bims-tremyl 2024-07-14 papers

on Therapy resistance biology in myeloid leukemia

Issue of 2024–07–14
forty-one papers selected by
Paolo Gallipoli, Barts Cancer Institute, Queen Mary University of London

Myelofibrosis management in routine clinical practice with a focus on patients with cytopenias: recommendations from a global consensus group.
Characterization of Cases with the Rare Cytogenetic Abnormality i(7)(p10) Reveals an Association with IDH2 Mutated AML.
Risk Prediction for Clonal Cytopenia: Multicenter Real-World Evidence.
Inhibitors of the tyrosine kinases FMS-like tyrosine kinase-3 and WEE1 induce apoptosis and DNA damage synergistically in acute myeloid leukemia cells.
Updates in biology, classification, and management of acute myeloid leukemia with antecedent hematologic disorder and therapy related acute myeloid leukemia.
Health-related quality of life and symptoms of chronic myeloid leukemia patients after discontinuation of tyrosine kinase inhibitors: results from the EURO-SKI Trial.
How I Treat: Differentiation Therapy in Acute Myeloid Leukemia.
How complete must an AML remission be?
Differential inflammatory conditioning of the bone marrow by acute myeloid leukemia and its impact on progression.
Germline ERG haploinsufficiency defines a new syndrome with cytopenia and hematological malignancy predisposition.
In Fanconi Anemia, impaired accumulation of bone marrow neutrophils during emergency granulopoiesis induces hematopoietic stem cell stress.
Bioengineered niches that recreate physiological extracellular matrix organisation to support long-term haematopoietic stem cells.
Endomucin marks quiescent long-term multi-lineage repopulating hematopoietic stem cells and is essential for their transendothelial migration.
CREST-UK: Real-world effectiveness, safety and outpatient delivery of CPX-351 for first-line treatment of newly diagnosed therapy-related AML and AML with myelodysplasia-related changes in the UK.
Mechanisms of response and tolerance to active RAS inhibition in KRAS-mutant NSCLC.
Evaluating the role of Day 14 bone marrow biopsy and European LeukemiaNet risk classification in predicting overall and relapse-free survival in acute myeloid leukemia.
Altered RNA export by SF3B1 mutants confers sensitivity to nuclear export inhibition.
Symptomatic Heart Failure and Clonal Hematopoiesis-related Mutations in Patients with Acute Myeloid Leukemia.
New frameworks for hematopoiesis derived from single-cell genomics.
Sorafenib maintenance in FLT3-ITD mutated AML after allogeneic HCT: a real-world, single-center experience.
Pretransplant desensitization of donor-specific anti-HLA antibodies with plasmapheresis and immunoglobulin produces equivalent outcomes to patients with no donor specific antibodies in haploidentical hematopoietic cell transplant.
Decoding Endothelial MPL and JAK2V617F Mutation: Insight Into Cardiovascular Dysfunction in Myeloproliferative Neoplasms.
Prognostic and therapeutic implications of TP53 expression in chronic myelomonocytic leukemia.
Multiple small-dose infusions of G-CSF-mobilized haploidentical lymphocytes after autologous haematopoietic stem cell transplantation for acute myeloid leukaemia.
The Gordian knot: ruxolitinib or transplants for high-risk myelofibrosis.
Momelotinib versus Continued Ruxolitinib or Best Available Therapy in JAK Inhibitor-Experienced Patients with Myelofibrosis and Anemia: Subgroup Analysis of SIMPLIFY-2.
Epigenetic alterations affecting hematopoietic regulatory networks as drivers of mixed myeloid/lymphoid leukemia.
CRISPR-based rapid molecular diagnostic tests for fusion-driven leukemias.
Glutathione determines chronic myeloid leukemia vulnerability to an inhibitor of CMPK and TMPK.
Plasmacytoid dendritic cells control homeostasis of megakaryopoiesis.
Targeting HMGCS1 restores chemotherapy sensitivity in acute myeloid leukemia.
Treatment challenges and outcomes of older patients with acute myeloid leukemia from India.
Mutant IDH1 inhibition induces dsDNA sensing to activate tumor immunity.
Phase II study of a longitudinal rehabilitation program for allogeneic blood and marrow transplantation patients.
Outcomes with low dose anti-thymocyte globulin based graft versus host disease prophylaxis after mismatched unrelated donor allogeneic hematopoietic cell transplantation.
In Utero Hematopoietic Stem Cell Transplantation for Fanconi Anemia.
Clonal Hematopoiesis in Patients With Neuroendocrine Tumor Treated With Lutetium-177 and the Risk of Thrombocytopenia: A Prospective Study.
The RNA helicases DDX19A/B modulate selinexor sensitivity by regulating MCL1 mRNA nuclear export in leukemia cells.
PARG is essential for Polθ-mediated DNA end-joining by removing repressive poly-ADP-ribose marks.
tRNA m1A modification regulate HSC maintenance and self-renewal via mTORC1 signaling.
Structural screening and molecular simulation identify potential ligands against the K700E hot spot variant and functional pockets of SF3B1 to modulate splicing in myelodysplastic syndrome.

Leukemia. 2024 Jul 09.

Myelofibrosis management in routine clinical practice with a focus on patients with cytopenias: recommendations from a global consensus group.

Steffen Koschmieder, Prithviraj Bose, Martin H Ellis, Vikas Gupta, Jean-Jacques Kiladjian, John Mascarenhas, Vikram Mathews, Francesco Passamonti, Claire Harrison.

DOI: https://doi.org/10.1038/s41375-024-02330-7
Blood Adv. 2024 Jun 14. pii: bloodadvances.2024013225. [Epub ahead of print]

Characterization of Cases with the Rare Cytogenetic Abnormality i(7)(p10) Reveals an Association with IDH2 Mutated AML.

Anna Stengel, Katharina Hörst, Constanze Kühn, Manja Meggendorfer, Wolfgang Kern, Torsten Haferlach, Claudia Haferlach.

DOI: https://doi.org/10.1182/bloodadvances.2024013225
Blood. 2024 Jul 12. pii: blood.2024024756. [Epub ahead of print]

Risk Prediction for Clonal Cytopenia: Multicenter Real-World Evidence.

Zhuoer Xie, Rami S Komrokji, Najla Al-Ali, Alexandra Regelson, Susan Geyer, Anand A Patel, Caner Saygin, Amer M Zeidan, Jan Philipp Bewersdorf, Lourdes M Mendez, Ashwin Kishtagari, Joshua F Zeidner, Catherine C Coombs, Yazan F Madanat, Stephen S Chung, Talha Badar, James M Foran, Pinkal Desai, Charlton Tsai, Elizabeth A Griffiths, Monzr M Al Malki, Idoroenyi Amanam, Catherine Lai, H Joachim Deeg, Lionel Ades, Cecilia Arana-Yi, Afaf Eg Osman, Shira Naomi Dinner, Yasmin Abaza, Justin Taylor, Namrata S Chandhok, Deborah Soong, Andrew M Brunner, Hetty E Carraway, Abhay Singh, Chiara Elena, Jacqueline Ferrari, Anna Galli, Sara Pozzi, Eric Padron, Mrinal M Patnaik, Luca Malcovati, Michael R Savona, Aref Al-Kali.

Clonal cytopenia of undetermined significance (CCUS) represents a distinct disease entity characterized by myeloid-related somatic mutations with a variant allele fraction of ≥2% in individuals with unexplained cytopenia(s) but without a myeloid neoplasm (MN). Notably, CCUS carries a risk of progressing to MN, particularly in cases featuring high-risk mutations. Understanding CCUS requires dedicated studies to elucidate its risk factors and natural history. Our analysis of 357 CCUS patients investigated the interplay between clonality, cytopenia, and prognosis. Multivariate analysis identified 3 key adverse prognostic factors: the presence of splicing mutation(s) (score = 2 points), platelet count <100×109/L (score = 2.5), and ≥2 mutations (score = 3). Variable scores were based on the coefficients from the Cox proportional hazards model. This led to the development of the Clonal Cytopenia Risk Score (CCRS), which stratified patients into low- (score <2.5 points), intermediate- (score 2.5-<5), and high-risk (score ≥5) groups. The CCRS effectively predicted 2-year cumulative incidence of MN for low- (6.4%), intermediate- (14.1%), and high- (37.2%) risk groups, respectively, by Gray's test (P <.0001). We further validated the CCRS by applying it to an independent CCUS cohort of 104 patients, demonstrating a c-index of 0.64 (P =.005) in stratifying the cumulative incidence of MN. Our study underscores the importance of integrating clinical and molecular data to assess the risk of CCUS progression, making the CCRS a valuable tool that is practical and easily calculable. These findings are clinically relevant, shaping the management strategies for CCUS and informing future clinical trial designs.

DOI: https://doi.org/10.1182/blood.2024024756
Biomed Pharmacother. 2024 Jul 05. pii: S0753-3322(24)00960-0. [Epub ahead of print]177 117076

Inhibitors of the tyrosine kinases FMS-like tyrosine kinase-3 and WEE1 induce apoptosis and DNA damage synergistically in acute myeloid leukemia cells.

Christoph Hieber, Al-Hassan M Mustafa, Sarah Neuroth, Sven Henninger, Hans-Peter Wollscheid, Joanna Zabkiewicz, Michelle Lazenby, Caroline Alvares, Siavosh Mahboobi, Falk Butter, Walburgis Brenner, Matthias Bros, Oliver H Krämer.

  Hyperactive FMS-like receptor tyrosine kinase-3 mutants with internal tandem duplications (FLT3-ITD) are frequent driver mutations of aggressive acute myeloid leukemia (AML). Inhibitors of FLT3 produce promising results in rationally designed cotreatment schemes. Since FLT3-ITD modulates DNA replication and DNA repair, valid anti-leukemia strategies could rely on a combined inhibition of FLT3-ITD and regulators of cell cycle progression and DNA integrity. These include the WEE1 kinase which controls cell cycle progression, nucleotide synthesis, and DNA replication origin firing. We investigated how pharmacological inhibition of FLT3 and WEE1 affected the survival and genomic integrity of AML cell lines and primary AML cells. We reveal that promising clinical grade and preclinical inhibitors of FLT3 and WEE1 synergistically trigger apoptosis in leukemic cells that express FLT3-ITD. An accumulation of single and double strand DNA damage precedes this process. Mass spectrometry-based proteomic analyses show that FLT3-ITD and WEE1 sustain the expression of the ribonucleotide reductase subunit RRM2, which provides dNTPs for DNA replication. Unlike their strong pro-apoptotic effects on leukemia cells with FLT3-ITD, inhibitors of FLT3 and WEE1 do not damage healthy human blood cells and murine hematopoietic stem cells. Thus, pharmacological inhibition of FLT3-ITD and WEE1 might become an improved, rationally designed therapeutic option.

Keywords:  AML; DNA replication stress; FLT3-ITD; Inhibitors; Synergism; WEE1

DOI:  https://doi.org/10.1016/j.biopha.2024.117076
Leuk Res. 2024 Jun 29. pii: S0145-2126(24)00112-7. [Epub ahead of print]144 107546

Updates in biology, classification, and management of acute myeloid leukemia with antecedent hematologic disorder and therapy related acute myeloid leukemia.

Kanak Parmar, Rupayan Kundu, Abhishek Maiti, Somedeb Ball.

  Acute myeloid leukemia with antecedent hematologic disorder (AHD-AML) and therapy related AML (t-AML) constitute a heterogenous disease with inferior outcomes. It is often characterized by high-risk cytogenetic and molecular alterations associated with AHD or prior cancer therapy. Historically, the standard of care treatment has been intensive induction with "7 + 3", with an improved overall response rate and survival with CPX-351. Results from large registry-based studies suggested that allogeneic hematopoietic stem cell transplant is preferable to consolidation chemotherapy alone for achieving long-term survival in patients with AHD-AML. Prevalence of high-risk genetic features and advanced age and comorbidities in patients make AHD-AML and t-AML clinically challenging subgroups to treat with intensive approaches. Recent reports on less intensive treatment options, particularly the hypomethylating agent-venetoclax combination, have shown encouraging response rates in these patients. However, emerging resistance mechanisms compromise duration of response and overall survival. Several novel agents targeting apoptotic machinery, signaling pathways, and immune checkpoints are under clinical investigation, with an aim to truly improve overall outcomes in this subgroup. We reviewed updates in biology, classification, and clinical data comparing safety and efficacy of intensive and less intensive treatment options, and summarized ongoing studies with promising novel therapies in AHD-AML and t-AML.

Keywords:  AML myelodysplasia related; AML with MDS related gene mutations; Blast phase MPN; ELN 2022; Venetoclax; WHO 2022

DOI:  https://doi.org/10.1016/j.leukres.2024.107546
Leukemia. 2024 Jul 10.

Health-related quality of life and symptoms of chronic myeloid leukemia patients after discontinuation of tyrosine kinase inhibitors: results from the EURO-SKI Trial.

Fabio Efficace, Francois-Xavier Mahon, Johan Richter, Alfonso Piciocchi, Marta Cipriani, Franck E Nicolini, Jiri Mayer, Daniela Zackova, Jeroen J W M Janssen, Panayiotis Panayiotidis, Hanne Vestergaard, Perttu Koskenvesa, Antonio Almeida, Henrik Hjorth-Hansen, Joaquin Martinez-Lopez, Ulla Olsson-Strömberg, Andreas Hochhaus, Marc G Berger, Gabriel Etienne, Hana Klamova, Edgar Faber, Philippe Rousselot, Markus Pfirrmann, Susanne Saussele.

Limited data is available on the health-related quality of life (HRQoL) and symptoms of patients with chronic myeloid leukemia (CML) who are in treatment-free remission (TFR). We herein report HRQoL results from the EURO-SKI trial. Patients who had been on tyrosine kinase inhibitors (TKIs) therapy for at least 3 years and achieved MR4 for at least 1 year were enrolled from 11 European countries, and the EORTC QLQ-C30 and the FACIT-Fatigue questionnaires were used to assess HRQoL and fatigue respectively. Patients were categorized into the following age groups: 18-39, 40-59, 60-69 and ≥70 years. Of 728 patients evaluated at baseline, 686 (94%) completed HRQoL assessments. The median age at TKI discontinuation was 60 years. Our findings indicate that HRQoL and symptom trajectories may vary depending on specific age groups, with younger patients benefiting the most. Improvements in patients aged 60 years or older were marginal across several HRQoL and symptom domains. At the time of considering TKI discontinuation, physicians could inform younger patients that they may expect valuable HRQoL benefits. Considering the marginal improvements observed in patients aged 60 years or above, it may be important to further investigate the value of TFR compared to a lowest effective dose approach in this older group of patients.

DOI: https://doi.org/10.1038/s41375-024-02341-4
Blood. 2024 Jul 08. pii: blood.2024024008. [Epub ahead of print]

How I Treat: Differentiation Therapy in Acute Myeloid Leukemia.

Ghayas C Issa, Eytan M Stein, Courtney D D DiNardo.

An increasing number of acute myeloid leukemia (AML) therapeutics have been developed, not as cytotoxic therapies, but rather as targeted agents able to restore the aberrant and leukemogenic "block" in normal differentiation. All-trans retinoic acid (ATRA) and arsenic trioxide (ATO) are classic examples of differentiating agents for treatment of acute promyelocytic leukemia (APL); newer therapies functioning through differentiation include isocitrate dehydrogenase (IDH) 1 and 2 inhibitors, FMS-like tyrosine kinase 3 (FLT3) inhibitors, and menin inhibitors. The terminal differentiation of leukemic blasts via differentiating agent therapy can lead to a constellation of signs and symptoms, originally referred to as "retinoic acid syndrome" and now termed "differentiation syndrome" (DS), characterized predominantly by systemic inflammatory response system (SIRS)-like features of dyspnea, pulmonary infiltrates, pleural and pericardial effusions, unexplained fevers, hypotension, edema, and renal insufficiency. DS in patients with newly diagnosed APL is generally straightforward to identify, however DS in patients with multiply relapsed AML can be more challenging to diagnose, due to non-specific signs and symptoms which can be mistakenly attributed to infectious etiologies or the underlying refractory leukemia itself. Prompt consideration of DS, rapid initiation of systemic corticosteroids, and early cytoreduction in the setting of concomitant hyperleukocytosis, are essential for optimal management.

DOI: https://doi.org/10.1182/blood.2024024008
Blood. 2024 Jul 11. 144(2): 131-132

How complete must an AML remission be?

Christopher S Hourigan.

DOI: https://doi.org/10.1182/blood.2024024826
Blood Adv. 2024 Jul 12. pii: bloodadvances.2024012867. [Epub ahead of print]

Differential inflammatory conditioning of the bone marrow by acute myeloid leukemia and its impact on progression.

Valentina R Minciacchi, Christina Karantanou, Jimena Bravo, Raquel S Pereira, Costanza Zanetti, Theresa Krack, Rahul Kumar, Katrin Bankov, Sylvia Hartmann, Brian Jp Huntly, Eshwar Meduri, Wolfram Ruf, Daniela S Krause.

Inflammation promotes solid tumor progression, but how regulatory mechanisms of inflammation may impact leukemia is less well studied. Using annexin A5 (ANXA 5), a calcium-binding protein known for apoptosis, which we discovered to be differentially expressed in the bone marrow microenvironment (BMM) of mice with acute myeloid (AML) versus chronic myeloid leukemia, as a model system, we unravel here a circuit in which AML-derived tumor necrosis factor (TNF)α dose-dependently reduces ANXA5 in the BMM. This creates an inflammatory BMM via elevated levels of prostaglandin E2 (PGE2). Via binding to its EP4 receptor, PGE2 increases -catenin and hypoxia-inducible factor (HIF) 1 α signaling in AML cells, thereby accelerating PGE2-sensitive AML. Human trephine biopsies may show lower ANXA5 expression and higher PGE2 expression in AML compared to other hematological malignancies. Further, syngeneic and xenogeneic transplantation models suggest a survival benefit after treatment with the inhibitor of prostaglandin-endoperoxide synthase 2 (cyclooxygenase 2 (COX2)), celecoxib, plus cytarabine in those AML types highly sensitive to PGE2 compared to cytarabine alone. Taken together, TNFα/ANXA5/NF-kB/COX2/PGE2-mediated inflammation influences AML course in a highly differential and circular manner, and AML patients with 'inflammatory AML' may benefit from antiphlogistic agents as adjunct therapy.

DOI: https://doi.org/10.1182/bloodadvances.2024012867
Blood. 2024 Jul 11. pii: blood.2024024607. [Epub ahead of print]

Germline ERG haploinsufficiency defines a new syndrome with cytopenia and hematological malignancy predisposition.

Jiarna Rose Zerella, Claire C Homan, Peer Arts, Xuzhu Lin, Sam John Spinelli, Parvathy Venugopal, Milena Babic, Peter Brautigan, Lynda Truong, Luis Alberto Arriola-Martinez, Sarah Moore, Rachel Hollins, Wendy Parker, Hung Nguyen, Karin S Kassahn, Susan Branford, Simone K Feurstein, Lise Larcher, Flore Sicre de Fontbrune, Serwet Demirdas, Sonja de Munnik, Hélène A Poirel, Benedicte Brichard, Sahar Mansour, Kristiana Gordon, Erg Variants Research Network, Marcin W Wlodarski, Ashwin Lakshman Koppayi, Sara Dobbins, Pim G N J Mutsaers, Kim E Nichols, Ninad Oak, Desiree DeMille, Rong Mao, Ali Crawford, Julie McCarrier, Donald Basel, Josue Flores-Daboub, Michael W Drazer, Kerry Phillips, Nicola Poplawski, Graeme M Birdsey, Daniela Pirri, Pia Ostergaard, Annet Simons, Lucy A Godley, David M Ross, Devendra K Hiwase, Jean Soulier, Anna L Brown, Catherine L Carmichael, Hamish S Scott, Christopher N Hahn.

The genomics era has facilitated discovery of new genes predisposing to bone marrow failure (BMF) and hematological malignancy (HM). We report the discovery of ERG as a novel autosomal dominant BMF/HM predisposition gene. ERG is a highly constrained transcription factor critical for definitive hematopoiesis, stem cell function and platelet maintenance. ERG colocalizes with other transcription factors including RUNX1 and GATA2 on promoters/enhancers of genes orchestrating hematopoiesis. We identified a rare heterozygous ERG missense variant in 3 thrombocytopenic individuals from one family and 14 additional ERG variants in unrelated individuals with BMF/HM including 2 de novo cases and 3 truncating variants. Phenotypes associated with pathogenic germline ERG variants included cytopenias (thrombocytopenia, neutropenia, pancytopenia) and HMs (acute myeloid leukemia, myelodysplastic syndrome, acute lymphoblastic leukemia) with onset before 40 years. Twenty ERG variants (19 missense, 1 truncating) including 3 missense population variants were functionally characterized. Thirteen potentially pathogenic ETS domain missense variants displayed loss-of-function characteristics disrupting transcriptional transactivation, DNA-binding and/or nuclear localization. Selected variants overexpressed in mouse fetal liver cells failed to drive myeloid differentiation and cytokine-independent growth in culture, and to promote acute erythroleukemia when transplanted into mice, concordant with these variants being loss-of-function. Four individuals displayed somatic genetic rescue by copy neutral loss of heterozygosity. Identification of predisposing germline ERG variants has clinical implications for patient/family diagnosis, counselling, surveillance, and treatment strategies including selection of bone marrow donors or cell/gene therapy.

DOI: https://doi.org/10.1182/blood.2024024607
J Biol Chem. 2024 Jul 09. pii: S0021-9258(24)02049-0. [Epub ahead of print] 107548

In Fanconi Anemia, impaired accumulation of bone marrow neutrophils during emergency granulopoiesis induces hematopoietic stem cell stress.

Liping Hu, Weiqi Huang, Bin Liu, Elizabeth A Eklund.

  Fanconi Anemia (FA) is an inherited disorder of DNA-repair due to mutation in one of 20+ interrelated genes that repair intra-strand DNA crosslinks and rescue collapsed or stalled replication forks. The most common hematologic abnormality in FA is anemia, but progression to bone marrow failure (BMF), clonal hematopoiesis, or acute myeloid leukemia (AML) may also occur. In prior studies, we found that Fanconi DNA-repair is required for successful emergency granulopoiesis; the process for rapid neutrophil production during the innate immune response. Specifically, Fancc-/- mice did not develop neutrophilia in response to emergency granulopoiesis stimuli, but instead exhibited apoptosis of bone marrow hematopoietic stem cells (HSCs) and differentiating neutrophils. Repeated emergency granulopoiesis challenges induced BMF in most Fancc-/- mice, with AML in survivors. In contrast, we found equivalent neutrophilia during emergency granulopoiesis in Fancc-/-Tp53+/- mice and wild type (WT) mice, without BMF. Since termination of emergency granulopoiesis is triggered by accumulation of bone marrow neutrophils, we hypothesize neutrophilia protects Fancc-/-Tp53+/- bone marrow from the stress of a sustained inflammation that is experienced by Fancc-/- mice. In the current work, we found that blocking neutrophil accumulation during emergency granulopoiesis led to BMF in Fancc-/-Tp53+/- mice, consistent with this hypothesis. Blocking neutrophilia during emergency granulopoiesis in Fancc-/-Tp53+/- mice (but not WT) impaired cell cycle checkpoint activity, also found in Fancc-/- mice. Mechanisms for loss of cell cycle checkpoints during infections challenges may define molecular markers of FA progression, or suggest therapeutic targets for bone marrow protection in this disorder.

Keywords:  DNA damage response; DNA repair; cell cycle; hematopoiesis; inflammasome; innate immunity; neutrophil

DOI:  https://doi.org/10.1016/j.jbc.2024.107548
Nat Commun. 2024 Jul 10. 15(1): 5791

Bioengineered niches that recreate physiological extracellular matrix organisation to support long-term haematopoietic stem cells.

Hannah Donnelly, Ewan Ross, Yinbo Xiao, Rio Hermantara, Aqeel F Taqi, W Sebastian Doherty-Boyd, Jennifer Cassels, Penelope M Tsimbouri, Karen M Dunn, Jodie Hay, Annie Cheng, R M Dominic Meek, Nikhil Jain, Christopher West, Helen Wheadon, Alison M Michie, Bruno Peault, Adam G West, Manuel Salmeron-Sanchez, Matthew J Dalby.

Long-term reconstituting haematopoietic stem cells (LT-HSCs) are used to treat blood disorders via stem cell transplantation. The very low abundance of LT-HSCs and their rapid differentiation during in vitro culture hinders their clinical utility. Previous developments using stromal feeder layers, defined media cocktails, and bioengineering have enabled HSC expansion in culture, but of mostly short-term HSCs and progenitor populations at the expense of naive LT-HSCs. Here, we report the creation of a bioengineered LT-HSC maintenance niche that recreates physiological extracellular matrix organisation, using soft collagen type-I hydrogels to drive nestin expression in perivascular stromal cells (PerSCs). We demonstrate that nestin, which is expressed by HSC-supportive bone marrow stromal cells, is cytoprotective and, via regulation of metabolism, is important for HIF-1α expression in PerSCs. When CD34+ve HSCs were added to the bioengineered niches comprising nestin/HIF-1α expressing PerSCs, LT-HSC numbers were maintained with normal clonal and in vivo reconstitution potential, without media supplementation. We provide proof-of-concept that our bioengineered niches can support the survival of CRISPR edited HSCs. Successful editing of LT-HSCs ex vivo can have potential impact on the treatment of blood disorders.

DOI: https://doi.org/10.1038/s41467-024-50054-0
Cell Rep. 2024 Jul 10. pii: S2211-1247(24)00804-0. [Epub ahead of print]43(7): 114475

Endomucin marks quiescent long-term multi-lineage repopulating hematopoietic stem cells and is essential for their transendothelial migration.

Sophia Engelhard, Montserrat Estruch, Shuyu Qin, Christoph A Engelhard, Francisco G Rodriguez-Gonzalez, Martine Drilsvik, Javier Martin-Gonzalez, Jeng-Wei Lu, David Bryder, Claus Nerlov, Joachim Weischenfeldt, Kristian Reckzeh, Kim Theilgaard-Mönch.

  Endomucin (EMCN) currently represents the only hematopoietic stem cell (HSC) marker expressed by both murine and human HSCs. Here, we report that EMCN+ long-term repopulating HSCs (LT-HSCs; CD150+CD48-LSK) have a higher long-term multi-lineage repopulating capacity compared to EMCN- LT-HSCs. Cell cycle analyses and transcriptional profiling demonstrated that EMCN+ LT-HSCs were more quiescent compared to EMCN- LT-HSCs. Emcn-/- and Emcn+/+ mice displayed comparable steady-state hematopoiesis, as well as frequencies, transcriptional programs, and long-term multi-lineage repopulating capacity of their LT-HSCs. Complementary functional analyses further revealed increased cell cycle entry upon treatment with 5-fluorouracil and reduced granulocyte colony-stimulating factor (GCSF) mobilization of Emcn-/- LT-HSCs, demonstrating that EMCN expression by LT-HSCs associates with quiescence in response to hematopoietic stress and is indispensable for effective LT-HSC mobilization. Transplantation of wild-type bone marrow cells into Emcn-/- or Emcn+/+ recipients demonstrated that EMCN is essential for endothelial cell-dependent maintenance/self-renewal of the LT-HSC pool and sustained blood cell production post-transplant.

Keywords:  CP: Stem cell research; bone marrow niche; cross-species HSC marker; endomucin; endothelial cells; hematopoietic stem cell; mobilization; transplantation

DOI:  https://doi.org/10.1016/j.celrep.2024.114475
Br J Haematol. 2024 Jul 08.

CREST-UK: Real-world effectiveness, safety and outpatient delivery of CPX-351 for first-line treatment of newly diagnosed therapy-related AML and AML with myelodysplasia-related changes in the UK.

Priyanka Mehta, Victoria Campbell, Jamie Maddox, Yngvar Floisand, Anita J M Kalakonda, Jenny O'Nions, Thomas Coats, Sateesh Nagumantry, Katherine Hodgson, Richard Whitmill, Ian Amott, Gillian Flynn, David Taussig, Rui Zhao, Nicholas Cunningham, Montse Roset, Daniel Cuadras, Greg Medalla, Hayley Kuter, Saemi Park, Alex Legg, Anjum B Khan.

  Favourable outcomes with CPX-351 versus conventional 7 + 3 were demonstrated in the pivotal phase III trial in adults aged 60-75 years with newly diagnosed, highrisk/secondary acute myeloid leukaemia (AML). As a complement to the clinical trial and to address important data gaps, the CPX-351 Real-World Effectiveness and SafeTy (CREST-UK; NCT05169307) study evaluated the use of CPX-351 in routine clinical practice in the UK, in 147 patients with newly diagnosed therapy-related AML or AML with myelodysplasia-related changes. Best response of complete remission or complete remission with incomplete platelet or neutrophil recovery was achieved by 53% of evaluable patients. Kaplan-Meier median overall survival (OS) was 12.8 months (95% confidence interval 9.2-15.3). Fifty (34%) patients proceeded to haematopoietic cell transplantation (HCT); median OS landmarked from the HCT date was not reached. There were no new safety concerns with CPX-351 identified in CREST-UK. Patients treated with CPX-351 in the outpatient setting spent an average of 24.4, 16.7, 28.2, and 27.7 fewer days on the ward compared with inpatients during first induction, second induction, first consolidation, and second consolidation, respectively. The results from CREST-UK provide valuable insights into the effectiveness, safety, and outpatient delivery of CPX-351 in routine clinical practice in the UK.

Keywords:  CPX‐351; acute myeloid leukaemia; chemotherapy; clinical observations; real‐world

DOI:  https://doi.org/10.1111/bjh.19622
Cancer Discov. 2024 Jul 08.

Mechanisms of response and tolerance to active RAS inhibition in KRAS-mutant NSCLC.

Haniel A Araujo, Ximo Pechuan-Jorge, Teng Zhou, Minh Truong Do, Xin Hu, Frank R Rojas Alvarez, Maria E Salvatierra, Heladio P Ibarguen, Richard Lee, Rashi Raghulan, Harshit Shah, Mariela A Moreno Ayala, Kevin Chen, Nataliya Tovbis Shifrin, Shuhong Wu, Luisa M Solis Soto, Marcelo V Negrao, Don L Gibbons, David S Hong, Jack A Roth, John V Heymach, Jianjun Zhang, Jingjing Jiang, Mallika Singh, Jacqueline A M Smith, Elsa Quintana, Ferdinandos Skoulidis.

Resistance to inactive state-selective RASG12C inhibitors frequently entails accumulation of RASGTP, rendering effective inhibition of active RAS potentially desirable. Here, we evaluated the anti-tumor activity of the RAS(ON) multi-selective tri-complex inhibitor RMC-7977 and dissected mechanisms of response and tolerance in KRASG12C-mutant NSCLC. Broad-spectrum, reversible RASGTP inhibition with or without concurrent covalent targeting of active RASG12C yielded superior and differentiated antitumor activity across diverse co-mutational KRASG12C-mutant NSCLC mouse models of primary or acquired RASG12C(ON) or (OFF) inhibitor resistance. Interrogation of time-resolved single cell transcriptional responses established an in vivo atlas of multi-modal acute and chronic RAS pathway inhibition in the NSCLC ecosystem and uncovered a regenerative mucinous transcriptional program that supports long-term tumor cell persistence. In patients with advanced KRASG12C-mutant NSCLC, the presence of mucinous histological features portended poor response to sotorasib or adagrasib. Our results have potential implications for personalized medicine and the development of rational RAS inhibitor-anchored therapeutic strategies.

DOI: https://doi.org/10.1158/2159-8290.CD-24-0421
Am J Hematol. 2024 Jul 05.

Evaluating the role of Day 14 bone marrow biopsy and European LeukemiaNet risk classification in predicting overall and relapse-free survival in acute myeloid leukemia.

Metodi Balev, Victor Zibara, Grace Van Hyfte, Jonathan Feld, Marina Kremyanskaya, Michelle Becker, Alla Keyzner, Alan H Shih, Bridget Marcellino, Hannah Levavi, Lewis Silverman, John Mascarenhas, Douglas Tremblay.

Multivariable analysis for overall survival and relapse-free survival demonstrating lack of significant for D14 BM status.

DOI: https://doi.org/10.1002/ajh.27429
Leukemia. 2024 Jul 13.

Altered RNA export by SF3B1 mutants confers sensitivity to nuclear export inhibition.

Sana Chaudhry, Felipe Beckedorff, Shaista Shabbir Jasdanwala, Tulasigeri M Totiger, Maurizio Affer, Abimbola Eunice Lawal, Skye Montoya, Francesco Tamiro, Olivia Tonini, Alexandra Chirino, Andrew Adams, Anya K Sondhi, Stephen Noudali, Alyssa Mauri Cornista, Miah Nicholls, Jumana Afaghani, Paola Robayo, Daniel Bilbao, Stephen D Nimer, Jose Antonio Rodríguez, Shruti Bhatt, Eric Wang, Justin Taylor.

SF3B1 mutations frequently occur in cancer yet lack targeted therapies. Clinical trials of XPO1 inhibitors, selinexor and eltanexor, in high-risk myelodysplastic neoplasms (MDS) revealed responders were enriched with SF3B1 mutations. Given that XPO1 (Exportin-1) is a nuclear exporter responsible for the export of proteins and multiple RNA species, this led to the hypothesis that SF3B1-mutant cells are sensitive to XPO1 inhibition, potentially due to altered splicing. Subsequent RNA sequencing after XPO1 inhibition in SF3B1 wildtype and mutant cells showed increased nuclear retention of RNA transcripts and increased alternative splicing in the SF3B1 mutant cells particularly of genes that impact apoptotic pathways. To identify novel drug combinations that synergize with XPO1 inhibition, a forward genetic screen was performed with eltanexor treatment implicating anti-apoptotic targets BCL2 and BCLXL, which were validated by functional testing in vitro and in vivo. These targets were tested in vivo using Sf3b1K700E conditional knock-in mice, which showed that the combination of eltanexor and venetoclax (BCL2 inhibitor) had a preferential sensitivity for SF3B1 mutant cells without excessive toxicity. In this study, we unveil the mechanisms underlying sensitization to XPO1 inhibition in SF3B1-mutant MDS and preclinically rationalize the combination of eltanexor and venetoclax for high-risk MDS.

DOI: https://doi.org/10.1038/s41375-024-02328-1
Am J Cardiol. 2024 Jul 05. pii: S0002-9149(24)00476-4. [Epub ahead of print]

Symptomatic Heart Failure and Clonal Hematopoiesis-related Mutations in Patients with Acute Myeloid Leukemia.

Yu Kang, Benedicte Lefebvre, Ingrid Marti Pamies, Saar I Gill, Abigail G Doucette, Srinivas Denduluri, Amanda M Smith, Shannon McCurdy, Selina Luger, Joseph Carver, Marielle Scherrer-Crosbie.

  Clonal hematopoiesis of indeterminate potential (CHIP) is a common risk factor for both hematological malignancies and cardiovascular (CV) diseases. The purpose of this study was to investigate the association between CHIP-related mutations and symptomatic heart failure in patients diagnosed with acute myeloid leukemia (AML). A total of 563 patients with newly-diagnosed AML who underwent DNA sequencing of bone marrow before treatment were retrospectively investigated. Cox proportional hazard regression models and Fine and Gray's subdistribution hazard regression models were used to assess the association between CHIP-related mutations and symptomatic heart failure (HF). 79.0% patients had at least 1 CHIP-related mutation; the most frequent mutations were DNMT3A, ASXL1 and TET2. Fifty-one patients (9.1%) developed symptomatic HF. The incidence of symptomatic HF was more frequent in patients with DNMT3A mutations (P<0.01), with a 1-year cumulative incidence of symptomatic HF in patients with DNMT3A mutations of 11.4%, compared to 3.9% in wild-type DNMT3A patients (P<0.01). After adjustment for age and anthracyclines dose, DNMT3A mutations remained independently correlated with HF (HR: 2.32, 95% CI: 1.26-4.29, P=0.01). In conclusion, in patients with AML, the presence of DNMT3A mutations was associated with a 2-fold increased risk for symptomatic HF irrespective of age and anthracyclines use.

Keywords:  Clonal hematopoiesis of indeterminate potential; DNMT3A; Heart failure; acute myeloid leukemia

DOI:  https://doi.org/10.1016/j.amjcard.2024.06.033
Blood. 2024 Jul 10. pii: blood.2024024006. [Epub ahead of print]

New frameworks for hematopoiesis derived from single-cell genomics.

Ksenia Safina, Peter van Galen.

Recent advancements in single-cell genomics have enriched our understanding of hematopoiesis, providing intricate details about hematopoietic stem cell (HSC) biology, differentiation, and lineage commitment. Technological advancements have highlighted extensive heterogeneity of cell populations and continuity of differentiation routes. Nevertheless, intermediate 'attractor' states signify structure in stem and progenitor populations that link state transition dynamics to fate potential. We discuss how innovative model systems quantify lineage bias and how stress accelerates differentiation, thereby reducing fate plasticity compared to native hematopoiesis. We conclude by offering our perspective on the current model of hematopoiesis and discuss how a more precise understanding can translate to strategies that extend healthy hematopoiesis and prevent disease.

DOI: https://doi.org/10.1182/blood.2024024006
Front Oncol. 2024 ;14 1391743

Sorafenib maintenance in FLT3-ITD mutated AML after allogeneic HCT: a real-world, single-center experience.

Elisa Diral, Giulia Furnari, Alessandro Bruno, Raffaella Greco, Daniela Clerici, Sarah Marktel, Francesca Farina, Sara Mastaglio, Luca Vago, Simona Piemontese, Jacopo Peccatori, Consuelo Corti, Massimo Bernardi, Fabio Ciceri, Maria Teresa Lupo-Stanghellini.

  Despite allogeneic hematopoietic stem cell transplant (allo-HCT) and the development of novel FLT3 inhibitors in both induction (midostaurin) and in the relapsed/refractory setting (gilteritinib), FLT3-ITD mutated leukemia (FLT3-ITD+ AML) still represents a challenge for modern hematology. Sorafenib is, to this date, the only inhibitor that demonstrated efficacy in improving both progression-free and overall survival as post-HCT maintenance therapy, even if its use in this setting has not been approved so far by regulatory agencies. The aim of our study was to evaluate the feasibility, safety, and efficacy of sorafenib maintenance in preventing early relapse in FLT3-ITD+ AML after HCT in a single-center experience. We analyzed 26 consecutive patients who received post-HCT 2-year maintenance with sorafenib at our center between 2017 and 2023. The median time from HCT to sorafenib start was 130 days, and the median dosage was 200 mg per day. Two (8%) and three (12%) patients discontinued maintenance due to toxicity and disease relapse, respectively. Eight (31%) patients terminated the 2-year maintenance and stopped sorafenib, while 13 patients are still under treatment. Overall, 21/26 patients (81%) are alive and in stable complete remission as outlined by a 2-year disease-free survival of 83.61%. No major long-term toxicity was reported at the last follow-up. Our real-world experience supports the use of sorafenib as a feasible and effective therapeutic option in post-HCT maintenance for FLT3-ITD+ AML.

Keywords:  FLT3 ITD; acute myeloid leukemia; allogeneic stem cell transplantation; maintenance; sorafenib

DOI:  https://doi.org/10.3389/fonc.2024.1391743
Leuk Lymphoma. 2024 Jul 11. 1-9

Pretransplant desensitization of donor-specific anti-HLA antibodies with plasmapheresis and immunoglobulin produces equivalent outcomes to patients with no donor specific antibodies in haploidentical hematopoietic cell transplant.

Hunter Cassidy Cochran, Michael Joseph Slade, Chang Liu, Feng Gao, Sonia Godbole, Aaron Pruitt, Elisa De Togni, Brenda Grossman, Ramzi Abboud.

  Haploidentical hematopoietic cell transplants (haplo-HCT) with donor-specific anti-HLA antibodies (DSAs) are associated with high rates of primary graft failure and poor overall survival (OS). Limited data exists regarding the effect of desensitization. Our institution began routine desensitization for patients with DSAs in 2014. Adult patients undergoing haplo-HCT at Washington University from 2009-2021 were identified and divided into three cohorts: no DSA, untreated DSA (2009-2014) or treated DSA (2014-2021). Desensitization therapy using plasmapheresis and IVIg was performed. Retrospectively, 304 patients were identified. 14 of 30 patients with DSAs underwent desensitization. By day +2, 57% of patients cleared all DSAs. After multivariable analysis, OS was similar between treated DSA and no DSA (HR: 0.69, p = 0.37). Untreated DSA had significantly lower OS compared to no DSA group (HR 1.80, p = 0.046). Desensitization with a backbone of plasmapheresis and IVIg before haplo-HCT may produce similar outcomes to patients without DSAs.

Keywords:  DSA; Haplo; allogeneic; desensitization; transplant

DOI:  https://doi.org/10.1080/10428194.2024.2376172
Arterioscler Thromb Vasc Biol. 2024 Jul 11.

Decoding Endothelial MPL and JAK2V617F Mutation: Insight Into Cardiovascular Dysfunction in Myeloproliferative Neoplasms.

Haotian Zhang, Nicholas Kafeiti, Kyla Masarik, Sandy Lee, Xiaoxi Yang, Haoyi Zheng, Huichun Zhan.

   BACKGROUND: Patients with JAK2V617F-positive myeloproliferative neoplasms (MPNs) and clonal hematopoiesis of indeterminate potential face a significantly elevated risk of cardiovascular diseases. Endothelial cells carrying the JAK2V617F mutation have been detected in many patients with MPN. In this study, we investigated the molecular basis for the high incidence of cardiovascular complications in patients with MPN.
METHODS: We investigated the impact of endothelial JAK2V617F mutation on cardiovascular disease development using both transgenic murine models and MPN patient-derived induced pluripotent stem cell lines.
RESULTS: Our investigations revealed that JAK2V617F mutant endothelial cells promote cardiovascular diseases under stress, which is associated with endothelial-to-mesenchymal transition and endothelial dysfunction. Importantly, we discovered that inhibiting the endothelial TPO (thrombopoietin) receptor MPL suppressed JAK2V617F-induced endothelial-to-mesenchymal transition and prevented cardiovascular dysfunction caused by mutant endothelial cells. Notably, the endothelial MPL receptor is not essential for the normal physiological regulation of blood cell counts and cardiac function.
CONCLUSIONS: JAK2V617F mutant endothelial cells play a critical role in the development of cardiovascular diseases in JAK2V617F-positive MPNs, and endothelial MPL could be a promising therapeutic target for preventing or ameliorating cardiovascular complications in these patients.

Keywords:  blood cell count; endothelial cells; mice; mutation; neoplasms

DOI:  https://doi.org/10.1161/ATVBAHA.124.321008
Blood Cancer J. 2024 Jul 12. 14(1): 112

Prognostic and therapeutic implications of TP53 expression in chronic myelomonocytic leukemia.

Yu-Hung Wang, Chien-Chin Lin, Kristian Gurashi, Chi-Yuan Yao, Andres Jerez, Hsin-An Hou, Wen-Chien Chou, Hwei-Fang Tien, Kiran Batta, Daniel H Wiseman.

DOI: https://doi.org/10.1038/s41408-024-01087-7
Br J Haematol. 2024 Jul 07.

Multiple small-dose infusions of G-CSF-mobilized haploidentical lymphocytes after autologous haematopoietic stem cell transplantation for acute myeloid leukaemia.

Fei Yang, Quan Ren, Yingling Zu, Ruirui Gui, Zhen Li, Juan Wang, Yanli Zhang, Fengkuan Yu, Baijun Fang, Yuewen Fu, Yongliang Wang, Yanyan Liu, Lina Zhang, Wenli Zuo, Yufu Li, Quande Lin, Huifang Zhao, Ping Wang, Binglei Zhang, Zhenghua Huang, Yongping Song, Jian Zhou.

  This retrospective study analysed 106 acute myeloid leukaemia (AML) patients undergoing autologous haematopoietic stem cell transplantation (ASCT) to assess the impact of multiple small-dose infusions of granulocyte-colony-stimulating factor (G-CSF)-mobilized haploidentical lymphocytes as post-ASCT maintenance therapy. Among them, 50 patients received lymphocyte maintenance therapy, 21 received alternative maintenance therapy, and 35 received no maintenance therapy. Patients receiving lymphocyte maintenance therapy demonstrated significantly higher overall survival (OS) and disease-free survival (DFS) compared to those without maintenance therapy, with 4-year OS and DFS rates notably elevated. While there were no significant differences in recurrence rates among the three groups, lymphocyte maintenance therapy showcased particular benefits for intermediate-risk AML patients, yielding significantly higher OS and DFS rates and lower relapse rates compared to alternative maintenance therapy and no maintenance therapy. The study suggests that multiple small-dose infusions of G-CSF-mobilized haploidentical lymphocytes may offer promising outcomes for AML patients after ASCT, particularly for those classified as intermediate-risk. These findings underscore the potential efficacy of lymphocyte maintenance therapy in reducing disease relapse and improving long-term prognosis in this patient population.

Keywords:  acute myeloid leukaemia; granulocyte colony‐stimulating factor; haematopoietic stem cell transplantation; lymphocytes; relapse prevention

DOI:  https://doi.org/10.1111/bjh.19597
Haematologica. 2024 Jul 11.

The Gordian knot: ruxolitinib or transplants for high-risk myelofibrosis.

Robert Peter Gale, Giovanni Barosi.

Not available.

DOI: https://doi.org/10.3324/haematol.2024.285972
Adv Ther. 2024 Jul 11.

Momelotinib versus Continued Ruxolitinib or Best Available Therapy in JAK Inhibitor-Experienced Patients with Myelofibrosis and Anemia: Subgroup Analysis of SIMPLIFY-2.

Claire N Harrison, Alessandro M Vannucchi, Christian Recher, Francesco Passamonti, Aaron T Gerds, Juan Carlos Hernandez-Boluda, Abdulraheem Yacoub, Shireen Sirhan, Catherine Ellis, Bharat Patel, Bryan Strouse, Uwe Platzbecker.

   INTRODUCTION: Some Janus kinase (JAK) inhibitors such as ruxolitinib and fedratinib do not address and may worsen anemia in patients with myelofibrosis. In these cases, the JAK inhibitor may be continued at a reduced dose in an effort to maintain splenic and symptom control, with supportive therapy and/or red blood cell (RBC) transfusions added to manage anemia. This post hoc descriptive analysis of the phase 3 SIMPLIFY-2 trial evaluated the relative benefits of this approach versus switching to the JAK1/JAK2/activin A receptor type 1 inhibitor momelotinib in patients for whom anemia management is a key consideration.
METHODS: SIMPLIFY-2 was a randomized (2:1), open-label, phase 3 trial of momelotinib versus best available therapy (BAT; 88.5% continued ruxolitinib) in JAK inhibitor-experienced patients with myelofibrosis (n = 156). Patient subgroups (n = 105 each) were defined by either baseline (1) hemoglobin (Hb) of < 100 g/L or (2) non-transfusion independence (not meeting the criteria of no transfusions and no Hb of < 80 g/L for the previous 12 weeks); outcomes have been summarized descriptively.
RESULTS: In both subgroups of interest, week 24 transfusion independence rates were higher with momelotinib versus BAT/ruxolitinib: baseline Hb of < 100 g/L, 22 (33.3%) versus 5 (12.8%); baseline non-transfusion independent, 25 (34.7%) versus 1 (3.0%). Mean Hb levels over time were also generally higher in both subgroups with momelotinib, despite median transfusion rates through week 24 with momelotinib being comparable to or lower than with BAT/ruxolitinib. Spleen and symptom response rates with momelotinib in these subgroups were comparable to the intent-to-treat population, while rates with BAT/ruxolitinib were lower.
CONCLUSION: In patients with moderate-to-severe anemia and/or in need of RBC transfusions, outcomes were improved by switching to momelotinib rather than continuing ruxolitinib and using anemia supportive therapies.
TRIAL REGISTRATION: ClinicalTrials.gov: NCT02101268.

Keywords:  Anemia; Anemia supportive therapy; Erythropoiesis-stimulating agents; Hemoglobin; Momelotinib; Myelofibrosis; Red blood cell transfusions; Ruxolitinib; Transfusion independence

DOI:  https://doi.org/10.1007/s12325-024-02928-4
Nat Commun. 2024 Jul 07. 15(1): 5693

Epigenetic alterations affecting hematopoietic regulatory networks as drivers of mixed myeloid/lymphoid leukemia.

Roger Mulet-Lazaro, Stanley van Herk, Margit Nuetzel, Aniko Sijs-Szabo, Noelia Díaz, Katherine Kelly, Claudia Erpelinck-Verschueren, Lucia Schwarzfischer-Pfeilschifter, Hanna Stanewsky, Ute Ackermann, Dagmar Glatz, Johanna Raithel, Alexander Fischer, Sandra Pohl, Anita Rijneveld, Juan M Vaquerizas, Christian Thiede, Christoph Plass, Bas J Wouters, Ruud Delwel, Michael Rehli, Claudia Gebhard.

Leukemias with ambiguous lineage comprise several loosely defined entities, often without a clear mechanistic basis. Here, we extensively profile the epigenome and transcriptome of a subgroup of such leukemias with CpG Island Methylator Phenotype. These leukemias exhibit comparable hybrid myeloid/lymphoid epigenetic landscapes, yet heterogeneous genetic alterations, suggesting they are defined by their shared epigenetic profile rather than common genetic lesions. Gene expression enrichment reveals similarity with early T-cell precursor acute lymphoblastic leukemia and a lymphoid progenitor cell of origin. In line with this, integration of differential DNA methylation and gene expression shows widespread silencing of myeloid transcription factors. Moreover, binding sites for hematopoietic transcription factors, including CEBPA, SPI1 and LEF1, are uniquely inaccessible in these leukemias. Hypermethylation also results in loss of CTCF binding, accompanied by changes in chromatin interactions involving key transcription factors. In conclusion, epigenetic dysregulation, and not genetic lesions, explains the mixed phenotype of this group of leukemias with ambiguous lineage. The data collected here constitute a useful and comprehensive epigenomic reference for subsequent studies of acute myeloid leukemias, T-cell acute lymphoblastic leukemias and mixed-phenotype leukemias.

DOI: https://doi.org/10.1038/s41467-024-49811-y
Blood. 2024 Jul 08. pii: blood.2023022908. [Epub ahead of print]

CRISPR-based rapid molecular diagnostic tests for fusion-driven leukemias.

Rahul S Vedula, Hannah Q Karp, Jeremy Koob, Felicia Lim, Jacqueline S Garcia, Eric S Winer, Marlise R Luskin, Gabriel Ghiaur, Annette S Kim, Lan W Beppu, Olga Sala-Torra, Jerald P Radich, Jonathan Samuel Gootenberg, Omar Abudayyeh, Feng Zhang, R Coleman Lindsley.

Fusion oncogenes can be cancer-defining molecular alterations that are essential for diagnosis and therapy selection.1,2 Rapid and accessible molecular diagnostics for fusion-driven leukemias such as acute promyelocytic leukemia (APL), Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL), and chronic myeloid leukemia (CML) are unavailable, creating a barrier to timely diagnosis and effective targeted therapy in many healthcare settings, including community hospitals and low-resource environments. We developed CRISPR-based RNA-fusion transcript detection assays using SHERLOCK (Specific High-sensitivity Enzymatic Reporter unLOCKing) for the diagnosis of fusion-driven leukemias. We validated these assays using diagnostic APL and CML patient samples from academic centers and dried blood spots from low-resource environments, demonstrating 100% sensitivity and specificity. We identified assay optimizations to enable the use of these tests outside of tertiary cancer centers and clinical laboratories, enhancing the potential impact of this technology. Rapid point-of-care diagnostics can improve outcomes in cancer patients by expanding access to therapies for highly treatable diseases that would otherwise lead to serious adverse outcomes due to delayed or missed diagnoses.

DOI: https://doi.org/10.1182/blood.2023022908
Commun Biol. 2024 Jul 10. 7(1): 843

Glutathione determines chronic myeloid leukemia vulnerability to an inhibitor of CMPK and TMPK.

Chang-Yu Huang, Yin-Hsuan Chung, Sheng-Yang Wu, Hsin-Yen Wang, Chih-Yu Lin, Tsung-Jung Yang, Jim-Min Fang, Chun-Mei Hu, Zee-Fen Chang.

Bcr-Abl transformation leads to chronic myeloid leukemia (CML). The acquirement of T315I mutation causes tyrosine kinase inhibitors (TKI) resistance. This study develops a compound, JMF4073, inhibiting thymidylate (TMP) and cytidylate (CMP) kinases, aiming for a new therapy against TKI-resistant CML. In vitro and in vivo treatment of JMF4073 eliminates WT-Bcr-Abl-32D CML cells. However, T315I-Bcr-Abl-32D cells are less vulnerable to JMF4073. Evidence is presented that ATF4-mediated upregulation of GSH causes T315I-Bcr-Abl-32D cells to be less sensitive to JMF4073. Reducing GSH biosynthesis generates replication stress in T315I-Bcr-Abl-32D cells that require dTTP/dCTP synthesis for survival, thus enabling JMF4073 susceptibility. It further shows that the levels of ATF4 and GSH in several human CML blast-crisis cell lines are inversely correlated with JMF4073 sensitivity, and the combinatory treatment of JMF4073 with GSH reducing agent leads to synthetic lethality in these CML blast-crisis lines. Altogether, the investigation indicates an alternative option in CML therapy.

DOI: https://doi.org/10.1038/s42003-024-06547-1
Nature. 2024 Jul 10.

Plasmacytoid dendritic cells control homeostasis of megakaryopoiesis.

Florian Gaertner, Hellen Ishikawa-Ankerhold, Susanne Stutte, Wenwen Fu, Jutta Weitz, Anne Dueck, Bhavishya Nelakuditi, Valeria Fumagalli, Dominic van den Heuvel, Larissa Belz, Gulnoza Sobirova, Zhe Zhang, Anna Titova, Alejandro Martinez Navarro, Kami Pekayvaz, Michael Lorenz, Louisa von Baumgarten, Jan Kranich, Tobias Straub, Bastian Popper, Vanessa Zheden, Walter Anton Kaufmann, Chenglong Guo, Guido Piontek, Saskia von Stillfried, Peter Boor, Marco Colonna, Sebastian Clauß, Christian Schulz, Thomas Brocker, Barbara Walzog, Christoph Scheiermann, William C Aird, Claus Nerlov, Konstantin Stark, Tobias Petzold, Stefan Engelhardt, Michael Sixt, Robert Hauschild, Martina Rudelius, Robert A J Oostendorp, Matteo Iannacone, Matthias Heinig, Steffen Massberg.

Platelet homeostasis is essential for vascular integrity and immune defence1,2. Although the process of platelet formation by fragmenting megakaryocytes (MKs; thrombopoiesis) has been extensively studied, the cellular and molecular mechanisms required to constantly replenish the pool of MKs by their progenitor cells (megakaryopoiesis) remains unclear3,4. Here we use intravital imaging to track the cellular dynamics of megakaryopoiesis over days. We identify plasmacytoid dendritic cells (pDCs) as homeostatic sensors that monitor the bone marrow for apoptotic MKs and deliver IFNα to the MK niche triggering local on-demand proliferation and maturation of MK progenitors. This pDC-dependent feedback loop is crucial for MK and platelet homeostasis at steady state and under stress. pDCs are best known for their ability to function as vigilant detectors of viral infection5. We show that virus-induced activation of pDCs interferes with their function as homeostatic sensors of megakaryopoiesis. Consequently, activation of pDCs by SARS-CoV-2 leads to excessive megakaryopoiesis. Together, we identify a pDC-dependent homeostatic circuit that involves innate immune sensing and demand-adapted release of inflammatory mediators to maintain homeostasis of the megakaryocytic lineage.

DOI: https://doi.org/10.1038/s41586-024-07671-y
Blood Sci. 2024 Jul;6(3): e00192

Targeting HMGCS1 restores chemotherapy sensitivity in acute myeloid leukemia.

Cheng Zhou, Jue Li, Xiaofan Sun, Liang Zhao, Huien Zhan, Hui Liang, Peng Fang, Tuo Zhang, Qiongzhi He, Juan Du, Hui Zeng.

  Acute myeloid leukemia (AML) is a common hematological malignancy with overall poor prognosis. Exploring novel targets is urgent and necessary to improve the clinical outcome of relapsed and refractory (RR) AML patients. Through clinical specimens, animal models and cell-level studies, we explored the specific mechanism of 3-hydroxy-3-methylglutaryl coenzyme A synthase 1 (HMGCS1) in AML and the mechanism of targeting HMGCS1 to attenuate cell proliferation, increase chemotherapy sensitivity and improve the occurrence and development of AML. Here, we reveal that HMGCS1 is overexpressed in RR patients and negatively related to overall survival (OS). Knocking out HMGCS1 in AML cells attenuated cell proliferation and increased chemotherapy sensitivity, while stable overexpression of HMGCS1 had the opposite effects. Mechanistically, we identified that knockout of HMGCS1 suppressed mitogen-activated protein kinase (MAPK) pathway activity, while overexpression of HMGCS1 could remarkably enhance the pathway. U0126, a MEK1 inhibitor, offset the effects of HMGCS1 overexpression, indicating that HMGCS1 promotes RR AML through the MAPK pathway. Further, we verified that hymeglusin, a specific inhibitor of HMGCS1, decreases cell growth both in AML cell lines and primary bone marrow cells of AML patients. Furthermore, combination of hymeglusin and the common chemotherapeutic drug cytarabine and adriamycin (ADR) had synergistic toxic effects on AML cells. Our study demonstrates the important role of HMGCS1 in AML, and targeting this protein is promising for the treatment of RR AML.

Keywords:  Chemotherapy sensitivity; HMGCS1; MAPK pathway; Relapsed and refractory AML; Targeted therapy

DOI:  https://doi.org/10.1097/BS9.0000000000000192
Ann Hematol. 2024 Jul 08.

Treatment challenges and outcomes of older patients with acute myeloid leukemia from India.

Suvir Singh, Sharon Lionel, Hasmukh Jain, Akhil Rajendra, Lingaraj Nayak, Sushil Selvarajan, Prasanna Samuel, Rayaz Ahmed, Narendra Aggarwal, Pavitra Ds, Poojitha Byreddy, MJoseph John, Kundan Mishra, Suman Kumar, Mobin Paul, Latha K Abraham, Smita Kayal, Prasanth Ganesan, Chepsy C Philip, Damodar Das, V Sreeraj, Prashant Mehta, Jayachandran Pk, Vineetha Raghavan, Stalin Chowdary Bala, Ram S Bharath, Swaratika Majumdar, Om Prakash, U Barath, Bhausaheb Bagal, Aby Abraham, Rajan Kapoor, Dinesh Bhurani, Manju Sengar, Vikram Mathews.

  Globally, overall survival (OS) of older patients with AML continues to be suboptimal with very little data from India. In a multicenter registry analysis, we evaluated 712 patients with AML older than 55 years. Only 323 (45.3%) underwent further treatment, of which 239 (74%) received HMAs, and 60 (18%) received intensive chemotherapy (IC). CR was documented in 39% of those receiving IC and 42% after HMAs. Overall, 100 (31%) patients died within 60 days of diagnosis, most commonly due to progressive disease (47%) or infections (30%). After a median follow-up of 176 days, 228 (76%) of patients had discontinued treatment. At one year from diagnosis, 211 (65%) patients had died, and the median OS was 186 days (IQR, 137-234). Only 12 (3.7%) patients underwent stem cell transplantation. Survival was significantly lower for those older than 60 years (p < 0.001). Patients who died had a higher median age (p = .027) and baseline WBC counts (p = .006). Our data highlights suboptimal outcomes in older AML patients, which are evident from 55 years of age onwards, making it necessary to evaluate HMA and targeted agent combinations along with novel consolidation strategies to improve survival in this high-risk population.

Keywords:  AML; Cancer; Chemotherapy; Fungal; Leukemia

DOI:  https://doi.org/10.1007/s00277-024-05873-y
Science. 2024 Jul 12. 385(6705): eadl6173

Mutant IDH1 inhibition induces dsDNA sensing to activate tumor immunity.

Meng-Ju Wu, Hiroshi Kondo, Ashwin V Kammula, Lei Shi, Yi Xiao, Sofiene Dhiab, Qin Xu, Chloe J Slater, Omar I Avila, Joshua Merritt, Hiroyuki Kato, Prabhat Kattel, Jonathan Sussman, Ilaria Gritti, Jason Eccleston, Yi Sun, Hyo Min Cho, Kira Olander, Takeshi Katsuda, Diana D Shi, Milan R Savani, Bailey C Smith, James M Cleary, Raul Mostoslavsky, Vindhya Vijay, Yosuke Kitagawa, Hiroaki Wakimoto, Russell W Jenkins, Kathleen B Yates, Jihye Paik, Ania Tassinari, Duygu Hatice Saatcioglu, Adriana E Tron, Wilhelm Haas, Daniel Cahill, Samuel K McBrayer, Robert T Manguso, Nabeel Bardeesy.

Isocitrate dehydrogenase 1 (IDH1) is the most commonly mutated metabolic gene across human cancers. Mutant IDH1 (mIDH1) generates the oncometabolite (R)-2-hydroxyglutarate, disrupting enzymes involved in epigenetics and other processes. A hallmark of IDH1-mutant solid tumors is T cell exclusion, whereas mIDH1 inhibition in preclinical models restores antitumor immunity. Here, we define a cell-autonomous mechanism of mIDH1-driven immune evasion. IDH1-mutant solid tumors show selective hypermethylation and silencing of the cytoplasmic double-stranded DNA (dsDNA) sensor CGAS, compromising innate immune signaling. mIDH1 inhibition restores DNA demethylation, derepressing CGAS and transposable element (TE) subclasses. dsDNA produced by TE-reverse transcriptase (TE-RT) activates cGAS, triggering viral mimicry and stimulating antitumor immunity. In summary, we demonstrate that mIDH1 epigenetically suppresses innate immunity and link endogenous RT activity to the mechanism of action of a US Food and Drug Administration-approved oncology drug.

DOI: https://doi.org/10.1126/science.adl6173
Blood Adv. 2024 Jul 10. pii: bloodadvances.2024012968. [Epub ahead of print]

Phase II study of a longitudinal rehabilitation program for allogeneic blood and marrow transplantation patients.

Samantha Tam, Shabbir Mh Alibhai, Dima El Hassanieh, Rajat Kumar, Jonas I Mattsson, Eshetu G Atenafu, Lisa Avery, Lori J Bernstein, Eugene Chang, David Michael Langelier, Paty Lopez, Jennifer Michelle Jones.

Allogeneic blood and marrow transplantation (alloBMT) is a curative treatment for blood cancers associated with various treatment-related adverse events and morbidities for which rehabilitation programs are currently limited. A Phase II randomized controlled trial (RCT) was conducted to assess the feasibility, acceptability, and impact of CaRE-4-alloBMT: a longitudinal multidimensional cancer rehabilitation program for patients undergoing alloBMT. Primary outcomes included the feasibility and acceptability of the intervention and methods. Feasibility was assessed through recruitment, retention, and adherence rates. Acceptability was assessed through qualitative interviews. Secondary clinical outcomes were collected through questionnaires and physiological assessments at four time points. A total of 80 participants were recruited and randomized. Recruitment (72%) and retention (70%) rates, along with qualitative findings, support the feasibility of the intervention. Adherence was suboptimal, most notably educational module completion (22.7%). Treatment effect sizes of 0.70, 95% CI [0.20, 1.21] (30-second sit-to-stand test), and 0.46, 95% CI [-0.17, 1.09] (SF-36) were observed in favour of the intervention. Results appear promising; however, findings are limited by missing data from attrition. Modifications will be required to refine the program and inform a Phase III RCT. (NCT04966156).

DOI: https://doi.org/10.1182/bloodadvances.2024012968
Eur J Haematol. 2024 Jul 09.

Outcomes with low dose anti-thymocyte globulin based graft versus host disease prophylaxis after mismatched unrelated donor allogeneic hematopoietic cell transplantation.

Hafsah Chalchal, Vinita Dhir, Ashish Masurekar, Harold Atkins, Christopher Bredeson, Michael Kennah, Natasha Kekre, David Allan, Ram Vasudevan Nampoothiri.

   BACKGROUND: Anti-thymocyte globulin (ATG) based graft versus host disease (GVHD) prophylaxis is widely used for mismatched unrelated donor allogeneic hematopoietic cell transplantation (HCT) although optimal dose remains unclear. Although recent literature suggested improved outcomes with PTCy-based regimens when compared to ATG-based regimens these studies used doses of ATG ≥5 mg/kg. Thus, we analyzed outcomes of HLA 9/10 MMUD allogeneic HCTs using lower-dose ATG-based regimens at our center.
METHODS: We retrospectively analyzed outcomes of HLA 9/10 MMUD allogeneic HCTs using lower dose ATG-based regimens for all adults undergoing allogeneic HCT at The Ottawa Hospital from 2015 to 2022. Data regarding demographics, conditioning regimen, dose of ATG, rates of GVHD, duration of remission, and survival, were collected and analyzed.
RESULTS: Seventy-seven (n = 77) patients (males 62.3%; median age 50 years) underwent allogeneic HCT from MMUD. Majority(81%; n = 63) received 2.5 mg/kg of rabbit ATG and remaining 18.2% (n = 14) received 4.5 mg/kg. Grade II-IV acute GVHD occurred in 24.7% (n = 19) while any chronic GVHD occurred in 32.5% (n = 25) patients. After a median follow-up of 21 months, relapse occurred in 28.6% of patients. Two-year OS, GRFS, CIR, and NRM were 60.6%, 45.3%, 16.9%, and 18.2% respectively. Dose of ATG (2.5 mg/kg vs. 4.5 mg/kg) was not associated with outcomes in either univariate or multivariate analyses.
CONCLUSIONS: When compared to published studies using ATG doses ≥5 mg/kg, GVHD prophylaxis using lower dose ATG may potentially lead to improved outcomes in patients undergoing MMUD allogeneic HCT. Further studies are needed to directly compare lower dose ATG to PTCy-based regimens to determine ideal GVHD prophylaxis for these patients.

Keywords:  GVHD prophylaxis; allogeneic stem cell transplantation; low dose anti‐thymocyte globulin; mismatched unrelated donor

DOI:  https://doi.org/10.1111/ejh.14274
Blood Adv. 2024 Jul 11. pii: bloodadvances.2023011894. [Epub ahead of print]

In Utero Hematopoietic Stem Cell Transplantation for Fanconi Anemia.

Leah Swartzrock, Carla Dib, Morgane Denis, Hana Willner, Katie Ho, Ethan Haslett, Jian Han, Wenjing Pan, Miranda Byrne-Steele, Brittany Brown, Mark R Krampf, Anna Girsen, Yair J Blumenfeld, Yasser Y El-Sayed, Maria Grazia Grazia Roncarolo, Tippi C MacKenzie, Agnieszka D Czechowicz.

DOI: https://doi.org/10.1182/bloodadvances.2023011894
JCO Precis Oncol. 2024 Jun;8 e2400143

Clonal Hematopoiesis in Patients With Neuroendocrine Tumor Treated With Lutetium-177 and the Risk of Thrombocytopenia: A Prospective Study.

Yael Kusne, Terra Lasho, Christy Finke, Zaid Elsabbagh, Shaylene McCue, Timothy Hobday, Jason Starr, Tanios Bekaii-Saab, Thorvardur R Halfdanarson, Mrinal M Patnaik, Fang-Shu Ou, Mohamad Bassam Sonbol.

PURPOSE: Thrombocytopenia is a relatively common dose-limiting toxicity during peptide receptor radionuclide therapy (PRRT) in patients with NET. Although uncommon, some patients develop persistent cytopenia and eventually therapy-related myeloid neoplasm (t-MN), which has a dismal prognosis. As the indications for PRRT are expanding, it is important to investigate factors that may predict cytopenias during/after PRRT. We prospectively evaluated the prevalence of clonal hematopoiesis (CH) and cytopenia in patients with NET undergoing PRRT.
MATERIALS AND METHODS: Patients with metastatic NET with plan to receive four cycles of lutetium-177 were enrolled. CH was evaluated before PRRT using a panel of 220 genes with a targeted depth of ≥1,000×. Patients were followed during PRRT and every 3 months thereafter.
RESULTS: Of 37 patients enrolled, the median age was 68 years and 51.4% were male. Previous treatment exposures included alkylating agents in 30%, platinum agents in 8%, and external radiation in 13%. CH was detected in 35.1% using a variant allele frequency (VAF) cutoff of ≥2% and 45.9% with a VAF of ≥1%. The most common mutations were in age-related genes (DNMT3A, TET2). CH was not associated with anemia or neutropenia; however, it was associated with lower platelet count at baseline and more time spent in a thrombocytopenic state during/after PRRT. Five patients had bone marrow biopsies (BMBs) because of sustained hematologic dysfunction post-PRRT, and of those, diagnoses included clonal cytopenia of undetermined significance (CCUS) in three and idiopathic cytopenia of undetermined significance (ICUS) in two.
CONCLUSION: CH is present in 35.1% of patients with NET and is associated with thrombocytopenia risk during PRRT. Future studies with long-term follow-up will delineate whether CH might be a predictor for higher risk of t-MN after PRRT.

DOI: https://doi.org/10.1200/PO.24.00143
Leukemia. 2024 Jul 11.

The RNA helicases DDX19A/B modulate selinexor sensitivity by regulating MCL1 mRNA nuclear export in leukemia cells.

Tatsuya Terasaki, Yuichiro Semba, Kensuke Sasaki, Hiroshi Imanaga, Kiyoko Setoguchi, Takuji Yamauchi, Shigeki Hirabayashi, Fumihiko Nakao, Koshi Akahane, Takeshi Inukai, Takaomi Sanda, Koichi Akashi, Takahiro Maeda.

Selinexor, a first-in-class exportin1 (XPO1) inhibitor, is an attractive anti-tumor agent because of its unique mechanisms of action; however, its dose-dependent toxicity and lack of biomarkers preclude its wide use in clinical applications. To identify key molecules/pathways regulating selinexor sensitivity, we performed genome-wide CRISPR/Cas9 dropout screens using two B-ALL lines. We identified, for the first time, that paralogous DDX19A and DDX19B RNA helicases modulate selinexor sensitivity by regulating MCL1 mRNA nuclear export. While single depletion of either DDX19A or DDX19B barely altered MCL1 protein levels, depletion of both significantly attenuated MCL1 mRNA nuclear export, reducing MCL1 protein levels. Importantly, combining selinexor treatment with depletion of either DDX19A or DDX19B markedly induced intrinsic apoptosis of leukemia cells, an effect rescued by MCL1 overexpression. Analysis of Depmap datasets indicated that a subset of T-ALL lines expresses minimal DDX19B mRNA levels. Moreover, we found that either selinexor treatment or DDX19A depletion effectively induced apoptosis of T-ALL lines expressing low DDX19B levels. We conclude that XPO1 and DDX19A/B coordinately regulate cellular MCL1 levels and propose that DDX19A/B could serve as biomarkers for selinexor treatment. Moreover, pharmacological targeting of DDX19 paralogs may represent a potential strategy to induce intrinsic apoptosis in leukemia cells.

DOI: https://doi.org/10.1038/s41375-024-02343-2
Nat Commun. 2024 Jul 11. 15(1): 5822

PARG is essential for Polθ-mediated DNA end-joining by removing repressive poly-ADP-ribose marks.

Umeshkumar Vekariya, Leonid Minakhin, Gurushankar Chandramouly, Mrityunjay Tyagi, Tatiana Kent, Katherine Sullivan-Reed, Jessica Atkins, Douglas Ralph, Margaret Nieborowska-Skorska, Anna-Mariya Kukuyan, Hsin-Yao Tang, Richard T Pomerantz, Tomasz Skorski.

DNA polymerase theta (Polθ)-mediated end-joining (TMEJ) repairs DNA double-strand breaks and confers resistance to genotoxic agents. How Polθ is regulated at the molecular level to exert TMEJ remains poorly characterized. We find that Polθ interacts with and is PARylated by PARP1 in a HPF1-independent manner. PARP1 recruits Polθ to the vicinity of DNA damage via PARylation dependent liquid demixing, however, PARylated Polθ cannot perform TMEJ due to its inability to bind DNA. PARG-mediated de-PARylation of Polθ reactivates its DNA binding and end-joining activities. Consistent with this, PARG is essential for TMEJ and the temporal recruitment of PARG to DNA damage corresponds with TMEJ activation and dissipation of PARP1 and PAR. In conclusion, we show a two-step spatiotemporal mechanism of TMEJ regulation. First, PARP1 PARylates Polθ and facilitates its recruitment to DNA damage sites in an inactivated state. PARG subsequently activates TMEJ by removing repressive PAR marks on Polθ.

DOI: https://doi.org/10.1038/s41467-024-50158-7
Nat Commun. 2024 Jul 08. 15(1): 5706

tRNA m1A modification regulate HSC maintenance and self-renewal via mTORC1 signaling.

Hongna Zuo, Aiwei Wu, Mingwei Wang, Liquan Hong, Hu Wang.

Haematopoietic stem cells (HSCs) possess unique physiological adaptations to sustain blood cell production and cope with stress responses throughout life. To maintain these adaptations, HSCs rely on maintaining a tightly controlled protein translation rate. However, the mechanism of how HSCs regulate protein translation remains to be fully elucidated. In this study, we investigate the role of transfer RNA (tRNA) m1A58 'writer' proteins TRMT6 and TRMT61A in regulating HSCs function. Trmt6 deletion promoted HSC proliferation through aberrant activation of mTORC1 signaling. TRMT6-deficient HSCs exhibited an impaired self-renewal ability in competitive transplantation assay. Mechanistically, single cell RNA-seq analysis reveals that the mTORC1 signaling pathway is highly upregulated in HSC-enriched cell populations after Trmt6 deletion. m1A-tRNA-seq and Western blot analysis suggest that TRMT6 promotes methylation modification of specific tRNA and expression of TSC1, fine-tuning mTORC1 signaling levels. Furthermore, Pharmacological inhibition of the mTORC1 pathway rescued functional defect in TRMT6-deficient HSCs. To our knowledge, this study is the first to elucidate a mechanism by which TRMT6-TRMT61A complex-mediated tRNA-m1A58 modification regulates HSC homeostasis.

DOI: https://doi.org/10.1038/s41467-024-50110-9
Heliyon. 2024 Jun 30. 10(12): e32729

Structural screening and molecular simulation identify potential ligands against the K700E hot spot variant and functional pockets of SF3B1 to modulate splicing in myelodysplastic syndrome.

Rolando García, Murat Atis, Andrew Cox, Prasad Koduru.

Myelodysplastic syndrome (MDS), a blood disorder with ineffective hematopoiesis and risk of transformation to acute myeloid leukemia, is characterized by recurring cytogenetic and molecular alterations. By chromosome analysis, approximately 60% of patients, carry chromosome 5 and 7 alterations, trisomy of chromosome 8 and may also present with increasingly complex karyotypes, especially in higher grade MDS (MDS with refractory anemia and increased blasts type 1 and 2). Moreover, somatic pathogenic variants in genes associated with aberrant mRNA splicing are frequently mutated with SF3B1 the most frequently mutated. In the setting of SF3B1, the K700E hot-spot mutation is present in approximately 50% of cases. Since recent studies have highlighted modulation of functional dynamics in SF3B1 by mutant splicing factors, the objective of the study was to identify potential small molecule modulators against the frequently mutated RNA splicing factor SF3B1(K700E) and functional allosteric sites by using a molecular structure-based approach and a molecular dynamic simulation. To identify potential SF3B1 modulators, we collected a series of chemical compounds from the Zinc and Enamine database. An initial screen followed by further molecular analysis and simulation using the Schrödinger suite was performed. Parameters used to monitor the stability and binding of the protein-ligand complex included: RMSF, protein-ligand contacts, electrostatic, Van Der Waals forces and binding energies (MMGBSA). A 100-nanosecond simulation showed strong binding between selected compounds and key amino acid residues, including the mutation hot-spot K700E and functional allosteric amino acid residue R630. Ligand binding energies between compounds and key amino acid residues ranged from -50.67 to -58.04 kcal/mol. In brief, small molecule modulators show strong binding to SF3B1 suggesting these compounds may be used against cells harboring the K700E variant or to modulate splicing by targeting functional allosteric sites.

DOI: https://doi.org/10.1016/j.heliyon.2024.e32729