bims-tremyl Biomed News
on Therapy resistance biology in myeloid leukemia
Issue of 2023‒07‒30
forty-six papers selected by
Paolo Gallipoli
Barts Cancer Institute, Queen Mary University of London
  1. Combined GLUT1 and OXPHOS inhibition eliminates acute myeloid leukemia cells by restraining their metabolic plasticity.
  2. Prevalence and significance of DDX41 gene variants in the general population.
  3. Interplay of TP53 allelic state, blast count and complex karyotype on survival of patients with AML and MDS.
  4. Prediction of risk for myeloid malignancy in clonal hematopoiesis.
  5. Venetoclax-based therapy for relapsed or refractory acute myeloid leukaemia following intensive induction chemotherapy.
  6. Arginine dependency is a therapeutically exploitable vulnerability in chronic myeloid leukaemic stem cells.
  7. DNAJC10 maintains survival and self-renewal of leukemia stem cells through PERK branch of the unfolded protein response.
  8. Building on Foundations: Venetoclax-Based Combinations in the Treatment of Acute Myeloid Leukemia.
  9. Oncostatin M is a Master Regulator of an Inflammatory Network in Dnmt3a -Mutant Hematopoietic Stem Cells.
  10. Hematopoietic Stem Cell (HSC)-Independent Progenitors Are Susceptible to Mll-Af9-Induced Leukemic Transformation.
  11. Cigarette smoke exposure accelerates AML progression in FLT3-ITD models.
  12. Genetic, Phenotypic, and Clinical Heterogeneity of NPM1-Mutant Acute Myeloid Leukemias.
  13. Perturbed epigenetic transcriptional regulation in AML with IDH mutations causes increased susceptibility to NK cells.
  14. Advances in acute myeloid leukemia differentiation therapy: A critical review.
  15. Ciclopirox Ethanolamine Preserves the Immature State of Human HSCs by Mediating Intracellular Iron Content.
  16. Genetic modification of inflammation and clonal hematopoiesis-associated cardiovascular risk.
  17. Cohesin complex mutations in myeloid neoplasms are enriched for SRSF2, RUNX1, TET2, and NRAS co-mutations and morphologic dysplasia.
  18. Performance of IPSS-M in patients with myelodysplastic syndrome after hypomethylating agent failure.
  19. Prognostic Value of Pretreatment Fetal Hemoglobin Levels in Patients with Myelodysplastic Syndromes and Acute Myeloid Leukemia Treated with Azacitidine: A Single-center Retrospective Study.
  20. Functional characterization and response to FLT3 inhibitors in acute myeloid leukaemia with a non-canonical FLT3 mutation: A proof of concept.
  21. Characteristics and outcomes of patients with chronic myeloid leukemia and T315I mutation treated in the pre- and post-ponatinib era.
  22. Subclones with variants of uncertain clinical significance might contribute to ineffective hemopoiesis and leukemia predisposition.
  23. Myeloproliferative Neoplasm Driven by ETV6-ABL1 in an Adolescent with Recent History of Burkitt Leukemia.
  24. Novel covalent CDK7 inhibitor potently induces apoptosis in acute myeloid leukemia and synergizes with Venetoclax.
  25. Genetic and chemical targeting of the ATPase complex TIP48 and 49 impairs acute myeloid leukemia.
  26. PU.1 is required to restrain myelopoiesis during chronic inflammatory stress.
  27. Gene regulatory network analysis predicts cooperating transcription factor regulons required for FLT3-ITD+ AML growth.
  28. Integrated genomic and transcriptomic analysis improves disease classification and risk stratification of MDS with ring sideroblasts.
  29. The Absolute Monocyte Count at Diagnosis Affects Prognosis in Myelodysplastic Syndromes Independently of the IPSS-R Risk Score.
  30. The graft-versus-leukemia effect of prophylactic donor lymphocyte infusions after allogeneic stem cell transplantation is equally effective in relapse prevention but safer compared to spontaneous graft-versus-host disease.
  31. Unlocking the Role of Endothelial MPL Receptor and JAK2V617F Mutation: Insights into Cardiovascular Dysfunction in MPNs and CHIP.
  32. The (near) miracle of therapy in chronic myeloid leukaemia.
  33. PARP10 is highly expressed and associated with inferior outcomes in acute myeloid leukemia.
  34. Survival expectation after thrombosis and overt-myelofibrosis in essential thrombocythemia and prefibrotic myelofibrosis: a multistate model approach.
  35. Clinical Flow Cytometry Analysis in the Setting of Chronic Myeloid Neoplasms and Clonal Hematopoiesis.
  36. Investigation of the impact of clonal hematopoiesis on severity and pathophysiology of COVID-19 in rhesus macaques.
  37. Loss of Nudt15 thiopurine detoxification increases direct DNA damage in hematopoietic stem cells.
  38. WT1 and PRAME RNA-loaded dendritic cell vaccine as maintenance therapy in de novo AML after intensive induction chemotherapy.
  39. ZDHHC21: a mitochondrial vulnerability in AML.
  40. Clonal Hematopoiesis of Indeterminate Potential From a Heart Failure Specialist's Point of View.
  41. Ten years of treatment with ruxolitinib for myelofibrosis: a review of safety.
  42. Immune modulation in chronic myeloid leukaemia patients treated with nilotinib and interferon-alpha.
  43. Next-Generation JAK2 Inhibitors for the Treatment of Myeloproliferative Neoplasms: Lessons from Structure-Based Drug Discovery Approaches.
  44. One disease, two faces: clonally-related AML and MPDCP with skin involvement.
  45. The JAK1/2 inhibitor ruxolitinib in patients with COVID-19 triggered hyperinflammation: the RuxCoFlam trial.
  46. Parallel CRISPR-Cas9 screens identify mechanisms of PLIN2 and lipid droplet regulation.
  1. Blood Adv. 2023 Jul 28. pii: bloodadvances.2023009967. [Epub ahead of print]
    Combined GLUT1 and OXPHOS inhibition eliminates acute myeloid leukemia cells by restraining their metabolic plasticity.
    Maria Rodriguez-Zabala, Ramprasad Ramakrishnan, Katrin Reinbach, Somadri Ghosh, Leal Oburoglu, Antoni Falqués-Costa, Kishan Bellamkonda, Mats Ehinger, Pablo Peña-Martínez, Noelia Puente-Moncada, Henrik Lilljebjörn, Jörg Cammenga, Cornelis Jan Pronk, Vladimir Lazarevic, Thoas Fioretos, Anna Hagström-Andersson, Niels-Bjarne Woods, Marcus Järås.
      Acute myeloid leukemia (AML) is initiated and propagated by leukemia stem cells (LSCs), a self-renewing population of leukemia cells responsible for therapy resistance. Hence, there is an urgent need to identify new therapeutic opportunities targeting LSCs. Here we performed an in vivo CRISPR knockout screen to identify potential therapeutic targets by interrogating cell surface dependencies of LSCs. The facilitated glucose transporter type 1 (GLUT1) emerged as a critical in vivo metabolic dependency for LSCs in a murine MLL::AF9-driven model of AML. GLUT1 disruption by genetic ablation or pharmacological inhibition led to suppression of leukemia progression and improved survival of mice transplanted with LSCs. Metabolic profiling revealed that Glut1 inhibition suppressed glycolysis, decreased levels of tricarboxylic acid (TCA) cycle intermediates, and increased the levels of amino acids. This metabolic reprogramming was accompanied by an increase in autophagic activity and apoptosis. Moreover, Glut1 disruption caused transcriptional, morphological and immunophenotypic changes consistent with differentiation of AML cells. Notably, dual inhibition of GLUT1 and oxidative phosphorylation (OXPHOS) exhibited synergistic anti-leukemic effects in the majority of primary AML patient samples tested by restraining their metabolic plasticity. In particular, RUNX1-mutated primary leukemia cells displayed striking sensitivity to the combination treatment compared to normal CD34+ bone marrow and cord blood cells. Collectively, our study reveals a GLUT1 dependency of murine LSCs in the bone marrow microenvironment, and demonstrates that dual inhibition of GLUT1 and OXPHOS is a promising therapeutic approach for AML.
    DOI:  https://doi.org/10.1182/bloodadvances.2023009967
  2. Blood. 2023 Jul 28. pii: blood.2023020209. [Epub ahead of print]
    Prevalence and significance of DDX41 gene variants in the general population.
    Sruthi Cheloor Kovilakam, Muxin Gu, William G Dunn, Ludovica Marando, Clea Barcena, Serena Nik-Zainal, Irina Mohorianu, Siddhartha Kar, Margarete Alice Fabre, Pedro M Quiros, George S Vassiliou.
      Germline variants in the DDX41 gene have been linked to myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) development. However, the risks associated with different variants remain unknown, as do the basis of their leukemogenic properties, impact on steady-state hematopoiesis and links to other cancers. Here, we investigate the frequency and significance of DDX41 variants in 454,792 United Kingdom Biobank (UKB) participants and identify 452 unique non-synonymous DNA variants in 3,538 (1/129) individuals. Many were novel and prevalence of most varied markedly by ancestry. Amongst the 1059 individuals with germline pathogenic variants (DDX41-GPV) 34 developed MDS/AML (odds ratio 12.3 versus non-carriers). Of these 7/218 had start-loss, 22/584 truncating and 5/257 missense (odds ratios: 12.9, 15.1 and 7.5 respectively). Using multivariate regression, we found significant associations of DDX41-GPV with MDS, AML and "family history of leukemia", but not lymphoma, myeloproliferative neoplasms or other cancers. We also report that DDX41-GPV carriers do not have an increased prevalence of clonal hematopoiesis (CH). In fact, CH was significantly more common prior to sporadic versus DDX41-mutant MDS/AML, revealing distinct evolutionary paths. Furthermore, somatic mutation rates did not differ between sporadic and DDX41-mutant AML genomes, ruling out genomic instability as a driver of the latter. Finally, we found that higher mean red cell volume and somatic DDX41 mutations in blood DNA identify DDX41-GPV carriers at increased MDS/AML risk. Collectively, our findings give new insights into the prevalence and cognate risks associated with DDX41 variants, as well as the clonal evolution and early detection of DDX41-mutant MDS/AML.
    DOI:  https://doi.org/10.1182/blood.2023020209
  3. Blood Adv. 2023 Jul 28. pii: bloodadvances.2023010312. [Epub ahead of print]
    Interplay of TP53 allelic state, blast count and complex karyotype on survival of patients with AML and MDS.
    Anna Stengel, Manja Meggendorfer, Wencke Walter, Constance Baer, Niroshan Nadarajah, Stephan Hutter, Wolfgang Kern, Torsten Haferlach, Claudia Haferlach.
      Several clinical and genetic factors impact on overall survival (OS) in myelodysplastic neoplasms (MDS) and acute myeloid leukemia (AML), including complex karyotype (CK), TP53 allelic state and blast count. We analysed the interplay of these factors by performing Cox regression analysis and by determining the frequency of TP53 single hit (sh) and double hit (dh) events and OS in MDS (n=747) with <5% blasts, ≥5%,<10% blasts, ≥10%,<20% blasts and in AML (n=772). MDS<5% blasts showed the best outcome, followed by MDS≥5%,<10% blasts, MDS≥10%,<20% blasts and AML (median OS, 75, 54, 27, 18 months, respectively). The same hierarchy was observed when each subgroup was divided into TP53sh, TP53dh and without TP53 alterations (alt), revealing a dismal outcome of TP53dh in all subgroups (17, 10, 8, 1 month). MDS<5% blasts differed from the other subgroups by showing predominantly TP53sh (76% of TP53alt cases), and by an independent adverse impact of CK on OS (HR=5.2, p<0.001). The remaining subgroups displayed many similarities, as TP53dh was found at high frequencies (67%, 91%, 71%, respectively) and only TP53alt but not CK independently influenced OS, TP53dh showing the strongest influence. When the total cohort was split according to TP53 state, only the blast count and not CK had an independent adverse impact on OS in all subgroups. Thus, TP53dh is the strongest prognostic factor, further supporting its integration into risk stratification guidelines and classification as separate entity. However, also the blast count influences OS independent of TP53 state, whereas CK plays a minor prognostic role.
    DOI:  https://doi.org/10.1182/bloodadvances.2023010312
  4. NEJM Evid. 2023 May;2(5):
    Prediction of risk for myeloid malignancy in clonal hematopoiesis.
    Lachelle D Weeks, Abhishek Niroula, Donna Neuberg, Waihay Wong, R Coleman Lindsley, Marlise Luskin, Nancy Berliner, Richard M Stone, Daniel J DeAngelo, Robert Soiffer, Md Mesbah Uddin, Gabriel Griffin, Caitlyn Vlasschaert, Christopher J Gibson, Siddhartha Jaiswal, Alexander G Bick, Luca Malcovati, Pradeep Natarajan, Benjamin L Ebert.
      Background: Clonal hematopoiesis of indeterminate potential (CHIP) and clonal cytopenia of undetermined significance (CCUS) are defined by somatic mutations in genes associated with myeloid neoplasms (MN) at a variant allele fraction (VAF) ≥ 0.02, in the absence and presence of cytopenia, respectively. CHIP/CCUS is highly prevalent in adults and defining predictors of MN risk would aid clinical management and research.Methods: We analyzed sequenced exomes of healthy UK Biobank (UKB) participants (n = 438,890) in separate derivation and validation cohorts. Genetic mutations, laboratory values, and MN outcomes were used in conditional probability-based recursive partitioning and Cox regression to determine predictors of incident MN. Combined statistical weights defined a clonal hematopoiesis risk score (CHRS). Independent CHIP/CCUS patient cohorts were used to test prognostic capability of the CHRS in the clinical setting.
    Results: Recursive partitioning distinguished CHIP/CCUS cases with 10-year probabilities of MN ranging from 0.0078 - 0.85. Multivariable analysis validated partitioning variables as predictors of MN. Key features, including single DNMT3A mutations, high risk mutations, ≥ 2 mutations, VAF ≥ 0.2, age ≥ 65 years, CCUS vs CHIP and red blood cell indices, influenced MN risk in variable direction. The CHRS defined low risk (n = 10018, 88.4%), intermediate risk (n = 1196, 10.5%), and high risk (n = 123, 1.1%) groups. In clinical cohorts, most MN events occurred in high risk CHIP/CCUS patients.
    Conclusions: The CHRS provides simple prognostic framework for CHIP/CCUS, distinguishing a high risk minority from the majority of CHIP/CCUS which has minimal risk for progression to MN.
    DOI:  https://doi.org/10.1056/evidoa2200310
  5. Eur J Haematol. 2023 Jul 25.
    Venetoclax-based therapy for relapsed or refractory acute myeloid leukaemia following intensive induction chemotherapy.
    Daniel Tuyet Kristensen, Rasmus Froberg Brøndum, Andreas Due Ørskov, Claus Werenberg Marcher, Claudia Schöllkopf, Anne Louise Tølbøll Sørensen, Marianne Tang Severinsen, Martin Bøgsted, Anne Stidsholt Roug.
      BACKGROUND: The treatment of relapsed or refractory (R/R) acute myeloid leukaemia (AML) remains challenging and outcomes extremely poor. The introduction of venetoclax has transformed the treatment of AML and emerging data suggest that venetoclax-based therapy may enforce salvage treatment.MATERIALS AND METHODS: In this nationwide Danish retrospective study, we analysed treatment outcomes of venetoclax-based salvage treatment for R/R AML between 2019 and 2022. Only venetoclax-naive patients who had previously received treatment with intensive chemotherapy therapy were included.
    RESULTS: The cohort consisted of 43 R/R patients with a median age of 57 years. Nine (20.9%) were primary refractory and 34 (79.1%) patients had relapsed, including 21 after previous allogeneic stem cell transplantation. The overall response rate was 76.2% including 61.9% with composite complete remission (CRc: CR + CRi). Among CRc-responders with information on measurable residual disease (MRD), 8/13 (61.5%) obtained an MRD-negativity response. The overall survival was 9.3 months for all patients with an estimated 1-year overall survival of 34%. For CRc-responders the median overall survival was 13.3 months, and the median relapse-free survival was 12.8 months.
    CONCLUSION: Venetoclax-based salvage treatment for R/R AML produced high response rates; however, for most patients the response was of limited duration. This study is limited by an observational design and prone to selection bias.
    Keywords:  BCL-2; acute myeloid leukaemia; measurable residual disease; relapse/refractory; venetoclax
    DOI:  https://doi.org/10.1111/ejh.14046
  6. EMBO Rep. 2023 Jul 25. e56279
    Arginine dependency is a therapeutically exploitable vulnerability in chronic myeloid leukaemic stem cells.
    Kevin M Rattigan, Martha M Zarou, Zuzana Brabcova, Bodhayan Prasad, Désirée Zerbst, Daniele Sarnello, Eric R Kalkman, Angela Ianniciello, Mary T Scott, Karen Dunn, Engy Shokry, David Sumpton, Mhairi Copland, Saverio Tardito, Johan Vande Voorde, Francis Mussai, Paul Cheng, G Vignir Helgason.
      To fuel accelerated proliferation, leukaemic cells undergo metabolic deregulation, which can result in specific nutrient dependencies. Here, we perform an amino acid drop-out screen and apply pre-clinical models of chronic phase chronic myeloid leukaemia (CML) to identify arginine as a nutrient essential for primary human CML cells. Analysis of the Microarray Innovations in Leukaemia (MILE) dataset uncovers reduced ASS1 levels in CML compared to most other leukaemia types. Stable isotope tracing reveals repressed activity of all urea cycle enzymes in patient-derived CML CD34+ cells, rendering them arginine auxotrophic. Thus, arginine deprivation completely blocks proliferation of CML CD34+ cells and induces significantly higher levels of apoptosis when compared to arginine-deprived cell lines. Similarly, primary CML cells, but not normal CD34+ samples, are particularly sensitive to treatment with the arginine-depleting enzyme, BCT-100, which induces apoptosis and reduces clonogenicity. Moreover, BCT-100 is highly efficacious in a patient-derived xenograft model, causing > 90% reduction in the number of human leukaemic stem cells (LSCs). These findings indicate arginine depletion to be a promising and novel strategy to eradicate therapy resistant LSCs.
    Keywords:  amino acids; leukaemic stem cells; metabolism; therapy resistance
    DOI:  https://doi.org/10.15252/embr.202256279
  7. Haematologica. 2023 Jul 27.
    DNAJC10 maintains survival and self-renewal of leukemia stem cells through PERK branch of the unfolded protein response.
    Minjing Li, Xingli Wu, Meiyang Chen, Shiyu Hao, Yue Yu, Xiang Li, Erdi Zhao, Ming Xu, Zhenhai Yu, Zhiqiang Wang, Ning Xu, Changzhu Jin, Yancun Yin.
      Leukemia stem cells (LSCs) requires frequent adaptation to maintenance self-renewal ability despite they are longer exposure to cell-intrinsic and cell-extrinsic stresses. However, the mechanism by which LSCs maintain their leukemogenic activities and how individual LSCs respond to stress remain poorly understood. Herein, we found that DNAJC10, a member of HSP40 family, was frequently upregulated in various types of acute myeloid leukemia (AML) and in LSC-enriched cells. Deficiency of DNAJC10 leads to a dramatic increase in the apoptosis of both human leukemia cell lines and LSCs enriched populations. Although DNAJC10 is not required for normal hematopoiesis, deficiency of Dnajc10 significantly abrogated AML development and suppressed self-renewal of LSCs in the MLL-AF9-induced murine leukemia model. Mechanistically, inhibition of DNAJC10 specifically induces endoplasmic reticulum (ER) stress and promotes activating of PERK-EIF2α-ATF4 branch of unfolded protein response (UPR). Blocking PERK by GSK2606414 (PERKi) or shRNA rescued the loss of function of DNAJC10 both in vitro and in vivo. Importantly, deficiency of DNAJC10 increased sensitivity of AML cells to daunorubicin (DNR) and cytarabine (Ara-C). These data revealed that DNAJC10 functions as an oncogene in MLL-AF9-induced AML via regulating PERK branch of the UPR. DNAJC10 may be an ideal therapeutic target for eliminating LSCs and improving the effectiveness of DNR and Ara-C.
    DOI:  https://doi.org/10.3324/haematol.2023.282691
  8. Cancers (Basel). 2023 Jul 12. pii: 3589. [Epub ahead of print]15(14):
    Building on Foundations: Venetoclax-Based Combinations in the Treatment of Acute Myeloid Leukemia.
    Emmanuella Oyogoa, Elie Traer, Jeffrey Tyner, Curtis Lachowiez.
      Frontline acute myeloid leukemia (AML) treatment is determined by a combination of patient and genetic factors. This includes patient fitness (i.e., comorbidities that increase the risk of treatment-related mortality) and genetic characteristics, including cytogenetic events and gene mutations. In older unfit patients, the standard of care treatment is typically venetoclax (VEN) combined with hypomethylating agents (HMA). Recently, several drugs have been developed targeting specific genomic subgroups of AML patients, enabling individualized therapy. This has resulted in investigations of doublet and triplet combinations incorporating VEN aimed at overcoming known resistance mechanisms and improving outcomes in older patients with AML. These combinations include isocitrate dehydrogenase-1/2 (IDH1/2) inhibitors (i.e., ivosidenib and enasidenib), fms-like tyrosine kinase 3 (FLT3) inhibitors (i.e., gilteritinib), anti-CD47 antibodies (i.e., magrolimab), mouse double minute-2 (MDM2) inhibitors, and p53 reactivators (i.e., eprenetapopt). This review summarizes ongoing trials aimed at overcoming known VEN resistance mechanisms and improving outcomes beyond that observed with HMA + VEN combinations in the treatment of AML.
    Keywords:  acute myeloid leukemia; combined targeted therapy; hypomethylating agent; venetoclax
    DOI:  https://doi.org/10.3390/cancers15143589
  9. bioRxiv. 2023 Jul 12. pii: 2023.07.12.548764. [Epub ahead of print]
    Oncostatin M is a Master Regulator of an Inflammatory Network in Dnmt3a -Mutant Hematopoietic Stem Cells.
    Logan S Schwartz, Kira A Young, Timothy M Stearns, Nathan Boyer, Kristina D Mujica, Jennifer J Trowbridge.
      Age-associated clonal hematopoiesis (CH) occurs due to somatic mutations accrued in hematopoietic stem cells (HSCs) that confer a selective advantage in the context of aging. The mechanisms by which CH-mutant HSCs gain this advantage with aging are not comprehensively understood. Using unbiased transcriptomic approaches, we identify Oncostatin M (OSM) signaling as a candidate contributor to aging-driven Dnmt3a -mutant CH. We find that Dnmt3a -mutant HSCs from young mice do not functionally respond to acute OSM stimulation with respect to proliferation, apoptosis, hematopoietic engraftment, or myeloid differentiation. However, young Dnmt3a -mutant HSCs transcriptionally upregulate an inflammatory cytokine network in response to acute OSM stimulation including genes encoding IL-6, IL-1β and TNFα. In addition, OSM-stimulated Dnmt3a -mutant HSCs upregulate the anti-inflammatory genes Socs3, Atf3 and Nr4a1 , creating a negative feedback loop limiting sustained activation of the inflammatory network. In the context of an aged bone marrow (BM) microenvironment with chronically elevated levels of OSM, Dnmt3a -mutant HSCs upregulate pro-inflammatory genes but do not upregulate Socs3, Atf3 and Nr4a1 . Together, our work suggests that chronic inflammation with aging exhausts the regulatory mechanisms in young CH-mutant HSCs that resolve inflammatory states, and that OSM is a master regulator of an inflammatory network that contributes to age-associated CH.
    DOI:  https://doi.org/10.1101/2023.07.12.548764
  10. Cancers (Basel). 2023 Jul 14. pii: 3624. [Epub ahead of print]15(14):
    Hematopoietic Stem Cell (HSC)-Independent Progenitors Are Susceptible to Mll-Af9-Induced Leukemic Transformation.
    Cristiana Barone, Roberto Orsenigo, Anna Cazzola, Elisabetta D'Errico, Arianna Patelli, Giulia Quattrini, Barbara Vergani, Silvia Bombelli, Sofia De Marco, Cristina D'Orlando, Cristina Bianchi, Biagio Eugenio Leone, Raffaella Meneveri, Andrea Biondi, Giovanni Cazzaniga, Terence Howard Rabbitts, Silvia Brunelli, Emanuele Azzoni.
      Infant acute myeloid leukemia (AML) is a heterogeneous disease, genetically distinct from its adult counterpart. Chromosomal translocations involving the KMT2A gene (MLL) are especially common in affected infants of less than 1 year of age, and are associated with a dismal prognosis. While these rearrangements are likely to arise in utero, the cell of origin has not been conclusively identified. This knowledge could lead to a better understanding of the biology of the disease and support the identification of new therapeutic vulnerabilities. Over the last few years, important progress in understanding the dynamics of fetal hematopoiesis has been made. Several reports have highlighted how hematopoietic stem cells (HSC) provide little contribution to fetal hematopoiesis, which is instead largely sustained by HSC-independent progenitors. Here, we used conditional Cre-Lox transgenic mouse models to engineer the Mll-Af9 translocation in defined subsets of embryonic hematopoietic progenitors. We show that embryonic hematopoiesis is generally permissive for Mll-Af9-induced leukemic transformation. Surprisingly, the selective introduction of Mll-Af9 in HSC-independent progenitors generated a transplantable myeloid leukemia, whereas it did not when introduced in embryonic HSC-derived cells. Ex vivo engineering of the Mll-Af9 rearrangement in HSC-independent progenitors using a CRISPR/Cas9-based approach resulted in the activation of an aberrant myeloid-biased self-renewal program. Overall, our results demonstrate that HSC-independent hematopoietic progenitors represent a permissive environment for Mll-Af9-induced leukemic transformation, and can likely act as cells of origin of infant AML.
    Keywords:  CRISPR/Cas9; Mll-Af9; cell of origin; erythro-myeloid progenitors; hematopoiesis; hematopoietic stem cell; infant AML
    DOI:  https://doi.org/10.3390/cancers15143624
  11. Blood Adv. 2023 Jul 24. pii: bloodadvances.2023010111. [Epub ahead of print]
    Cigarette smoke exposure accelerates AML progression in FLT3-ITD models.
    Mary Figueroa, Huaxian Ma, Mansour Alfayez, Daniel Enrique Morales-Mantilla, Fei Wang, Yue Lu, Marcos Estecio, Katherine Y King, Eugenie S Kleinerman, Seyed Javad Moghaddam, Naval G Daver, Michael Andreeff, Marina Y Konopleva, Courtney D DiNardo, Joya Chandra.
      
    DOI:  https://doi.org/10.1182/bloodadvances.2023010111
  12. Biomedicines. 2023 Jun 24. pii: 1805. [Epub ahead of print]11(7):
    Genetic, Phenotypic, and Clinical Heterogeneity of NPM1-Mutant Acute Myeloid Leukemias.
    Ugo Testa, Elvira Pelosi, Germana Castelli.
      The current classification of acute myeloid leukemia (AML) relies largely on genomic alterations. AML with mutated nucleophosmin 1 (NPM1-mut) is the largest of the genetically defined groups, involving about 30% of adult AMLs and is currently recognized as a distinct entity in the actual AML classifications. NPM1-mut AML usually occurs in de novo AML and is associated predominantly with a normal karyotype and relatively favorable prognosis. However, NPM1-mut AMLs are genetically, transcriptionally, and phenotypically heterogeneous. Furthermore, NPM1-mut is a clinically heterogenous group. Recent studies have in part clarified the consistent heterogeneities of these AMLs and have strongly supported the need for an additional stratification aiming to improve the therapeutic response of the different subgroups of NPM1-mut AML patients.
    Keywords:  acute myeloid leukemia; clonal evolution; genetic classification; mutational profiling; prognostic stratification; transcriptome analysis
    DOI:  https://doi.org/10.3390/biomedicines11071805
  13. Leukemia. 2023 Jul 26.
    Perturbed epigenetic transcriptional regulation in AML with IDH mutations causes increased susceptibility to NK cells.
    Anna Palau, Filip Segerberg, Michael Lidschreiber, Katja Lidschreiber, Aonghus J Naughton, Maria Needhamsen, Lisa Anna Jung, Maja Jagodic, Patrick Cramer, Sören Lehmann, Mattias Carlsten, Andreas Lennartsson.
      Isocitrate dehydrogenase (IDH) mutations are found in 20% of acute myeloid leukemia (AML) patients. However, only 30-40% of the patients respond to IDH inhibitors (IDHi). We aimed to identify a molecular vulnerability to tailor novel therapies for AML patients with IDH mutations. We characterized the transcriptional and epigenetic landscape with the IDH2i AG-221, using an IDH2 mutated AML cell line model and AML patient cohorts, and discovered a perturbed transcriptional regulatory network involving myeloid transcription factors that were partly restored after AG-221 treatment. In addition, hypermethylation of the HLA cluster caused a down-regulation of HLA class I genes, triggering an enhanced natural killer (NK) cell activation and an increased susceptibility to NK cell-mediated responses. Finally, analyses of DNA methylation data from IDHi-treated patients showed that non-responders still harbored hypermethylation in HLA class I genes. In conclusion, this study provides new insights suggesting that IDH mutated AML is particularly sensitive to NK cell-based personalized immunotherapy.
    DOI:  https://doi.org/10.1038/s41375-023-01972-3
  14. Biochem Pharmacol. 2023 Jul 26. pii: S0006-2952(23)00300-3. [Epub ahead of print] 115709
    Advances in acute myeloid leukemia differentiation therapy: A critical review.
    Amal Kamal Abdel-Aziz.
      Acute myeloid leukemia (AML) is characterized by impaired differentiation and indefinite proliferation of abnormal myeloid progenitors. Although differentiating agents were deemed to revolutionize AML therapy, most treated non-APL AML patients are refractory or relapse. According to cancer stem cell model, leukemia-initiating cells are the root cause of relapse given their unidirectional potential to generate differentiated AML blasts. Nonetheless, accumulating evidences emphasize the de-differentiation plasticity and leukemogenic potential of mature AML blasts and the frailty of targeting leukemic stem cells per se. This review critically discusses the potential and challenges of (lessons learnt from) conventional and novel differentiating agents in AML therapy. Although differentiating agents might hold promise, they should be exploited within the context of a rationale combination regimen eradicating all maturation/differentiation states of AML cells. The results of the routinely used immunophenotypic markers and/or morphological analyses of differentiation should be carefully interpreted given their propensity to underestimate AML burden.
    Keywords:  AML; Dedifferentiation; LSC; Relapse; Remission; Resistance
    DOI:  https://doi.org/10.1016/j.bcp.2023.115709
  15. Blood Adv. 2023 Jul 24. pii: bloodadvances.2023009844. [Epub ahead of print]
    Ciclopirox Ethanolamine Preserves the Immature State of Human HSCs by Mediating Intracellular Iron Content.
    Mehrnaz Safaee Talkhoncheh, Aurélie Baudet, Fredrik Ek, Agatheeswaran Subramaniam, Yun-Ruei Kao, Natsumi Miharada, Christine Karlsson, Leal Oburoglu, Anna Rydström, Kristijonas Žemaitis, Abdul Ghani Alattar, Justyna Rak, Kristian Pietras, Roger Olsson, Britta Will, Jonas Larsson.
      Culture conditions in which hematopoietic stem cells (HSCs) can be expanded for clinical benefit are highly sought after. To elucidate regulatory mechanisms governing the maintenance and propagation of human HSCs ex vivo, we screened libraries of annotated small molecules in human cord blood (CB) cells using an optimized assay for detection of functional HSCs during culture. We found that the antifungal agent ciclopirox ethanolamine (CPX) selectively supported immature CD34+CD90+ cells during culture and enhanced their long-term in vivo repopulation capacity. Purified HSCs treated with CPX showed a reduced cell division rate and an enrichment of HSC- specific gene expression patterns. Mechanistically, we found that the HSC stimulating effect of CPX was directly mediated by chelation of the intracellular iron pool, which in turn affected iron-dependent proteins and enzymes mediating cellular metabolism and respiration. Our findings unveil a significant impact of iron homeostasis in regulation of human HSCs, with important implications for both basic HSC biology and clinical hematology.
    DOI:  https://doi.org/10.1182/bloodadvances.2023009844
  16. J Clin Invest. 2023 Jul 27. pii: e168597. [Epub ahead of print]
    Genetic modification of inflammation and clonal hematopoiesis-associated cardiovascular risk.
    Zhi Yu, Trevor P Filder, Yunfeng Ruan, Caitlyn Vlasschaert, Tetsushi Nakao, Md Mesbah Uddin, Taralynn Mack, Abhishek Niroula, J Brett Heimlich, Seyedeh M Zekavat, Christopher J Gibson, Gabriel K Griffin, Yuxuan Wang, Gina M Peloso, Nancy Heard-Costa, Daniel Levy, Ramachandran S Vasan, François Aguet, Kristin G Ardlie, Kent D Taylor, Stephen S Rich, Jerome I Rotter, Peter Libby, Siddhartha Jaiswal, Benjamin L Ebert, Alexander G Bick, Alan R Tall, Pradeep Natarajan.
      Clonal hematopoiesis of indeterminate potential (CHIP) is associated with an increased risk of cardiovascular diseases (CVD), putatively via inflammasome activation. We pursued an inflammatory gene modifier scan for CHIP-associated CVD risk among 424,651 UK Biobank participants. CHIP was identified using whole exome sequencing data of blood DNA and modeled both as a composite and for common drivers (DNMT3A, TET2, ASXL1, and JAK2) separately. We developed predicted gene expression scores for 26 inflammasome-related genes and assessed how they modify CHIP-associated CVD risk. We identify IL1RAP as a potential key molecule for CHIP-associated CVD risk across genes and increased AIM2 gene expression leading to heightened JAK2- and ASXL1-associated CVD risks. We show that CRISPR-induced Asxl1 mutated murine macrophages have a particularly heightened inflammatory response to AIM2 agonism, associated with an increased DNA damage response, as well as increased IL-10 secretion, mirroring a CVD protective effect of IL10 expression in ASXL1 CHIP. Our study supports the role of inflammasomes in CHIP-associated CVD and provides new evidence to support gene-specific strategies to address CHIP-associated CVD risk.
    Keywords:  Cardiology; Cardiovascular disease; Genetics; Mouse models; Population genetics
    DOI:  https://doi.org/10.1172/JCI168597
  17. Leuk Res. 2023 Jul 20. pii: S0145-2126(23)00622-7. [Epub ahead of print]132 107357
    Cohesin complex mutations in myeloid neoplasms are enriched for SRSF2, RUNX1, TET2, and NRAS co-mutations and morphologic dysplasia.
    Christian K Hirt, Nandan Padmanabha, Phillip D Michaels.
      
    Keywords:  Acute myeloid leukemia; Cohesin; Myelodysplastic syndrome; Phylogeny; STAG2
    DOI:  https://doi.org/10.1016/j.leukres.2023.107357
  18. Am J Hematol. 2023 Jul 29.
    Performance of IPSS-M in patients with myelodysplastic syndrome after hypomethylating agent failure.
    Samuel Urrutia, Kelly S Chien, Ziyi Li, Alex Bataller, Emmanuel Almanza, Koji Sasaki, Guillermo Montalban-Bravo, Nicholas J Short, Elias Jabbour, Tapan M Kadia, Farhad Ravandi, Gautam Borthakur, Yesid Alvarado, Naval Daver, Rashmi Kanagal-Shamanna, Carlos Bueso-Ramos, Sherry A Pierce, Hagop Kantarjian, Guillermo Garcia-Manero.
      Evaluation of IPSS-M and exploratory prognostic model for MDS at the time of HMA failure.
    DOI:  https://doi.org/10.1002/ajh.27043
  19. Intern Med. 2023 Jul 26.
    Prognostic Value of Pretreatment Fetal Hemoglobin Levels in Patients with Myelodysplastic Syndromes and Acute Myeloid Leukemia Treated with Azacitidine: A Single-center Retrospective Study.
    Tomoyuki Saga, Michiyo Kanagawa, Tomoya Harada, Lang Lang, Fumihiko Yamawaki, Toshimichi Ishihara.
      Objective Azacitidine (AZA) has been the standard of care for elderly patients with high-risk myelodysplastic syndromes (MDS). However, reliable clinical predictors of outcome have yet to be identified. The prognostic value of fetal hemoglobin (HbF) levels has been reported for decitabine therapy. We evaluated pretreatment HbF levels in AZA monotherapy as a prognostic marker in MDS/acute myeloid leukemia (AML). Methods This study included chemotherapy-naïve patients who had received seven-day treatment schedules of AZA and whose HbF levels were measured at the onset of treatment between March 2011 and July 2020. Patients were grouped into HbF-normal (<1.0%) or HbF-elevated (≥1.0%) groups. Responses were classified according to the International Working Group 2006 criteria. Patients Twenty-nine patients were included and classified as having either MDS (n=21), chronic myelomonocytic leukemia (n=5), myelodysplastic/myeloproliferative neoplasm unclassifiable (n=1), or AML with <30% marrow blasts (n=2) based on the World Health Organization 2016 diagnostic criteria. According to the revised International Prognostic Scoring System classification, 20/29 patients were at intermediate, high, or very high risk. Pretreatment HbF levels were elevated in 13/29 patients. Results The median follow-up duration was 13.0 (range 1.5-93.5) months. The HbF-elevated group was associated with a significantly higher hematologic improvement rate (76.9% vs. 25%, p=0.009) and better overall survival (median, 21.0 vs. 13.0 months,p=0.048) than the HbF-normal group. Conclusion These results suggest that elevated pretreatment HbF levels can predict better outcomes in patients with MDS/AML treated with AZA.
    Keywords:  azacitidine; epigenetics; fetal hemoglobin; myelodysplastic syndromes
    DOI:  https://doi.org/10.2169/internalmedicine.1216-22
  20. Br J Haematol. 2023 Jul 23.
    Functional characterization and response to FLT3 inhibitors in acute myeloid leukaemia with a non-canonical FLT3 mutation: A proof of concept.
    Serena Travaglini, Carmelo Gurnari, Silvia Antonelli, Francesco Marchesi, Gioia De Angelis, Tiziana Ottone, Mariadomenica Divona, Antonio Cristiano, Hajro Hajrullaj, Andrea Mengarelli, Maria Teresa Voso.
      
    DOI:  https://doi.org/10.1111/bjh.18991
  21. Am J Hematol. 2023 Jul 23.
    Characteristics and outcomes of patients with chronic myeloid leukemia and T315I mutation treated in the pre- and post-ponatinib era.
    Fadi G Haddad, Koji Sasaki, Aram Bidikian, Ghayas C Issa, Tapan Kadia, Nitin Jain, Yesid Alvarado, Nicholas J Short, Naveen Pemmaraju, Sanam Loghavi, Keyur P Patel, Rashmi Kanagal-Shamanna, Musa Yilmaz, Lucia Masarova, Elias Jabbour, Hagop Kantarjian.
      Patients with chronic myeloid leukemia (CML) and T315I mutation generally have a poor prognosis. Their outcome in the post-ponatinib era remains unclear. We reviewed patients with CML in chronic (CP) or accelerated phase (AP) who developed a T315I mutation between March 15, 2004, and July 26, 2022. Patients were divided into CP, AP, or blastic phase (BP) at the time of mutation detection. Overall survival (OS) was defined from the time of mutation detection to the date of death or last follow-up. We identified a total of 107 patients: 54 (51%) in CP, 14 (13%) in AP, and 39 (36%) in BP. One hundred and two patients received subsequent therapy after the T315I mutation was detected. At a median follow-up of 75 months (95% CI, 41-110), the median OS was 49 months (95% CI, 26-73) and the 5-year OS rate was 44%. Patients who were in CML-CP at the time of mutation detection had better survival compared with those in AP or BP, with a median OS of 132, 31, and 6 months, and 5-year OS rates of 70%, 37%, and 10%, respectively (p < .001). Patients with CML-CP treated with ponatinib and/or asciminib had a 5-year OS of 77% compared with 50% in those who received other treatments (chemotherapy, second-generation tyrosine kinase inhibitors, homoharringtonine, and investigational drugs) (p = .14). In summary, patients with CML-CP at the time of T315I mutation detection may have a relatively indolent disease course with a long-term OS of 70%. Treatment with third-generation tyrosine kinase inhibitors seemed to improve survival in patients with CML-CP.
    DOI:  https://doi.org/10.1002/ajh.27037
  22. Eur J Haematol. 2023 Jul 27.
    Subclones with variants of uncertain clinical significance might contribute to ineffective hemopoiesis and leukemia predisposition.
    Valentina Giudice, Bianca Serio, Santa Errichiello, Idalucia Ferrara, Alessandra Galdiero, Angela Bertolini, Roberta Visconti, Danilo De Novellis, Roberto Guariglia, Serena Luponio, Denise Morini, Anna Maria Della Corte, Anna Maria Sessa, Francesco Verdesca, Maddalena Langella, Barbara Izzo, Carmine Selleri.
      BACKGROUND: Splicing modifications, genomic instability, and hypomethylation are central mechanisms promoting myelodysplasia and acute myeloid leukemia (AML). In this real-life retrospective study, to elucidate pathophysiology of clonal hemopoiesis in hematological malignancies, we investigated clinical significance of mutations in leukemia-related genes of known pathogenetic significance and of variants of uncertain clinical significance (VUS) in a cohort of patients with MDS and AML.METHODS: A total of 59 consecutive subjects diagnosed with MDS, 48 with AML, and 17 with clonal cytopenia with unknown significance were screened for somatic mutations in AML-related genes by next-generation sequencing.
    RESULTS: We showed that TET2, SETBP1, ASXL1, EZH2, RUNX1, SRSF2, DNMT3A, and IDH1/2 were commonly mutated. MDS patients also showed a high genetic complexity, especially for SETBP1. Moreover, the presence of SETBP1 wild-type or two or more simultaneous VUS variants identified a subgroup of AML and MDS patients with better outcome, while the presence of single SETBP1 VUS variant was related to a worse prognosis, regardless TET2 mutational status.
    CONCLUSIONS: In conclusions, we linked both pathogenic and VUS variants in AML-related genes to clonal hematopoiesis; therefore, we proposed to consider those variants as prognostic markers in leukemia and myelodysplasia. However, further studies in larger prospective cohorts are required to validate our results.
    Keywords:  acute myeloid leukemia; clonal hematopoiesis; myelodysplastic syndromes; pathogenic mutations; variants of uncertain significance
    DOI:  https://doi.org/10.1111/ejh.14069
  23. Curr Oncol. 2023 Jun 21. 30(7): 5946-5952
    Myeloproliferative Neoplasm Driven by ETV6-ABL1 in an Adolescent with Recent History of Burkitt Leukemia.
    Samuele Renzi, Fatimah Algawahmed, Scott Davidson, Karin P S Langenberg, Fabio Fuligni, Salah Ali, Nathaniel Anderson, Ledia Brunga, Jack Bartram, Mohamed Abdelhaleem, Ahmed Naqvi, Kassa Beimnet, Andre Schuh, Anne Tierens, David Malkin, Adam Shlien, Mary Shago, Anita Villani.
      ETV6-ABL1 gene fusion is a rare genetic rearrangement in a variety of malignancies, including myeloproliferative neoplasms (MPN), acute lymphoblastic leukemia (ALL), and acute myeloid leukemia (AML). Here, we report the case of a 16-year-old male diagnosed with a MPN, 7 months post-completion of treatment for Burkitt leukaemia. RNA sequencing analysis confirmed the presence of an ETV6-ABL1 fusion transcript, with an intact, in-frame ABL tyrosine-kinase domain. Of note, secondary ETV6-ABL1-rearranged neoplastic diseases have not been reported to date. The patient was started on a tyrosine kinase inhibitor (TKI; imatinib) and, subsequently, underwent a 10/10 matched unrelated haematopoietic stem cell transplant. He is disease-free five years post-transplant. Definitive evidence of the prognostic influence of the ETV6-ABL1 fusion in haematological neoplasms is lacking; however, overall data suggest that it is a poor prognostic factor, particularly in patients with ALL and AML. The presence of this ETV6-ABL1 fusion should be more routinely investigated, especially in patients with a CML-like picture. More routine use of whole-genome and RNA sequencing analyses in clinical diagnostic care, in conjunction with conventional cytogenetics, will facilitate these investigations.
    Keywords:  myeloproliferative syndrome; oncology; pediatric malignancies
    DOI:  https://doi.org/10.3390/curroncol30070444
  24. J Exp Clin Cancer Res. 2023 Jul 29. 42(1): 186
    Novel covalent CDK7 inhibitor potently induces apoptosis in acute myeloid leukemia and synergizes with Venetoclax.
    Tarang Gaur, Ramulu Poddutoori, Leena Khare, Bhausaheb Bagal, Sonal Rashmi, Nikhil Patkar, Prashant Tembhare, Subramanian Pg, Dhanlaxmi Shetty, Amit Dutt, Qi Zhang, Marina Konopleva, Uwe Platzbeckar, Sudeep Gupta, Susanta Samajdar, Murali Ramchandra, Navin Khattry, Syed K Hasan.
      INTRODUCTION: The emergence of resistance to the highly successful BCL2-directed therapy is a major unmet need in acute myeloid leukemia (AML), an aggressive malignancy with poor survival rates. Towards identifying therapeutic options for AML patients who progress on BCL2-directed therapy, we studied a clinical-stage CDK7 inhibitor XL102, which is being evaluated in solid tumors (NCT04726332).MATERIALS AND METHODS: To determine the anti-proliferative effects of XL102, we performed experiments including time-resolved fluorescence resonance energy transfer, target occupancy, cell cycle and apoptosis-based assays. We also included genetically characterized primary myeloid blasts from de novo and relapsed/refractory AML patients. For mechanistic studies, CRISPR/Cas9 mediated knockout of CDK7 and c-Myc and immunoblotting were performed. NOD/SCID orthotropic and subcutaneous AML xenografts were used to determine anti-leukemic effects. To assess the synergistic effects of XL102 with Venetoclax, we performed RNA sequencing and gene set enrichment analysis using Venetoclax sensitive and resistant model systems.
    RESULTS: XL102, a highly specific, orally bioavailable covalent inhibitor of CDK7. Inhibitory effect on CDK7 by XL102 in primary myeloid blasts (n = 54) was in nanomolar range (mean = 300 nM; range = 4.0-952 nM). XL102 treated AML cells showed a reduction in phosphorylation levels of Serine 2/5/7 at carboxy-terminal domain of RNA polymerase II. T-loop phosphorylation of CDK1(Thr161) and CDK2(Thr160) was inhibited by XL102 in dose-dependent manner leading to cell-cycle arrest. c-Myc downregulation and enhanced levels of p53 and p21 in XL102 treated cells were observed. Increased levels of p21 and activation of p53 by XL102 were mimicked by genetic ablation of CDK7, which supports that the observed effects of XL102 are due to CDK7 inhibition. XL102 treated AML xenografts showed remarkable reduction in hCD45 + marrow cells (mean = 0.60%; range = 0.04%-3.53%) compared to vehicle control (mean = 38.2%; range = 10.1%-78%), with corresponding increase in p53, p21 and decrease in c-Myc levels. The data suggests XL102 induces apoptosis in AML cells via CDK7/c-Myc/p53 axis. RNA-sequencing from paired Venetoclax-sensitive and Venetoclax-resistant cells treated with XL102 showed downregulation of genes involved in proliferation and apoptosis.
    CONCLUSION: Taken together, XL102 with Venetoclax led to synergistic effects in overcoming resistance and provided a strong rationale for clinical evaluation of XL102 as a single agent and in combination with Venetoclax.
    Keywords:  Acute myeloid leukemia; Apoptosis; CDK7 inhibition; CRISPR/Cas9; Cell cycle; Venetoclax resistance; Xenografts
    DOI:  https://doi.org/10.1186/s13046-023-02750-w
  25. Leukemia. 2023 Jul 25.
    Genetic and chemical targeting of the ATPase complex TIP48 and 49 impairs acute myeloid leukemia.
    Ayuna Hattori, Emi Takamatsu-Ichihara, Yoshiki Yamamoto, Shuhei Fujita, Kazutsune Yamagata, Takuo Katsumoto, Yukino Machida, Haruka Shinohara, Ryo Murakami, Issay Kitabayashi.
      The chromatin-associated AAA+ ATPases Tip48 and Tip49 are the core components of various complexes implicated in diverse nuclear events such as DNA repair and gene regulation. Although they are frequently overexpressed in many human cancers, their functional significance remains unclear. Here, we show that loss of Tip49 triggered p53-dependent apoptosis and inhibited leukemia development in vivo. To examine the impact of chemical inhibition of this complex on leukemia, we have developed the novel compound DS-4950, which interferes with the ATPase activity of the Tip48/49. Administration of DS-4950 was well-tolerated in healthy mice, and the drug effectively reduced tumor burden and improved survival. We also provide evidence that the dependency on Tip48/49 is widely conserved in non-hematologic malignancies with wild type p53. These results demonstrated that the Tip48/49 ATPases are functionally necessary and therapeutically targetable for the treatment of human cancers.
    DOI:  https://doi.org/10.1038/s41375-023-01971-4
  26. Front Cell Dev Biol. 2023 ;11 1204160
    PU.1 is required to restrain myelopoiesis during chronic inflammatory stress.
    James S Chavez, Jennifer L Rabe, Katia E Niño, Harrison H Wells, Rachel L Gessner, Taylor S Mills, Giovanny Hernandez, Eric M Pietras.
      Chronic inflammation is a common feature of aging and numerous diseases such as diabetes, obesity, and autoimmune syndromes and has been linked to the development of hematological malignancy. Blood-forming hematopoietic stem cells (HSC) can contribute to these diseases via the production of tissue-damaging myeloid cells and/or the acquisition of mutations in epigenetic and transcriptional regulators that initiate evolution toward leukemogenesis. We previously showed that the myeloid "master regulator" transcription factor PU.1 is robustly induced in HSC by pro-inflammatory cytokines such as interleukin (IL)-1β and limits their proliferative activity. Here, we used a PU.1-deficient mouse model to investigate the broader role of PU.1 in regulating hematopoietic activity in response to chronic inflammatory challenges. We found that PU.1 is critical in restraining inflammatory myelopoiesis via suppression of cell cycle and self-renewal gene programs in myeloid-biased multipotent progenitor (MPP) cells. Our data show that while PU.1 functions as a key driver of myeloid differentiation, it plays an equally critical role in tailoring hematopoietic responses to inflammatory stimuli while limiting expansion and self-renewal gene expression in MPPs. These data identify PU.1 as a key regulator of "emergency" myelopoiesis relevant to inflammatory disease and leukemogenesis.
    Keywords:  PU.1; hematopoiesis; hematopoietic progenitor cell; hematopoietic stem cell; inflammation; myelopoiesis
    DOI:  https://doi.org/10.3389/fcell.2023.1204160
  27. bioRxiv. 2023 Jul 19. pii: 2023.07.18.549495. [Epub ahead of print]
    Gene regulatory network analysis predicts cooperating transcription factor regulons required for FLT3-ITD+ AML growth.
    Daniel J L Coleman, Peter Keane, Rosario Luque-Martin, Paulynn S Chin, Helen Blair, Luke Ames, Sophie G Kellaway, James Griffin, Elizabeth Holmes, Sandeep Potluri, Salam A Assi, John Bushweller, Olaf Heidenreich, Peter N Cockerill, Constanze Bonifer.
      AML is a heterogenous disease caused by different mutations. We have previously shown that each mutational sub-type develops its specific gene regulatory network (GRN) with transcription factors interacting with multiple gene modules, many of which are transcription factor genes themselves. Here we hypothesized that highly connected nodes within such networks comprise crucial regulators of AML maintenance. We tested this hypothesis using FLT3-ITD mutated AML as a model and conducted an shRNA drop-out screen informed by this analysis. We show that AML-specific GRNs predict identifying crucial regulatory modules required for AML but not normal cellular growth. Furthermore, our work shows that all modules are highly connected and regulate each other. The careful multi-omic analysis of the role of one (RUNX1) module by shRNA and chemical inhibition shows that this transcription factor and its target genes stabilize the GRN of FLT3-ITD AML and that its removal leads to GRN collapse and cell death.
    DOI:  https://doi.org/10.1101/2023.07.18.549495
  28. Clin Cancer Res. 2023 Jul 27. pii: CCR-23-0538. [Epub ahead of print]
    Integrated genomic and transcriptomic analysis improves disease classification and risk stratification of MDS with ring sideroblasts.
    Gabriele Todisco, Maria Creignou, Elsa Bernard, Ann-Charlotte Björklund, Pedro Luis Moura, Bianca Tesi, Teresa Mortera Blanco, Birgitta Sander, Monika Jansson, Gunilla Walldin, Indira Barbosa, Susanne E Reinsbach, Isabel Juliana Hofman, Christer Nilsson, Tetsuichi Yoshizato, Marios Dimitriou, David Chang, Svanhildur Olafsdottir, Sigita Venckute Larsson, Magnus Tobiasson, Luca Malcovati, Petter Woll, Sten-Eirik W Jacobsen, Elli Papaemmanuil, Eva Hellström-Lindberg.
      PURPOSE: Ring sideroblasts (RS) define the low-risk myelodysplastic neoplasm (MDS) subgroup with RS but may also reflect erythroid dysplasia in higher-risk myeloid neoplasm. The benign behavior of MDS with RS (MDSRS+) is limited to SF3B1-mutated cases without additional high-risk genetic events, but one third of MDSRS+ carry no SF3B1 mutation, suggesting that different molecular mechanisms may underlie RS formation. We integrated genomic and transcriptomic analyses to evaluate whether transcriptome profiles may improve current risk stratification.EXPERIMENTAL DESIGN: We studied a prospective cohort of MDSRS+ patients irrespective of WHO class with regard to somatic mutations, copy number alterations and bone marrow CD34+ cell transcriptomes to assess whether transcriptome profiles add to prognostication and provide input on disease classification.
    RESULTS: SF3B1, SRSF2 or TP53 multi-hit (MH) mutations were found in 89% of MDSRS+ cases, and each mutation category was associated with distinct clinical outcome, gene expression, and alternative splicing profiles. Unsupervised clustering analysis identified three clusters with distinct hemopoietic stem and progenitor (HSPC) composition, which only partially overlapped with mutation groups. IPSS-M and the transcriptome-defined proportion of megakaryocyte/erythroid progenitors (MEP) independently predicted survival in multivariable analysis.
    CONCLUSION: These results provide essential input on the molecular basis of SF3B1-unmutated MDSRS+ and propose HSPC quantification as a prognostic marker in myeloid neoplasms with RS.
    DOI:  https://doi.org/10.1158/1078-0432.CCR-23-0538
  29. Cancers (Basel). 2023 Jul 11. pii: 3572. [Epub ahead of print]15(14):
    The Absolute Monocyte Count at Diagnosis Affects Prognosis in Myelodysplastic Syndromes Independently of the IPSS-R Risk Score.
    Tobias Silzle, Sabine Blum, Annika Kasprzak, Kathrin Nachtkamp, Martina Rudelius, Barbara Hildebrandt, Katharina S Götze, Norbert Gattermann, Michael Lauseker, Ulrich Germing.
      The absolute monocyte count (AMC) is associated with mortality in a variety of medical conditions. Its prognostic impact in myelodysplastic syndromes (MDSs) is less well studied. Therefore, we investigated its potential prognostic value in a cohort from the Düsseldorf MDS registry in relationship to the revised international prognostic scoring system (IPSS-R). An AMC below the population's median (<0.2 × 109/L) was associated with several adverse disease features such as lower haemoglobin levels, lower count of neutrophils and platelets, and a higher percentage of blasts in the bone marrow. MDS patients with an AMC < 0.2 × 109/L had a significantly higher risk of progression into acute myeloid leukemia (AML). In a univariate, proportional hazards model the effect of the AMC as a continuous variable was modelled via p-splines. We found a U-shaped effect with the lowest hazard around 0.3 × 109/L. Accordingly, an AMC within the last quartile of the population (0.4 × 109/L) was associated with a reduced overall survival independently of IPSS-R, but not with the risk of secondary AML. Considering monocytopenia as a risk factor for AML progression in MDS may provide an additional argument for allogeneic transplantation or the use of hypomethylating agents in patients who are not clear candidates for those treatments according to current prognostic scoring systems and/or recommendations. Further studies are needed to assess the prognostic impact of the AMC in the context of prognostic scoring systems, considering the molecular risk profile, and to identify the mechanisms responsible for the higher mortality in MDS patients with a subtle monocytosis.
    Keywords:  absolute monocyte count; myelodysplastic syndrome; prognostication; revised international prognostic scoring system
    DOI:  https://doi.org/10.3390/cancers15143572
  30. Ann Hematol. 2023 Jul 25.
    The graft-versus-leukemia effect of prophylactic donor lymphocyte infusions after allogeneic stem cell transplantation is equally effective in relapse prevention but safer compared to spontaneous graft-versus-host disease.
    Michael Stadler, Lothar Hambach, Elke Dammann, Helmut Diedrich, Haytham Kamal, Iyas Hamwi, Christian Schultze-Florey, Michael Varvenne, Steve Ehrlich, Stefanie Buchholz, Christian Koenecke, Gernot Beutel, Eva M Weissinger, Jürgen Krauter, Matthias Eder, Bernd Hertenstein, Arnold Ganser.
      Therapeutic donor lymphocyte infusions (tDLI) are used to reinforce the graft-versus-leukemia (GvL) effect in relapse after allogeneic stem cell transplantation (alloSCT). In contrast, the role of prophylactic DLI (proDLI) in preventing leukemia relapse has been less clearly established, although supported by retrospective, case-control, and registry analyses. We report a prospective, monocentric, ten year cohort of patients with high risk acute leukemias (AL) or myelodysplasia (MDS) in whom proDLI were applied beyond day +120 post alloSCT to compensate for lack of GvL.272 consecutive allotransplanted AL or MDS patients in complete remission and off immunosuppression at day +120 were stratified according to the prior appearance of relevant GvHD (acute GvHD °II-IV or extensive chronic GvHD) as a clinical indicator for GvL. Escalating doses of unmodified proDLI were applied to 72/272 patients without prior relevant GvHD. Conversely, 157/272 patients with prior spontaneous GvHD did not receive proDLI, nor did 43/272 patients with contraindications (uncontrolled infections, patient refusal, DLI unavailability).By day 160-landmark analysis (median day of first DLI application), proDLI recipients had significantly higher five-year overall (OS) and disease free survival (DFS) (77% and 67%) than patients with spontaneous GvHD (54% and 53%) or with contraindications (46% and 45%) (p=0.003). Relapse incidence for patients with proDLI (30%) or spontaneous GvHD (29%) was significantly lower than in patients with contraindications (39%; p=0.021). With similar GvHD incidence beyond day +160, non-relapse mortality (NRM) was less with proDLI (5%) than without proDLI (18%; p=0.036).In conclusion, proDLI may be able to compensate for lack of GvL in alloSCT recipients with high risk AL or MDS.
    Keywords:  Acute leukemia; Allogeneic stem cell transplantation; Graft-versus-host; Graft-versus-leukemia; Myelodysplastic syndrome; Prophylactic donor lymphocyte infusion
    DOI:  https://doi.org/10.1007/s00277-023-05276-5
  31. bioRxiv. 2023 Jul 13. pii: 2023.07.12.548716. [Epub ahead of print]
    Unlocking the Role of Endothelial MPL Receptor and JAK2V617F Mutation: Insights into Cardiovascular Dysfunction in MPNs and CHIP.
    Haotian Zhang, Nicholas Kafeiti, Sandy Lee, Kyla Masarik, Haoyi Zheng, Huichun Zhan.
      Patients with JAK2V617F-positive myeloproliferative neoplasms (MPNs) and clonal hematopoiesis of indeterminate potential (CHIP) are at a significantly higher risk of cardiovascular diseases (CVDs). Endothelial cells (ECs) carrying the JAK2V617F mutation can be detected in many MPN patients. Here, we investigated the impact of endothelial JAK2V617F mutation on CVD development using both transgenic murine models and human induced pluripotent stem cell lines. Our findings revealed that JAK2V617F mutant ECs promote CVDs by impairing endothelial function and undergoing endothelial-to-mesenchymal transition (EndMT). Importantly, we found that inhibiting the endothelial thrombopoietin receptor MPL suppressed JAK2V617F-induced EndMT and prevented cardiovascular dysfunction caused by mutant ECs. These findings propose that targeting the endothelial MPL receptor could be a promising therapeutic approach to manage CVD complications in patients with JAK2V617F-positive MPNs and CHIP. Further investigations into the impact of other CHIP-associated mutations on endothelial dysfunction are needed to improve risk stratification for individuals with CHIP.
    DOI:  https://doi.org/10.1101/2023.07.12.548716
  32. Br J Haematol. 2023 Jul 26.
    The (near) miracle of therapy in chronic myeloid leukaemia.
    Jerald P Radich.
      
    Keywords:  chronic myeloid leukaemia; dasatinib; treatment-free remission
    DOI:  https://doi.org/10.1111/bjh.18956
  33. Aging (Albany NY). 2023 Jul 27. 15
    PARP10 is highly expressed and associated with inferior outcomes in acute myeloid leukemia.
    Ling Wang, Chuang Jiang, Dandan Hu.
      Acute myeloid leukemia is a heterogeneous disease of the hematopoietic system, which possesses a poor prognosis; thus, the identification of novel molecular markers is urgently needed to better define the risk stratification and optimize treatment therapies for this disease. Here, we investigated the roles of the PARP family genes in AML by analyzing their mRNA expression profiles and their association with clinical features using data from TCGA and GSE. Our results showed that PARP10 was significantly more highly expressed in AML samples than in normal controls, and high expression of PARP10 was associated with older age (≥60 years, P = 0.012), more frequent TP53 mutations (P = 0.024), high-risk stratification (P < 0.05), and poorer outcomes (P < 0.05). Patients with high expression of PARP10 exhibited significantly poorer overall survival (OS) and event-free survival (EFS) than those with low PARP10 expressions (OS: median: 0.88 vs. 2.19 years; P = 0.001; EFS: median: 0.65 vs. 1.12 years; P = 0.041). Multivariate analysis indicated that high expression of PARP10 was an independent risk factor for poorer OS and EFS in AML patients. Moreover, we found that allo-SCT improved OS for AML patients with high PARP10 expression but not for patients with low PARP10 expression, while allo-SCT decreased EFS for patients with low PARP10 expression. Finally, we confirmed that PARP10 knockout impaired AML cell proliferation in vitro. In summary, our data suggested that PARP10 is aberrantly expressed in AML, and high expression of PARP10 might be a biomarker for poor prognosis and also a potential indicator for allo-SCT therapy, which might provide precise treatment indications for physicians.
    Keywords:  PARP10; acute myeloid leukemia; biomarker; prognosis
    DOI:  https://doi.org/10.18632/aging.204832
  34. Blood Cancer J. 2023 Jul 28. 13(1): 115
    Survival expectation after thrombosis and overt-myelofibrosis in essential thrombocythemia and prefibrotic myelofibrosis: a multistate model approach.
    Alessandra Carobbio, Alessandro Maria Vannucchi, Elisa Rumi, Valerio De Stefano, Alessandro Rambaldi, Giuseppe Carli, Maria Luigia Randi, Heinz Gisslinger, Francesco Passamonti, Juergen Thiele, Naseema Gangat, Ayalew Tefferi, Tiziano Barbui.
      
    DOI:  https://doi.org/10.1038/s41408-023-00887-7
  35. Clin Lab Med. 2023 09;pii: S0272-2712(23)00045-8. [Epub ahead of print]43(3): 411-426
    Clinical Flow Cytometry Analysis in the Setting of Chronic Myeloid Neoplasms and Clonal Hematopoiesis.
    Siba El Hussein, Sanam Loghavi.
      The utility of flow cytometry analysis in the evaluation of chronic myeloid neoplasms, such as myelodysplastic neoplasms and chronic myeloproliferative neoplasms, continues to be emphasized and explored. Recently flow cytometry analysis has been also proven to be able to distinguish persistent clonal hematopoiesis from measurable residual disease in patients with acute myeloid leukemia (AML), a finding with potential critical treatment impact in the management of patients with AML.
    Keywords:  CCUS; CHIP; Clonal hematopoiesis; Flow cytometry analysis; Myelodysplastic neoplasms; Myeloproliferative neoplasms
    DOI:  https://doi.org/10.1016/j.cll.2023.04.007
  36. Front Vet Sci. 2023 ;10 1182197
    Investigation of the impact of clonal hematopoiesis on severity and pathophysiology of COVID-19 in rhesus macaques.
    Tae-Hoon Shin, Yifan Zhou, Byung-Chul Lee, So Gun Hong, Shayne F Andrew, Barbara J Flynn, Matthew Gagne, John-Paul M Todd, Ian N Moore, Anthony Cook, Mark G Lewis, Kathryn E Foulds, Robert A Seder, Daniel C Douek, Mario Roederer, Cynthia E Dunbar.
      Clinical manifestations of COVID-19 vary widely, ranging from asymptomatic to severe respiratory failure with profound inflammation. Although risk factors for severe illness have been identified, definitive determinants remain elusive. Clonal hematopoiesis (CH), the expansion of hematopoietic stem and progenitor cells bearing acquired somatic mutations, is associated with advanced age and hyperinflammation. Given the similar age range and hyperinflammatory phenotype between frequent CH and severe COVID-19, CH could impact the risk of severe COVID-19. Human cohort studies have attempted to prove this relationship, but conclusions are conflicting. Rhesus macaques (RMs) are being utilized to test vaccines and therapeutics for COVID-19. However, RMs, even other species, have not yet been reported to develop late inflammatory COVID-19 disease. Here, RMs with either spontaneous DNMT3A or engineered TET2 CH along with similarly transplanted and conditioned controls were infected with SARS-CoV-2 and monitored until 12 days post-inoculation (dpi). Although no significant differences in clinical symptoms and blood counts were noted, an aged animal with natural DNMT3A CH died on 10 dpi. CH macaques showed evidence of sustained local inflammatory responses compared to controls. Interestingly, viral loads in respiratory tracts were higher at every timepoint in the CH group. Lung sections from euthanasia showed evidence of mild inflammation in all animals, while viral antigen was more frequently detected in the lung tissues of CH macaques even at the time of autopsy. Despite the lack of striking inflammation and serious illness, our findings suggest potential pathophysiological differences in RMs with or without CH upon SARS-CoV-2 infection.
    Keywords:  COVID-19; SARS-CoV-2; aging; clonal hematopoiesis; hyperinflammation; rhesus macaque
    DOI:  https://doi.org/10.3389/fvets.2023.1182197
  37. Sci Rep. 2023 07 24. 13(1): 11908
    Loss of Nudt15 thiopurine detoxification increases direct DNA damage in hematopoietic stem cells.
    Noriaki Yamashita, Masahiro Kawahara, Takayuki Imai, Goichi Tatsumi, Ai Asai-Nishishita, Akira Andoh.
      Thiopurines, such as 6-mercaptopurine (6-MP), are widely used as cytotoxic agents and immunosuppressants for leukemia and autoimmune or inflammatory diseases. A nonsynonymous single nucleotide polymorphism (p.Arg139Cys; R139C) of the nucleoside diphosphate-linked moiety X-type motif 15 (NUDT15) gene causes the loss of thiopurine detoxification, inducing myelosuppression. To understand such hematotoxicity, we investigate the effects of NUDT15 R139C on hematopoietic stem cells (HSCs) upon thiopurine administration. Using previously established Nudt15R138C knock-in mice, which mimic myelosuppression in NUDT15R139C homozygous or heterozygous patients following thiopurine administration, we investigated the numerical changes of HSCs and hematopoietic progenitor cells following 6-MP administration using in vivo flowcytometry and ex vivo HSC expansion. Genes differentially expressed between Nudt15+/+ HSCs and Nudt15R138C/R138C HSCs were identified using RNA-sequencing before the emergence of 6-MP-induced HSC-damage. Gene Ontology (GO) and Transcriptional Regulatory Relationships Unraveled by Sentence-based Text Mining (TRRUST) analyses were performed to elucidate the molecular effects of 6-MP on HSCs. In Nudt15R138C/R138C mice, 6-MP induced exhaustion of HSCs faster than that of multipotent progenitors and as fast as that of myeloid-committed progenitors. Ex vivo-expanded Nudt15R138C/R138C HSCs were dose- and time-dependently damaged by 6-MP. GO analysis identified the DNA damage response and cell cycle process as the most strongly influenced processes in Nudt15R138C/R138C HSCs. TRRUST analysis revealed that the Trp53-regulated transcriptional regulatory network is influenced prior to HSC exhaustion in Nudt15R138C/R138C HSCs. The loss of NUDT15 thiopurine detoxification enhances thiopurine-mediated DNA damage via the Trp53 networks in HSCs. Therefore, caution is required in long-term thiopurine use in patients with NUDT15 R139C in view of its adverse effects on HSCs in the form of DNA damage.
    DOI:  https://doi.org/10.1038/s41598-023-38952-7
  38. Leukemia. 2023 Jul 28.
    WT1 and PRAME RNA-loaded dendritic cell vaccine as maintenance therapy in de novo AML after intensive induction chemotherapy.
    Yngvar Fløisand, Mats Remberger, Iris Bigalke, Dag Josefsen, Helen Vålerhaugen, Else Marit Inderberg, Richard W Olaussen, Bjørn Tore Gjertsen, Rene Goedkoop, Christiane Geiger, Petra U Prinz, Frauke M Schnorfeil, Kai Pinkernell, Dolores J Schendel, Gunnar Kvalheim.
      Intensive induction chemotherapy achieves complete remissions (CR) in >60% of patients with acute myeloid leukemia (AML) but overall survival (OS) is poor for relapsing patients not eligible for allogeneic hematopoietic stem cell transplantation (allo-HSCT). Oral azacytidine may be used as maintenance treatment in AML in first remission, but can be associated with substantial side effects, and less toxic strategies should be explored. Twenty AML patients in first CR (CR1) ineligible for allo-HSCT were treated with FDC101, an autologous RNA-loaded mature dendritic cell (mDC) vaccine expressing two leukemia-associated antigens (LAAs). Each dose consisted of 2.5-5 × 106 mDCs per antigen, given weekly until week 4, at week 6, and then monthly, during the 2-year study period. Patients were followed for safety and long-term survival. Treatment was well tolerated, with mild and transient injection site reactions. Eleven of 20 patients (55%) remained in CR, while 4 of 6 relapsing patients achieved CR2 after salvage therapy and underwent allo-HSCT. OS at five years was 75% (95% CI: 50-89), with 70% of patients ≥60 years of age being long-term survivors. Maintenance therapy with this DC vaccine was well tolerated in AML patients in CR1 and was accompanied by encouraging 5-year long-term survival.
    DOI:  https://doi.org/10.1038/s41375-023-01980-3
  39. Blood. 2023 Jul 27. 142(4): 309-311
    ZDHHC21: a mitochondrial vulnerability in AML.
    Aaron D Schimmer.
      
    DOI:  https://doi.org/10.1182/blood.2023021129
  40. J Am Heart Assoc. 2023 Jul 25. e030603
    Clonal Hematopoiesis of Indeterminate Potential From a Heart Failure Specialist's Point of View.
    Maurits A Sikking, Sophie L V M Stroeks, Olivia J Waring, Michiel T H M Henkens, Niels P Riksen, Alexander Hoischen, Stephane R B Heymans, Job A J Verdonschot.
      Clonal hematopoiesis of indeterminate potential (CHIP) is a common bone marrow abnormality induced by age-related DNA mutations, which give rise to proinflammatory immune cells. These immune cells exacerbate atherosclerotic cardiovascular disease and may induce or accelerate heart failure. The mechanisms involved are complex but point toward a central role for proinflammatory macrophages and an inflammasome-dependent immune response (IL-1 [interleukin-1] and IL-6 [interleukin-6]) in the atherosclerotic plaque or directly in the myocardium. Intracardiac inflammation may decrease cardiac function and induce cardiac fibrosis, even in the absence of atherosclerotic cardiovascular disease. The pathophysiology and consequences of CHIP may differ among implicated genes as well as subgroups of patients with heart failure, based on cause (ischemic versus nonischemic) and ejection fraction (reduced ejection fraction versus preserved ejection fraction). Evidence is accumulating that CHIP is associated with cardiovascular mortality in ischemic and nonischemic heart failure with reduced ejection fraction and involved in the development of heart failure with preserved ejection fraction. CHIP and corresponding inflammatory pathways provide a highly potent therapeutic target. Randomized controlled trials in patients with well-phenotyped heart failure, where readily available anti-inflammatory therapies are used to intervene with clonal hematopoiesis, may pave the way for a new area of heart failure treatment. The first clinical trials that target CHIP are already registered.
    Keywords:  atherosclerotic cardiovascular disease; clonal hematopoiesis; heart failure; inflammation
    DOI:  https://doi.org/10.1161/JAHA.123.030603
  41. J Hematol Oncol. 2023 Jul 27. 16(1): 82
    Ten years of treatment with ruxolitinib for myelofibrosis: a review of safety.
    Srdan Verstovsek, Ruben A Mesa, Robert A Livingston, Wilson Hu, John Mascarenhas.
      Myelofibrosis (MF) is a chronic myeloproliferative neoplasm characterized by bone marrow fibrosis, anemia, extramedullary hematopoiesis, and splenomegaly. Patients with MF are at risk for reduced survival versus the general population and often experience burdensome signs and symptoms that reduce quality of life. The oral Janus kinase (JAK) 1/JAK2 inhibitor ruxolitinib was initially approved by the US Food and Drug Administration in 2011 for the treatment of patients with intermediate or high-risk MF, including primary MF, post-polycythemia vera MF, and post-essential thrombocythemia MF, based on efficacy and safety findings from the randomized, controlled, phase 3 COMFORT trials. Over a decade later, ruxolitinib continues to be the standard of care in higher-risk MF, and dose optimization and management remain crucial for safely maximizing clinical benefits of ruxolitinib. This review summarizes the safety profile of ruxolitinib in patients with MF in the COMFORT trials leading up to approval and in the subsequent JUMP, ROBUST, EXPAND, and REALISE trials; in pooled analyses; and in postmarketing analyses in the 10 years following approval. There is a focus on the occurrence of common hematologic and nonhematologic adverse events, with guidance provided on the management of patients with anemia or thrombocytopenia, including dosing strategies based on findings from the REALISE and EXPAND trials. Finally, to ensure a greater understanding of the safety profile of ruxolitinib, practical considerations are discussed.
    Keywords:  Janus kinase; Myelofibrosis; Myeloproliferative neoplasm; Ruxolitinib; Safety
    DOI:  https://doi.org/10.1186/s13045-023-01471-z
  42. Br J Haematol. 2023 Jul 22.
    Immune modulation in chronic myeloid leukaemia patients treated with nilotinib and interferon-alpha.
    Yazad D Irani, Amy Hughes, Chung H Kok, Jade Clarson, David T Yeung, David M Ross, Susan Branford, Timothy P Hughes, Agnes S M Yong.
      The addition of interferon to tyrosine kinase inhibitors (TKIs), to improve deep molecular response (DMR) and potentially treatment-free remission (TFR) rates in chronic-phase chronic myeloid leukaemia (CP-CML) patients is under active investigation. However, the immunobiology of this combination is poorly understood. We performed a comprehensive longitudinal assessment of immunological changes in CML patients treated with nilotinib and interferon-alpha (IFN-α) within the ALLG CML11 trial (n = 12) or nilotinib alone (n = 17). We demonstrate that nilotinib+IFN transiently reduced absolute counts of natural killer (NK) cells, compared with nilotinib alone. Furthermore, CD16+ -cytolytic and CD57+ CD62L- -mature NK cells were transiently reduced during IFN therapy, without affecting NK-cell function. IFN transiently increased cytotoxic T-lymphocyte (CTL) responses to leukaemia-associated antigens (LAAs) proteinase-3, BMI-1 and PRAME; and had no effect on regulatory T cells, or myeloid-derived suppressor cells. Patients on nilotinib+IFN who achieved MR4.5 by 12 months had a significantly higher proportion of NK cells expressing NKp46, NKp30 and NKG2D compared with patients not achieving this milestone. This difference was not observed in the nilotinib-alone group. The addition of IFN to nilotinib drives an increase in NK-activating receptors, CTLs responding to LAAs and results in transient immune modulation, which may influence earlier DMR, and its effect on long-term outcomes warrants further investigation.
    Keywords:  CML; immunobiology; interferon; nilotinib
    DOI:  https://doi.org/10.1111/bjh.18984
  43. Blood Cancer Discov. 2023 Jul 27. OF1-OF13
    Next-Generation JAK2 Inhibitors for the Treatment of Myeloproliferative Neoplasms: Lessons from Structure-Based Drug Discovery Approaches.
    Pramod C Nair, Jacob Piehler, Denis Tvorogov, David M Ross, Angel F Lopez, Jason Gotlib, Daniel Thomas.
      Selective inhibitors of Janus kinase (JAK) 2 have been in demand since the discovery of the JAK2 V617F mutation present in patients with myeloproliferative neoplasms (MPN); however, the structural basis of V617F oncogenicity has only recently been elucidated. New structural studies reveal a role for other JAK2 domains, beyond the kinase domain, that contribute to pathogenic signaling. Here we evaluate the structure-based approaches that led to recently-approved type I JAK2 inhibitors (fedratinib and pacritinib), as well as type II (BBT594 and CHZ868) and pseudokinase inhibitors under development (JNJ7706621). With full-length JAK homodimeric structures now available, superior selective and mutation-specific JAK2 inhibitors are foreseeable.SIGNIFICANCE: The JAK inhibitors currently used for the treatment of MPNs are effective for symptom management but not for disease eradication, primarily because they are not strongly selective for the mutant clone. The rise of computational and structure-based drug discovery approaches together with the knowledge of full-length JAK dimer complexes provides a unique opportunity to develop better targeted therapies for a range of conditions driven by pathologic JAK2 signaling.
    DOI:  https://doi.org/10.1158/2643-3230.BCD-22-0189
  44. Ann Hematol. 2023 Jul 22.
    One disease, two faces: clonally-related AML and MPDCP with skin involvement.
    Giovanni Martino, Gaetano Cimino, Matteo Caridi, Giuseppe Perta, Valeria Cardinali, Sofia Sciabolacci, Martina Quintini, Caterina Matteucci, Stefano Ascani, Cristina Mecucci, Maria Paola Martelli.
      
    DOI:  https://doi.org/10.1007/s00277-023-05377-1
  45. Leukemia. 2023 Jul 28.
    The JAK1/2 inhibitor ruxolitinib in patients with COVID-19 triggered hyperinflammation: the RuxCoFlam trial.
    J Hammersen, S Birndt, K Döhner, P Reuken, A Stallmach, P Sauerbrey, F La Rosée, M Pfirrmann, C Fabisch, M Weiss, K Träger, H Bremer, S Russo, G Illerhaus, D Drömann, S Schneider, P La Rosée, A Hochhaus.
      Dysregulated hyperinflammatory response is key in the pathogenesis in patients with severe COVID-19 leading to acute respiratory distress syndrome and multiorgan failure. Whilst immunosuppression has been proven to be effective, potential biological targets and optimal timing of treatment are still conflicting. We sought to evaluate efficacy and safety of the Janus Kinase 1/2 inhibitor ruxolitinib, employing the previously developed COVID-19 Inflammation Score (CIS) in a prospective multicenter open label phase II trial (NCT04338958). Primary objective was reversal of hyperinflammation (CIS reduction of ≥25% at day 7 in ≥20% of patients). In 184 patients with a CIS of ≥10 (median 12) ruxolitinib was commenced at an initial dose of 10 mg twice daily and applied over a median of 14 days (range, 2-31). On day 7, median CIS declined to 6 (range, 1-13); 71% of patients (CI 64-77%) achieved a ≥25% CIS reduction accompanied by a reduction of markers of inflammation. Median cumulative dose was 272.5 mg/d. Treatment was well tolerated without any grade 3-5 adverse events related to ruxolitinib. Forty-four patients (23.9%) died, all without reported association to study drug. In conclusion, ruxolitinib proved to be safe and effective in a cohort of COVID-19 patients with defined hyperinflammation.
    DOI:  https://doi.org/10.1038/s41375-023-01979-w
  46. Dev Cell. 2023 Jul 18. pii: S1534-5807(23)00331-3. [Epub ahead of print]
    Parallel CRISPR-Cas9 screens identify mechanisms of PLIN2 and lipid droplet regulation.
    Melissa A Roberts, Kirandeep K Deol, Alyssa J Mathiowetz, Mike Lange, Dara E Leto, Julian Stevenson, Sayed Hadi Hashemi, David W Morgens, Emilee Easter, Kartoosh Heydari, Mike A Nalls, Michael C Bassik, Martin Kampmann, Ron R Kopito, Faraz Faghri, James A Olzmann.
      Despite the key roles of perilipin-2 (PLIN2) in governing lipid droplet (LD) metabolism, the mechanisms that regulate PLIN2 levels remain incompletely understood. Here, we leverage a set of genome-edited human PLIN2 reporter cell lines in a series of CRISPR-Cas9 loss-of-function screens, identifying genetic modifiers that influence PLIN2 expression and post-translational stability under different metabolic conditions and in different cell types. These regulators include canonical genes that control lipid metabolism as well as genes involved in ubiquitination, transcription, and mitochondrial function. We further demonstrate a role for the E3 ligase MARCH6 in regulating triacylglycerol biosynthesis, thereby influencing LD abundance and PLIN2 stability. Finally, our CRISPR screens and several published screens provide the foundation for CRISPRlipid (http://crisprlipid.org), an online data commons for lipid-related functional genomics data. Our study identifies mechanisms of PLIN2 and LD regulation and provides an extensive resource for the exploration of LD biology and lipid metabolism.
    Keywords:  CRISPR; ERAD; MARCH6; PLIN2; endoplasmic reticulum; genetic screen; lipid droplet; metabolism; perilipin; resource
    DOI:  https://doi.org/10.1016/j.devcel.2023.07.001
This page is being maintained by Thomas Krichel. It was last updated on 2023‒07‒30 at 4:32.