells. Mechanistically, PSTKi-induced reactive oxygen species (ROS) triggering mitochondrial DNA release into the cytosol and activated cGAS-STING. This activation in turn disrupted iron metabolism augmenting ROS generation and amplifying ferroptosis. Together, these findings reveal a self-reinforcing PSTK-cGAS-STING-ROS loop culminating in an oxidative crisis and ferroptotic cell death of leukemic stem cells. The data highlight the potential for augmenting standard cancer chemotherapies using timed metabolic intervention to eliminate chemopersisting cells and thereby impede disease relapse.
    DOI:  https://doi.org/10.1182/blood.2024026040
  7. Adv Anat Pathol. 2025 Feb 03.
      The International Consensus Classification (ICC) of myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) expands on the work of prior classifications to refine the diagnostic criteria for MDS and AML and to identify specific genetic disease subtypes. This review summarizes the approach to the diagnosis of MDS and AML from the ICC perspective. For MDS, the significance of detecting mutations in SF3B1, usually associated with ring sideroblasts, as well as the poor prognosis of mutations of TP53 are now included. For AML, new genetic categories are included, and the classification now incorporates additional clinically significant gene mutations by recognizing AML with TP53 mutation and AML with mutations in genes associated with prior therapy or MDS. Finally, the new category of MDS/AML is introduced for adult patients without recurrent de novo genetic abnormalities with 10% to 19% peripheral blood or bone marrow blasts that allow for more treatment flexibility based on clinical findings. While the increase in genetic categories and changes in blast cell requirements can be confusing, a stepwise approach is provided to allow easy use of the classification.
    DOI:  https://doi.org/10.1097/PAP.0000000000000485
  8. Bone Marrow Transplant. 2025 Feb 05.
      Post-transplant cyclophosphamide (PTCY) is increasingly used as effective graft-versus-host disease (GvHD) prophylaxis in allogeneic hematopoietic-cell transplantation (allo-HCT). However, PTCY is associated with toxicities. Whether patients with specific comorbidities are more vulnerable to cyclophosphamide-induced toxicity is unclear. We retrospectively evaluated the impact of individual organ dysfunctions for non-relapse mortality (NRM) risk and overall survival (OS) among 5888 adults who underwent PTCY-based allo-HCT for acute myeloid leukemia between 2010 and 2023. In multivariable analyses 5 of the comorbidities (renal, moderate/severe hepatic, cardiac including arrhythmia/valvular disease, severe pulmonary, infection) were independently associated with adverse NRM and OS without influencing relapse rate. A simplified model using the absence (n = 4390), presence of 1 (n = 1229) or presence of 2 or 3 (n = 269) of the comorbidities which were determined individually to contribute to NRM stratified patients into 3 NRM risk (16.2% vs. 21.6% vs. 36%, retrospectively) and OS categories (64% vs. 56% vs. 36.4%, retrospectively). In Cox model, recipients with 2 or 3 comorbidities had an increased hazard ratio for NRM of 2.38 (95% confidence interval [CI], 1.89-3) and for OS of 1.96 (95% CI 1.64-2.33). Whether patients with concomitant diagnoses, as determined here, may benefit from a reduced PTCY dose remains to be evaluated in prospective clinical trials.
    DOI:  https://doi.org/10.1038/s41409-025-02514-4
  9. Cell Rep Med. 2025 Jan 29. pii: S2666-3791(25)00006-0. [Epub ahead of print] 101933
      Approximately 30% of patients with chronic myelomonocytic leukemia (CMML) undergo transformation to a chemo-refractory blastic phase (BP-CMML). Seeking novel therapeutic approaches, we profiled blast transcriptomes from 42 BP-CMMLs, observing extensive transcriptional heterogeneity and poor alignment to current acute myeloid leukemia (AML) classifications. BP-CMMLs display distinctive transcriptomic profiles, including enrichment for quiescence and variability in drug response signatures. Integrating clinical, immunophenotype, and transcriptome parameters, Random Forest unsupervised clustering distinguishes immature and mature subtypes characterized by differential expression of transcriptional modules, oncogenes, apoptotic regulators, and patterns of surface marker expression. Subtypes differ in predicted response to AML drugs, validated ex vivo in primary samples. Iteratively refined stratification resolves a classification structure comprising five subtypes along a maturation spectrum, predictive of response to novel agents including consistent patterns for receptor tyrosine kinase (RTK), cyclin-dependent kinase (CDK), mechanistic target of rapamycin (MTOR), and mitogen-activated protein kinase (MAPK) inhibitors. Finally, we generate a prototype decision tree to stratify BP-CMML with high specificity and sensitivity, requiring validation but with potential clinical applicability to guide personalized drug selection for improved outcomes.
    Keywords:  CMML; MDS/MPN; blast phase; leukemic transformation; secondary AML
    DOI:  https://doi.org/10.1016/j.xcrm.2025.101933
  10. Nat Commun. 2025 Feb 04. 16(1): 1358
      Sphingolipid, ceramide for example, plays an essential role in regulating cancer cell death. Defects in the generation and metabolism of ceramide in cancer cells contribute to tumor cell survival and resistance to chemotherapy. Ceramide Transfer Protein (CERT) determines the ratio of ceramide and sphingomyelin in cells. Targeting CERT sensitizes solid cancer cells to chemotherapy. However, whether targeting CERT to induce ceramide accumulation thereby improving AML therapy efficiency remains elusive. Here, we show that knocking down CERT inhibits the growth and promotes the apoptosis of AML cells carrying FLT3-ITD mutation. Combining CERT inhibitor with FLT3 inhibitor exhibits synergistic effects on FLT3-ITD mutated acute myeloid leukemia (AML) cells. Additionally, co-treatment of HPA-12 and Crenolanib is effective in FLT3-ITD+ and FLT3-TKD+ AML patients. The synergistic effects are found to be mediated by the endoplasmic reticulum stress-GRP78/ATF6/CHOP axis and mitophagy. Our data provide an effective strategy to enhance the efficacy of FLT3 inhibitors in AML.
    DOI:  https://doi.org/10.1038/s41467-025-56520-7
  11. NPJ Precis Oncol. 2025 Feb 03. 9(1): 34
      Murine double minute 2 (MDM2) inhibitors have shown promising activity in TP53-wild type tumors and are under active investigation across a spectrum of malignancies. Herein, we report a 51-year-old female with MDM2-amplified, TP53-wild type adenoid cystic carcinoma who was treated with a MDM2 inhibitor and developed persistent pancytopenia despite drug discontinuation. Her pancytopenia was associated with 20 distinct pathogenic TP53 mutations in peripheral blood and bone marrow not present in drug-resistant tumor tissue. Plasma TP53 mutations were similarly detected among 4 other patients treated at our institution, with the number of mutations correlating strongly with duration of treatment. This case suggests that MDM2 inhibitors are associated with TP53 clonal hematopoiesis, which may confer a risk of subsequent myeloid malignancy. As multiple MDM2 inhibitor trials are ongoing, our findings underscore the need for further investigation into the potential long-term deleterious effects of these inhibitors in the hematopoietic stem and progenitor compartment.
    DOI:  https://doi.org/10.1038/s41698-025-00823-x
  12. bioRxiv. 2025 Jan 22. pii: 2025.01.19.633759. [Epub ahead of print]
      Patients with Acute Myeloid Leukemia (AML) subtypes, acute erythroleukemia and acute megakaryocytic leukemia (M6 and M7 AMLs, respectively) have a median survival of only a few months with no targeted effective treatment. Our gene expression analysis using the Cancer Cell Line Encyclopedia and CRISPR screen from DepMap showed that M6/M7 AMLs have high levels of the transcription factor GATA1 and depend on GATA1 for survival. While GATA1 was shown to support AML cell proliferation and resistance to chemotherapy, GATA1 has long been considered "undruggable". Here, we identify the small molecule N-(4-hydroxyphenyl)retinamide (4-HPR, Fenretinide) as a novel GATA1 targeting agent in M6 and M7 AML cells, with nM to low μM concentrations of 4-HPR causing loss of GATA1. In M6 AML OCIM1 cells, knock-down of GATA1 induced cytotoxicity similarly to low doses 4-HPR while overexpression of GATA1 significantly protected cells from 4-HPR-induced cytotoxicity. In M6 AML cells, 4-HPR synergized with the current standard-of-care (SOC), Azacytidine plus Venetoclax, overcoming cell resistance to the drugs. As single-agent, 4-HPR outperformed SOC. 4-HPR is a synthetic derivative of vitamin A, and numerous clinical trials have supported its safe profile in cancer patients; therefore, targeted use of 4-HPR against M6 and M7 AMLs may represent a novel therapeutic breakthrough.
    Key Points: - Fenretinide (4-HPR) targets the transcription factor GATA1, which was previously thought to be "undruggable" and induces GATA1 loss.- M6 and M7 Acute Myeloid Leukemias (AML) have enriched expression of GATA1 and they can be considered GATA1 positive.- Loss of GATA1 contributes significantly to 4-HPR cytotoxicity in M6 OCIM1 cells.- 4-HPR treatment overcomes chemotherapeutic resistance in M6 Acute Myeloid Leukemia cells, synergizes with standard-of-care and outperforms standard-of-care as a single agent.
    DOI:  https://doi.org/10.1101/2025.01.19.633759
  13. Nat Commun. 2025 Feb 01. 16(1): 1253
      We reported that an acquired miR-142 deficit transforms chronic phase (CP) chronic myeloid leukemia (CML) leukemic stem cells (LSCs) into blast crisis (BC) LSCs. Given the role of miR-142 in the development and activity of the immune system, we postulated that this deficit also promotes LSC immune escape. Herein, we report on IL-6-driven miR-142 deficit occurring in T cells during BC transformation. In CML murine models, miR-142 deficit impairs thymic differentiation of lymphoid-primed multipotent progenitors (LMPP) into T cells and prevents T cells' metabolic reprogramming, thereby leading to loss of T cells and leukemia immune escape. Correcting miR-142 deficit with a miR-142 mimic compound (M-miR-142), alone or in combination with immune checkpoint antibodies, restores T cell number and immune activity, leading to LSC elimination and prolonged survival of BC CML murine and patient-derived xenograft models. These observations may open new therapeutic opportunities for BC CML and other myeloid malignancies.
    DOI:  https://doi.org/10.1038/s41467-025-56383-y
  14. Blood. 2025 Feb 07. pii: blood.2023023787. [Epub ahead of print]
      Although described more than a decade ago, the mechanism by which the JAK2 46/1 haplotype increases the risk of developing JAK2-mutated myeloproliferative neoplasms (MPN) remains unexplained. Inflammation and immunity are linked to MPN development and thus could be relevant to the mechanism by which 46/1 mediates its effect. Here, we show that PD-L1 expression is elevated in 46/1 haplotype both in healthy carriers and CD34+ cells from MPN patients. Using circular chromosome conformation capture (4C-seq) we observed that PD-L1 and the neighboring PD-L2 loci physically interact with JAK2 in a manner that differs between 46/1 and non-risk haplotypes. CRISPR/Cas9 genome editing identified a region within JAK2 intron 2 that influences both JAK2 and PD-L1 expression. We suggest that increased PD-L1 expression may be relevant to the mechanism by which 46/1 leads to an increased inherited risk of developing MPN.
    DOI:  https://doi.org/10.1182/blood.2023023787
  15. J Pathol. 2025 Feb 05.
      This study investigated the clonal evolution of chronic myelomonocytic leukemia (CMML) progression to secondary acute myeloid leukemia (sAML) by next-generation sequencing and pyrosequencing for variant allele frequency (VAF) of gene mutations and SNP microarray for copy neutral loss of heterozygosity (CN-LOH) in 38 paired samples from CMML/sAML patients of Taiwanese origin. The median interval between CMML and sAML samples collection was 14.9 months (1.0-89.6). RUNX1 (57%), TET2 (46%), SRSF2 (37%), and ASXL1 (28%) mutations were frequent at CMML diagnosis. Baseline VAF in epigenetic regulator genes was high (>35%) in 83% of mutational events at the CMML phase, remained stable in 78% (VAF changes <10%), and increased in 20% (increased VAF > 10%) during progression to sAML. Transcription factor genes showed high VAF (>35%) in 51% at the CMML phase, and stable VAF in 60% during progression. VAF of spliceosome genes was high (>35%) in 70% at CMML phase, and stable in 61% during progression. Activated signaling genes exhibited acquisition or loss during progression. TET2 mutations were often founding clones, and SRSF2, ASXL1, DNMT3A, EZH2, or spliceosome genes also acted as ancestral mutations. RUNX1 mutations were typically later events and occasionally ancestral hits or germline mutations. Acquisition of cytogenetic changes, signaling pathways genes (PTPN11, FLT3, NRAS, CBL), or AML-defined genes (NPM1, CEBPA, CBFB::MYH11) by linear or branching evolution occurred during sAML progression. CN-LOH was noted in EZH2, CBL, TET2, and DNMT3A genes. CEBPA mutation and concurrent biallelic TET2 with NRAS mutations at CMML diagnosis were risk factors for time to AML progression and overall survival. A characteristic ASXL1MT/RUNX1MT/SpliceosomeMT/signalingWT genetic profile was associated with monocyte counts of 0.5-1.0 × 109/l. This study highlights the complexity and heterogeneity of dynamic changes in clonal architecture during CMML progression, emphasizing its importance in pathogenesis, phenotype, risk stratification, and therapeutic strategy. © 2025 The Pathological Society of Great Britain and Ireland.
    Keywords:  acute myeloid leukemia; allele frequency; chronic myelomonocytic leukemia; clonal evolution; next‐generation sequencing; paired‐sample analyses
    DOI:  https://doi.org/10.1002/path.6396
  16. bioRxiv. 2025 Jan 23. pii: 2025.01.23.634563. [Epub ahead of print]
      Hematopoiesis changes to adapt to the physiology of development and aging. Temporal changes in hematopoiesis parallel age-dependent incidences of blood diseases. Several heterochronic regulators of hematopoiesis have been identified, but how the master transcription factor (TF) circuitry of definitive hematopoietic stem cells (HSCs) adapts over the lifespan is unknown. Here, we show that expression of the ETS family TF Erg is adult-biased, and that programmed upregulation of Erg expression during juvenile to adult aging is evolutionarily conserved and required for complete implementation of adult patterns of HSC self-renewal and myeloid, erythroid, and lymphoid differentiation. Erg deficiency maintains fetal transcriptional and epigenetic programs, and persistent juvenile phenotypes in Erg haploinsufficient mice are dependent on deregulation of the fetal-biased TF Hmga2 . Finally, Erg haploinsufficiency in the adult results in fetal-like resistance to leukemogenesis. Overall, we identify a mechanism whereby HSC TF networks are rewired to specify stage-specific hematopoiesis, a finding directly relevant to age-biased blood diseases.
    SUMMARY: The hematopoietic system undergoes a process of coordinated aging from the juvenile to adult states. Here, we find that expression of ETS family transcription factor Erg is temporally regulated. Impaired upregulation of Erg during the hematopoietic maturation results in persistence of juvenile phenotypes.
    DOI:  https://doi.org/10.1101/2025.01.23.634563
  17. Fam Cancer. 2025 Jan 31. 24(1): 20
      Germline variants in RUNX1 and DDX41 are well-established contributors to hereditary myeloid neoplasms and are increasingly recognized as critical predisposing factors in the developing myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). This case report details a 51-year-old male diagnosed with MDS with excess blasts-1 (MDS-EB1), who harbored a rare combination of pathogenic germline variants in RUNX1 and a novel potentially pathogenic variant in DDX41 variant, alongside a somatic DDX41 mutation. The coexistence of these germline variants highlights the genetic complexity underlying hereditary myeloid neoplasms and reinforces the necessity of comprehensive genomic testing to ensure accurate diagnosis and informed clinical management. The interplay between RUNX1 and DDX41 variants may drive leukemogenesis, with the germline RUNX1 variant potentially fostering a cellular environment that enables the acquisition of somatic DDX41 mutations, leading to hematological malignancies. Conversely, the germline DDX41 variant may disrupt hematopoiesis and, when combined with RUNX1 dysfunction, contribute to disease progression. This case underscores the importance of screening germline variants in patients with myeloid neoplasms. It emphasizes the need to confirm the origin of these variants in non-hematopoietic tissues, such as fibroblasts (gold standard), to avoid misinterpretation caused by clonal hematopoiesis. Further research is warranted to elucidate the molecular mechanisms driving the interaction between RUNX1 and DDX41 variants and their collective impact on disease progression, treatment outcomes, and familial risk.
    Keywords:  Diagnosis; Germ-line variants; Myelodysplastic syndrome; Prognosis
    DOI:  https://doi.org/10.1007/s10689-025-00443-1
  18. Exp Hematol. 2025 Jan 30. pii: S0301-472X(25)00020-7. [Epub ahead of print] 104729
      Recently, human CD34+ hematopoietic stem cells (HSCs) have been purified to a frequency of approximately 1 in 3 cells, a population denoted as CD34+CD38-CD45RA-CD90±EPCR+ HSCs. This work aimed to evaluate the methodology for CD34+ HSC isolation, exploring differences in antibody clones, conjugates, source of cells and additional cell surface antigens (integrin-α6, CLEC9A and GPRC5C) to enhance the purity of these EPCR+ HSCs. We are emphasizing here the importance of experimental planning and antibody panel selection concerning the isolation of these human HSCs from multiple sources and providing important notes on the pitfalls of the reagents used for such purposes. Our results should enable a better reproducibility of results between labs, as well as further pursue work towards improving the enrichment of human HSCs.
    Keywords:  human hematopoietic stem cell markers; identification methods; methodology
    DOI:  https://doi.org/10.1016/j.exphem.2025.104729
  19. bioRxiv. 2025 Jan 24. pii: 2025.01.24.634694. [Epub ahead of print]
      Macrophages play central roles in immunity, wound healing, and homeostasis - a functional diversity that is underpinned by varying developmental origins. The impact of ontogeny on properties of human macrophages is inadequately understood. We demonstrate that definitive human fetal liver (HFL) hematopoietic stem cells (HSCs) possess two divergent paths of macrophage specification that lead to distinct identities. The monocyte-dependent pathway exists in both prenatal and postnatal hematopoiesis and generates macrophages with adult-like responses properties. We now uncover a fetal-specific pathway of expedited differentiation that generates tissue resident-like macrophages (TRMs) that retain HSC-like self-renewal programs governed by the aryl hydrocarbon receptor (AHR). We show that AHR antagonism promotes TRM expansion and mitigates inflammation in models of atopic dermatitis (AD). Overall, we directly connect path of differentiation with functional properties of macrophages and identify an approach to promote selective expansion of TRMs with direct relevance to inflammation and diseases of macrophage dysfunction.
    DOI:  https://doi.org/10.1101/2025.01.24.634694
  20. Biochem Biophys Rep. 2025 Mar;41 101894
      Acute myeloid leukaemia (AML) is a hard to treat blood cancer. Mutations in FLT3 are common among the genetic aberrations that characterise the cancer. Patients initially react to FLT3 inhibitors but drug resistance is a hinder to successful therapy. To better understand the mechanisms leading to drug resistance, we generated four AML cell lines resistant to the inhibitors gilteritinib or FF-10101, and explored their resistance mechanisms. We further tested whether the novel inhibitor Chen-9u could be used to limit cell growth. The results showed that each of the four resistant cell lines became resistant through a different mechanism. Resistant cells showed decreased FLT3 and increased NRAS pathway activity and reduced DNA synthesis due to decrease in CDK4 activity. Resistance mechanisms included resistance mutations in FLT3 (C695F and N701K), and a novel mutation in NRAS (G12C). In a fourth line, resistance might have developed through a MYCN mutation. Cell growth was inhibited by Chen-9u and resistant clones could not be obtained with this inhibitor. The results highlight opportunities and limitations. On the one hand, resistant cells were produced due to different mechanisms, showing the versatility of tumour cells. Furthermore, resistance developed to the most advanced inhibitors, one of which is covalent and the other non-covalent but highly specific. On the other hand, it is shown that DNA synthesis is reduced, which means that resistance has evolutionary consequences. Finally, the novel drug-resistant cell lines may serve as useful models for better understanding of the cellular events associated with inherent and acquired drug resistance.
    Keywords:  Acute myeloid leukemia; CDK4; DNA sequencing; Drug resistance; FF-10101; FLT3; Gilteritinib; NRAS
    DOI:  https://doi.org/10.1016/j.bbrep.2024.101894
  21. Lancet Haematol. 2025 Feb;pii: S2352-3026(24)00350-8. [Epub ahead of print]12(2): e128-e137
       BACKGROUND: In our previous study on erythropoiesis-stimulating agent (ESA) treatment in lower risk myelodysplastic syndromes from the European MDS (EUMDS) Registry, we showed that patients treated with ESAs had longer survival compared with patients who receive red blood cell transfusion (RBCT). In this study, with a longer follow up time and more patients included, we aimed to assess long-term effects on survival and health-related quality of life (HRQoL) of exposure to ESAs with or without RBCT in patients with lower risk myelodysplastic syndromes.
    METHODS: The EUMDS Registry is a non-interventional, longitudinal, real-world registry prospectively enrolling newly diagnosed patients older than 18 years with lower risk (International Prognostic Scoring System low or intermediate-1) myelodysplastic syndromes from 16 European countries and Israel. The analysis was restricted to patients with haemoglobin concentrations less than 100 g/L enrolled between Jan 1, 2008, and July 1, 2019, with last censoring of data on Dec 31, 2021. Patient management was recorded every 6 months, including treatment, transfusions, and HRQoL. ESA treatment followed local guidelines. The patients were separated into four groups at each study visit: no ESA or RBCT, ESA only, ESA plus RBCT, and RBCT only. The data were analysed longitudinally over time according to ESA and RBCT status during each 6-month interval, using propensity score matching. The main outcomes were median overall survival and leukaemia-free survival, and HRQoL. This study is registered with ClinicalTrials.gov, NCT00600860, as is ongoing.
    FINDINGS: 2448 patients (the ESA-unexposed group [n=1265] and ESA-exposed group [n=1183]) were diagnosed before July 1, 2019; 1520 (62·1%) were male and 928 (37·9%) were female. Median follow-up time was 3·9 years (IQR 1·6-6·5). After applying eligibility criteria and propensity matching, there were 426 patients in the ESA-unexposed group and 744 patients in the ESA-exposed group. Median overall survival in the ESA exposed group was 44·9 months (95% CI 40·2-50·5) compared with 34·8 months (28·6-39·2) in the ESA unexposed group; the absolute difference was 10·1 months (95% CI 2·2-18·0; hazard ratio [HR] 0·70 [95% CI 0·59-0·83]; p<0·0001). Patients without RBCT in the presence or absence of ESA exposure maintained significantly better HRQoL than those with RBCT, irrespective of ESA exposure (linear mixed effect model of EQ-5d-3L index score, RBCT coefficient -0·04 [95% CI -0·06 to 0·03], p<0·0001; linear mixed effect model of VAS, -4·57 [-6·02 to -3·13], p<0·0001).
    INTERPRETATION: ESA treatment in patients with lower risk myelodysplastic syndromes significantly improves overall survival when started before or early after the onset of regular transfusion therapy. Avoiding RBCT is associated with significantly better HRQoL.
    FUNDING: H2020 European Research Council, Novartis Pharmacy B V Oncology Europe, Amgen, BMS/Celgene International, Janssen Pharmaceutica, Takeda Pharmaceuticals International, and Gilead Sciences.
    DOI:  https://doi.org/10.1016/S2352-3026(24)00350-8
  22. Hematol Oncol. 2025 Mar;43(2): e70043
      This study, including 412 patients newly diagnosed with myelodysplastic neoplasm (MDS), investigated the clinical, molecular, and prognostic features of MDS with moderate-to-severe bone marrow fibrosis (MF). Among the patients with MDS, 347 (84%) had MF grade 0-1 (MF0-1), and 65 (16%) had MF grade 2-3 (MF2-3). Patients with MDS with MF2-3 showed similar overall survival (OS) (16.6 vs. 21.3 months; p = 0.34) but demonstrated inferior progression-free survival (PFS) (6.6 vs. 15.2 months; p = 0.02) and a higher risk of leukemia transformation (35.4 vs. 16.4%; p < 0.001) compared to those with MF0-1. In the MDS with excess blast (MDS-EB) subtypes, individuals with MF2-3 exhibited shorter OS (4.8 vs. 11.7 months; p = 0.01) and PFS (3.1 vs. 7.9 months; p = 0.006) than those in patients with MF0-1. However, individuals with MF0-1 and MF2-3 showed similar OS and PFS rates among the patients with the MDS non-excess blast (MDS-nonEB) subtypes. Additionally, we reclassified the patients with MDS according to the 2022 World Health Organization (WHO) classification. Patients with MDS with fibrosis (MDS-f) had a shorter OS (5.6 vs. 13.8 months; p = 0.01) and PFS (3.1 vs. 7.9 months; p = 0.006) than MDS with increased blasts (MDS-IB) subtypes. Our study reveals the unique features of patients with MDS-MF2-3 and validates the refinements made in the 5th edition of the WHO proposal.
    Keywords:  bone marrow fibrosis; gene mutation; myelodysplastic neoplasms; prognosis; world health organization classification
    DOI:  https://doi.org/10.1002/hon.70043
  23. Clin Lymphoma Myeloma Leuk. 2025 Jan 21. pii: S2152-2650(25)00015-1. [Epub ahead of print]
      Therapeutic strategies for chronic myeloid leukemia (CML) are rapidly evolving, with novel agents emerging to address the limitations of current treatments. Goals of CML management are disease control and achieve a deep and sustained molecular response for a possible successful treatment-free remission (TFR). However, a significant proportion of patients fail to reach adequate molecular response and require sequential therapies. A crucial aspect of treatment resistance lies in the persistence of leukemic stem cells (LSCs), which serve as a reservoir for disease recurrence. Increasing focus is placed on combination strategies to overcome the constraints of TKI monotherapy. Various strategies have been explored, starting with the combination of interferon (IFN) and TKIs. The investigation of alternative administration methods, dosing regimens, or extended treatment durations in clinical trials involving IFN represents potential avenues to address current conflicting results. Additionally, the combination of ATP-competitive TKIs with asciminib has shown encouraging preclinical and clinical results, with further data needed for a comprehensive safety profile. Recently, efforts to inhibit other signaling pathways have been explored but with contrasting results. Despite ongoing advancements, TKIs remain the cornerstone of both current and future combination therapies. Their integration with personalized approaches is crucial to overcome complex biological challenges and ensure long-term, effective and safe treatment for CML patients.
    Keywords:  Advancements; Combination; Leukemia stem cells; Treatment-free remission; Tyrosine kinase inhibitors
    DOI:  https://doi.org/10.1016/j.clml.2025.01.004
  24. Blood Adv. 2025 Feb 05. pii: bloodadvances.2024014879. [Epub ahead of print]
      High-dose post-transplantation cyclophosphamide (HD-PTCy), given at 50 mg/kg/day on days +3/+4, is a standard-of-care graft-versus-host disease (GVHD) prophylaxis for allogeneic hematopoietic cell transplantation (HCT). Our murine MHC-haploidentical HCT studies suggested intermediate-dose PTCy produces superior GVHD control compared with HD-PTCy and PTCy is maximally effective on day +4. We conducted a single-institutional prospective phase I/II trial (NCT03983850) to reduce PTCy dosing to 25 mg/kg/day on days +3/+4 or on day +4 only for myeloablative HLA-haploidentical bone marrow HCT using PTCy, sirolimus, and mycophenolate mofetil. Among 35 patients, 89% were ethnic/racial minorities, 46% had high/very-high-risk disease, and median comorbidity-score was 3. The phase I dose-limiting-toxicity, grade III-IV acute GVHD, was not observed after either reduced-PTCy dose-level. PTCy 25 mg/kg/day on days +3/+4 (intermediate-dose (ID)-PTCy; n=23), the phase II dose, resulted in no grade II-IV acute GVHD; 2-year cumulative incidences of chronic GVHD requiring systemic immunosuppression, non-relapse mortality, and relapse were 13%, 17%, and 22%, and 2-year overall survival, disease-free survival, and GVHD-free/relapse-free survival were 61%, 61%, and 52%. In exploratory analysis compared with HD-PTCy (n=5), ID-PTCy resulted in significantly faster engraftment and T-cell reconstitution, fewer transfusions, less mucositis, and reduced severity of BK-virus-associated cystitis; area-under-the-curve exposure of 4-hydroxycyclophosphamide (4HCY), a key cyclophosphamide metabolite, correlated with these outcomes but not with chronic GVHD occurrence. Ideal-body-weight-based PTCy dosing best approximated 4HCY exposure. Intermediate-dose PTCy is effective and has apparent clinical benefits compared with HD-PTCy. Before broader implementation, further studies are needed to confirm these findings and define optimal PTCy dosing across various donor/graft types. NCT03983850.
    DOI:  https://doi.org/10.1182/bloodadvances.2024014879
  25. Hemasphere. 2025 Feb;9(2): e70083
      As a consequence of rapidly developing genetic technologies and advances in the understanding of the pathogenesis of acute myeloid leukemia (AML), the classification of AML has moved gradually from a morphologic and cytochemical-based system to one that is genetically defined. Recent molecular and genetic developments have been integrated into the diagnostic criteria for AML in the fifth edition of the World Health Organization (WHO) Classification of Haematolymphoid Tumours and the 2022 International Consensus Classification (ICC) of Myeloid Neoplasms and Acute Leukemias, expanding the list of genetically defined entities. In this review article, we use a case-based format describing the diagnostic workup, risk stratification, and possible treatment options to highlight the impact of the 2022 WHO and ICC classifications on clinical practice. We show that despite much commentary and anguish, there is a significant overlap between the two classifications. We further highlight the fact that even for entities with divergent nomenclature, such as TP53-mutated AML, the actual genetic lesion leads to convergent therapy.
    DOI:  https://doi.org/10.1002/hem3.70083
  26. Ann Hematol. 2025 Feb 06.
      T-cell large granular lymphocytic leukemia (T-LGLL) is a rare hematologic neoplasm characterized by clonal expansion of CD3 + cytotoxic T lymphocytes and a highly heterogeneous clinical course. Conventional therapy primarily includes immunosuppressive regimen. However, optimal front-line approaches still need to be defined and refractory disease remains a clinical challenge. Thus, we here aimed to explore functional dependencies of T-LGLL as a basis for personalized therapeutic strategies. We performed functional apoptosis profiling and ex vivo drug treatment in a series of 8 clinically and genetically characterized T-LGLL patients from two German University hospitals. Our series of patients underscored the clinical and genetic heterogeneity of the disease. Genetically, only 2 patients harbored a STAT3 mutation. To identify targetable anti-apoptotic mechanisms, we performed selective functional BH3 profiling on the patients' CD8 + T-cells harboring the malignant T-LGLL cells versus the same patients' normal CD4 + T-cells. CD8 + cells in 50% of the patients (4/8) demonstrated a dominant functional dependence on MCL-1 as compared to the same patients' normal T-cells. Accordingly, CD8 + T-LGLL cells from patients with enhanced MCL1 dependence significantly responded to AZD-5991 ex vivo while no response was observed in the remaining samples lacking enhanced MCL-1 dependence. Across clinically and genetically heterogeneous cases of T-LGLL, functional apoptosis profiling identified patients with CD8 + T-LGLL cells harboring a dominant dependence on MCL-1 as a potential therapeutic target.
    Keywords:   STAT3 ; Apoptosis; BH3 profiling; MCL1; T-cell large granular lymphocytic leukemia (T-LGLL)
    DOI:  https://doi.org/10.1007/s00277-025-06230-3
  27. Nat Cell Biol. 2025 Jan 31.
      Haematopoietic stem cells (HSCs) self-renew and differentiate to replenish the pool of blood cells, which require a low but finely tuned protein synthesis rate. Nonetheless, the translatome landscape in HSCs and how the translation machinery orchestrates HSC self-renewal remain largely elusive. Here we perform ultra-low-input Ribo-seq in HSCs, progenitor and lineage cells, and reveal HSC-specific translated genes involved in rRNA processing. We systematically profile small nucleolar RNAs (snoRNAs) and uncover an indispensable role of the SNORD113-114 cluster in regulating HSC self-renewal. Maternal knockout (Mat-KO) of this cluster substantially impairs HSC self-renewal, whereas loss of the paternal allele shows no obvious phenotype. Mechanistically, Mat-KO results in dysregulation of translation machinery (rRNA 2'-O-Me modifications, pre-rRNA processing, 60S ribosome assembly and translation) and induces nucleolar stress in HSCs, which exempts p53 from Mdm2-mediated proteasomal degradation and leads to apoptosis. Collectively, our study provides a promising facet to our understanding of snoRNA-mediated regulation in HSC homeostasis.
    DOI:  https://doi.org/10.1038/s41556-024-01593-7
  28. bioRxiv. 2025 Jan 23. pii: 2025.01.21.634107. [Epub ahead of print]
      Understanding the pathways regulating normal and malignant hematopoietic stem cell (HSC) biology is important for improving outcomes for patients with hematologic disorders. Epithelial Growth Factor Like-7 (EGFL7 ) is ∼30 kDa secreted protein that is highly expressed in adult HSCs. Using Egfl7 genetic knock-out ( Egfl7 KO) mice and recombinant EGFL7 (rEGFL7) protein, we examined the role of Egfl7 in regulating normal hematopoiesis. We found that Egfl7 KO mice had decreases in overall BM cellularity resulting in significant reduction in the number of hematopoietic stem and progenitor cells (HSPCs), which was due to dysregulation of normal cell-cycle progression along with a corresponding increase in quiescence. rEGFL7 treatment rescued our observed hematopoietic defects of Egfl7 KO mice and enhanced HSC expansion after genotoxic stress such as 5-FU and irradiation. Furthermore, treatment of WT mice with recombinant EGFL7 (rEGFL7) protein expands functional HSCs evidenced by an increase in transplantation potential. Overall, our data demonstrates a role for EGFL7 in HSC expansion and survival and represents a potential strategy for improving transplant engraftment or recovering bone marrow function after stress.
    DOI:  https://doi.org/10.1101/2025.01.21.634107
  29. Ann Hematol. 2025 Feb 05.
      The colony-stimulating factor 3 receptor (CSF3R) plays an essential role in differentiation, growth, and survival of granulocytes. Driver mutations in CSF3R gene represent a diagnostic marker of chronic neutrophilic leukemia (CNL). Less commonly, these mutations are observed in other myeloid neoplasms but their pathogenetic and prognostic role is still unclear. Here, we analyzed a large cohort of myeloid neoplasms to evaluate the incidence of CSF3R mutations and co-mutational profile. Mutational analysis was performed using targeted NGS myeloid panel in a consecutive cohort of 360 patients with myeloid neoplasms. Mutations in CSF3R were identified in 20/360 (5.6%) cases. A CSF3R gene mutation was present in 13/179 AML cases (7.3%), in 2/27 (7.4%) CMML cases, in 1/94 (1.1%) MDS cases and in 4/60 (6.7%) other myeloid neoplasms. The frequencies of patients with CSF3R mutations lowered to 2.8% in all cases and 3.4% in AML, excluding cases with variants of uncertain significance (VUS). A total of 23 mutations of CSF3R gene were detected, half localized in the extracellular domain, 5 in the transmembrane region (type I) and 6 mutations in the cytoplasmic domain (type II). In AML, CSF3R mutations were more frequent in patients harboring CBF alterations (25.0%) and CEBPA mutations (11.8%). Two cases with AML harboring pathogenic CSF3R variants were primary refractory to induction therapy. CMML cases with T618I variant showed a myeloproliferative phenotype. Overall, our findings support the notion that CSF3R variants, particularly type I and II pathogenic mutations, may modulate the phenotypic features of leukemic cells in myeloid neoplasia.
    Keywords:  CSF3R; Co-mutational pattern; Disease outcome; Myeloid neoplasia
    DOI:  https://doi.org/10.1007/s00277-025-06232-1
  30. Exp Hematol. 2025 Feb 01. pii: S0301-472X(25)00021-9. [Epub ahead of print] 104730
      The transcription factor Krüppel-like factor 4 (KLF4) acts as a transcriptional activator and repressor. KLF4 plays a role in various cellular processes, including the dedifferentiation of somatic cells into induced pluripotent stem cells. Although it has been shown to enhance self-renewal in embryonic and leukemia stem cells, its role in adult hematopoietic stem cells (HSC) remains underexplored. We demonstrate that conditional deletion of the Klf4 gene in hematopoietic cells led to an increased frequency of immunophenotypic hematopoietic stem cells (HSCs) in the bone marrow, along with a normal distribution of lymphoid and myeloid progenitor cells. Non-competitive bone marrow transplants showed normal engraftment and multi-lineage reconstitution, except for monocytes and T cells. However, the loss of KLF4 hindered hematological reconstitution in competitive serial bone marrow transplants, highlighting a critical role for KLF4 in stress-induced hematopoiesis. Transcriptome analysis revealed an upregulation of NFκB2 and toll-like receptors (e.g., TLR4) in Klf4-null HSCs during homeostasis. Flow cytometry and immunoblot analysis confirmed the increased cell surface expression of TLR4 and the activation of NFκB2 in HSCs under homeostatic conditions, whereas NFκB2 expression drops after radiation compared to steady-state levels. Our findings suggest that the constitutive activation of the TLR4-NFκB2 pathway inhibits the ability of HSCs to regenerate blood after transplantation in cytoablated bone marrow.
    Keywords:  KLF4; bone marrow; hematopoietic stem cells; self-renewal
    DOI:  https://doi.org/10.1016/j.exphem.2025.104730
  31. Cell. 2025 Jan 10. pii: S0092-8674(24)01420-X. [Epub ahead of print]
      Ubiquinone (UQ), the only known electron carrier in the mammalian electron transport chain (ETC), preferentially delivers electrons to the terminal electron acceptor oxygen (O2). In hypoxia, ubiquinol (UQH2) diverts these electrons onto fumarate instead. Here, we identify rhodoquinone (RQ), an electron carrier detected in mitochondria purified from certain mouse and human tissues that preferentially delivers electrons to fumarate through the reversal of succinate dehydrogenase, independent of environmental O2 levels. The RQ/fumarate ETC is strictly present in vivo and is undetectable in cultured mammalian cells. Using genetic and pharmacologic tools that reprogram the ETC from the UQ/O2 to the RQ/fumarate pathway, we establish that these distinct ETCs support unique programs of mitochondrial function and that RQ confers protection upon hypoxia exposure in vitro and in vivo. Thus, in discovering the presence of RQ in mammals, we unveil a tractable therapeutic strategy that exploits flexibility in the ETC to ameliorate hypoxia-related conditions.
    Keywords:  electron transport chain; hypoxia; ischemia; metabolism; mitochondria; rhodoquinone
    DOI:  https://doi.org/10.1016/j.cell.2024.12.007
  32. Leukemia. 2025 Feb 02.
      Recent pan-cancer analysis revealed the global pattern and potential aetiologies of copy number variation signatures in human cancers, particularly those derived from non-hematopoietic tissues. In sharp contrast, the generally low CNV burden in leukemia leaves the CNV landscape and variations largely unexplored, impeding understanding of CNV in leukemia development. Through a comprehensive compilation of public datasets, we constructed LeukAtlas ( https://ngdc.cncb.ac.cn/leukemia ), a user-friendly database encompassing 12,597 CNVs from 1446 AML samples across diverse subtypes and age groups, providing tools for multidimensional CNV analysis. Our analyses suggested the CNV levels significantly varied among AML patients. We discovered two previously unknown CNV patterns in adult AML patients, dominated by segmental LOH and/or minor gain, which have been shown to be associated with chromosomal instability in solid tumors. Additionally, we defined two potential new AML subgroups based on CNVs status, providing new stratification markers within the existing karyotype framework. Representing the most extensive CNV collection in AML, LeukAtlas is a valuable resource for exploring the role of CNVs in the pathogenesis and prognosis stratification of leukemia. Interrogation of this database uncovers novel subclasses with unique CNV profiles and reveals heterogeneous CNV patterns in AML, demonstrating the potential role of chromosomal instability in AML progression.
    DOI:  https://doi.org/10.1038/s41375-025-02514-9
  33. Blood. 2025 Feb 03. pii: blood.2024025036. [Epub ahead of print]
      Chronic graft-versus-host disease (cGVHD) is the leading cause of morbidity and non-relapse associated mortality following allogeneic hematopoietic cell transplantation (aHSCT). Treating steroid resistant/refractory cGVHD remains challenging. Epigenetic regulators can have global transcriptional effects that control donor T-cell responses. We previously showed that inhibiting histone lysine motifs by chromatin-modifying enzymes can ameliorate murine cGVHD. Targeting donor T-cell DNA methyltransferases reduce acute GVHD. Here, we sought to investigate the DNA demethylase Tet (ten-eleven translocase) methylcytosine dioxygenases 2 (Tet2) and Tet3 in T follicular helper cell (TFH) dependent cGVHD. In a clinically relevant model of cGVHD that recapitulates pulmonary fibrosis from bronchiolitis obliterans, recipients of Tet2 deleted donor T-cells did not have improved pulmonary function tests in contrast to the markedly improved pulmonary function in Tet3 deleted donor T-cells. Tet3 deleted donor T-cells did not impair TFH-dependent germinal center (GC) formation. Unexpectedly, TET3 deficiency resulted in elevated GATA3 expression in and IL-4 production by TFH cells. TET3 deficient TFH cells supported GC B-cell immunoglobulin (Ig) class switching to nonpathogenic IgG1 but not pathogenic IgG2c allowing mice to escape cGVHD pulmonary fibrosis. Elevated GATA3 expression and disruption of IgG2c class switching was recapitulated in an in-vitro human GC culture system. These studies provide new insights into the function of Tet3 in TFH driven Ig class switching and suggest a new approach to mitigate cGVHD.
    DOI:  https://doi.org/10.1182/blood.2024025036