bims-tremyl 2023-06-25 papers

bims-tremyl

Biomed News

on Therapy resistance biology in myeloid leukemia

Issue of 2023–06–25
38 papers selected by
Paolo Gallipoli, Barts Cancer Institute, Queen Mary University of London

Epichaperome inhibition targets TP53-mutant AML and AML stem/progenitor cells.
Phase 1/2 Study of Sorafenib Added to Cladribine, High-Dose Cytarabine, G-CSF, and Mitoxantrone in Untreated AML.
Mdm2/p53 levels in bone marrow mesenchymal stromal cells are essential for maintaining the hematopoietic niche in response to DNA damage.
Genomic landscape of TP53-mutated myeloid malignancies.
Evolving trends and outcomes in older patients with acute myeloid leukemia including allogeneic stem cell transplantation.
Age and sex associate with outcome in older AML and high risk MDS patients treated with 10-day decitabine.
Genotoxic aldehyde stress prematurely ages hematopoietic stem cells in a p53-driven manner.
MCL1 regulates AML cells metabolism via direct interaction with HK2. Metabolic signature at onset predicts overall survival in AMLs' patients.
Real-world effectiveness of intensive chemotherapy with 7&3 versus venetoclax and hypomethylating agent in acute myeloid leukemia.
Cell-cell interactome of the hematopoietic niche and its changes in acute myeloid leukemia.
Luspatercept use for lower risk myelodysplastic syndromes: Active but not enough.
Exclusion of persistent mutations in splicing factor genes and isocitrate dehydrogenase 2 improves the prognostic power of molecular measurable residual disease assessment in acute myeloid leukemia.
Measurable residual disease in patients undergoing allogeneic transplant for acute myeloid leukemia.
A Metabolically Optimized, Noncytotoxic Low-Dose Weekly Decitabine/Venetoclax in MDS and AML.
DNA damage primes hematopoietic stem cells for direct megakaryopoiesis.
Efficacy and toxicity of midostaurin with idarubicin and cytarabine induction in FLT3-mutated acute myeloid leukemia.
Community detection in empirical kinase networks identifies new potential members of signalling pathways.
The transcriptomic landscape of normal and ineffective erythropoiesis at single-cell resolution.
Can Measurable Residual Disease (MRD) assessment be reliably used to defer allogeneic stem cell transplant in patients with intermediate-risk acute myeloid leukemia?
BCR-ABL promotes hematopoietic stem and progenitor cell formation in embryonic stem cells.
Getting to the core of ADAR2 activity in AML.
Advanced Systemic Mastocytosis with associated haematological neoplasm: Treatment with avapritinib can facilitate successful bridge to allogeneic haematopoietic cell transplant.
Preclinical Validation of an Advanced Therapy Medicinal Product Based on Cytotoxic T Lymphocytes Specific for Mutated Nucleophosmin (NPM1mut) for the Treatment of NPM1mut-Acute Myeloid Leukemia.
Comparing the value of mono- versus coculture for high-throughput compound screening in hematological malignancies.
NUP98 and RAE1 sustain progenitor function through HDAC-dependent chromatin targeting to escape from nucleolar localization.
ETV2 primes hematoendothelial gene enhancers prior to hematoendothelial fate commitment.
Tacrolimus/methotrexate vs tacrolimus/reduced-dose methotrexate/mycophenolate for graft-vs-host disease prevention.
Ruxolitinib improves hematopoietic regeneration by restoring mesenchymal stromal cell function in acute graft-versus-host disease.
Genomic breakpoint specific monitoring of measurable residual disease in pediatric non-standard risk acute myeloid leukemia.
Comparison of outcomes for patients with acute myeloid leukemia undergoing haploidentical stem cell transplantation in first and second complete remission.
Activation of the cGAS/STING axis in genome-damaged hematopoietic cells does not impact blood cell formation or leukemogenesis.
The genesis of human hematopoietic stem cells.
Allogeneic haematopoietic stem cell transplantation for myelofibrosis: prognostic indicators and the role of JAK2V617F measurable-residual disease monitoring by droplet-digital polymerase chain reaction.
Effect of age and treatment on predictive value of measurable residual disease: implications for clinical management of adult patients with acute myeloid leukemia.
Busulfan Plus Fludarabine Compared With Busulfan Plus Cyclophosphamide for AML Undergoing HLA-Haploidentical Hematopoietic Cell Transplantation: A Multicenter Randomized Phase III Trial.
Transcriptomic classes of BCR-ABL1 lymphoblastic leukemia.
Clonal Hematopoiesis: Updates and Implications at the Solid Tumor-Immune Interface.
Intracranial bleeding in acute promyelocytic leukemia treated with arsenic trioxide based regimens is associated with induction mortality but not with relapse.

Blood. 2023 06 20. pii: blood.2022019047. [Epub ahead of print]

Epichaperome inhibition targets TP53-mutant AML and AML stem/progenitor cells.

Bing Z Carter, Po Yee Mak, Muharrem Muftuoglu, Wenjing Tao, Ke Baozhen, Jingqi Pei, Andrea D Bedoy, Lauren B Ostermann, Yuki Nishida, Sevinj Isqandarova, Mary Sobieski, Nghi Nguyen, Reid T Powell, Margarita Martinez-Moczyemba, Clifford Stephan, Mahesh Basyal, Naveen Pemmaraju, Steffen Boettcher, Benjamin L Ebert, Elizabeth J Shpall, Barbara P Wallner, Robert Morgan, Georgios I Karras, Ute Moll, Michael Andreeff.

TP53-mutant acute myeloid leukemia (AML) remains the ultimate therapeutic challenge. Epichaperomes, formed in malignant cells, consist of heat shock protein 90 (HSP90) and associated proteins that support the maturation, activity, and stability of oncogenic kinases and transcription factors including mutant p53. High-throughput drug screening identified HSP90 inhibitors as top hits in isogenic TP53-wild type (WT) and -mutant AML cells. We detected epichaperomes in AML cells and stem/progenitor cells with TP53 mutations but not in normal bone marrow (BM) cells. Hence, we investigated the therapeutic potential of specifically targeting epichaperomes with PU-H71 in TP53-mutant AML based on its preferred binding to HSP90 within epichaperomes. PU-H71 effectively suppressed cell intrinsic stress responses and killed AML cells, primarily by inducing apoptosis; targeted TP53-mutant stem/progenitor cells; prolonged survival of TP53 mutant AML xenograft and PDX models but had minimal effects on normal human BM CD34+ cells or on murine hematopoiesis. PU-H71 decreased MCL-1 and multiple signal proteins, increased pro-apoptotic BIM levels, and synergized with BCL-2 inhibitor venetoclax in TP53-mutant AML. Notably, PU-H71 effectively killed TP53-WT and -mutant cells in isogenic TP53-WT/TP53-R248W Molm13 cell mixtures, whereas MDM2 or BCL-2 inhibition only reduced TP53-WT but favored the outgrowth of TP53-mutant cells. Venetoclax enhanced PU-H71's killing of both TP53-WT and -mutant cells in a xenograft model. Our data suggest that epichaperome function is essential for TP53-mutant AML growth and survival and that its inhibition targets mutant AML and stem/progenitor cells, enhances venetoclax activity, and prevents the outgrowth of venetoclax-resistant TP53-mutant AML clones. These concepts warrant clinical evaluation.

DOI: https://doi.org/10.1182/blood.2022019047
Blood Adv. 2023 Jun 20. pii: bloodadvances.2023010392. [Epub ahead of print]

Phase 1/2 Study of Sorafenib Added to Cladribine, High-Dose Cytarabine, G-CSF, and Mitoxantrone in Untreated AML.

Anna B Halpern, Eduardo Rodríguez-Arbolí, Megan Othus, Kelsey-Leigh A Garcia, Mary-Elizabeth M Percival, Ryan D Cassaday, Vivian G Oehler, Pamela S Becker, Jacob Appelbaum, Janis L Abkowitz, Johnnie J Orozco, Sioban B Keel, Paul Hendrie, Bart L Scott, Cristina Maria M Ghiuzeli, Elihu Estey, Roland B Walter.

The multikinase inhibitor sorafenib improves event-free survival (EFS) when used with 7+3 in younger adults with newly diagnosed acute myeloid leukemia (AML) irrespective of FLT3 mutation status. Here, we evaluated adding sorafenib to CLAG-M (cladribine, high-dose cytarabine, G-CSF, mitoxantrone) in a phase 1/2 trial of 81 adults age ≤60 years with newly diagnosed AML or high-grade myeloid neoplasm. Forty-six patients were treated in phase 1 with escalating doses of sorafenib and mitoxantrone. No maximum tolerated dose was reached, and a regimen including mitoxantrone at 18 mg/m2/day and sorafenib 400 mg twice daily was declared the recommended phase 2 dose (RP2D). Among 41 patients treated at the RP2D, a measurable residual disease-negative complete remission (MRDneg CR) rate of 83% (95% confidence interval [CI]: 68-93%) was obtained. Four-week mortality was 2% (95% CI: 0-13%). One-year overall survival (OS) and EFS were 80% (95% CI: 69-94%) and 76% (95% CI 64-90%), without significant difference in MRDneg CR rates, OS, or EFS between patients with or without FLT3-mutated disease. Comparing outcomes with CLAG-M/sorafenib to a matched cohort of 76 patients treated with CLAG-M alone, multivariable adjusted survival estimates were improved for the 41 patients receiving CLAG-M/sorafenib at RP2D (OS: hazard ratio [HR]=0.24 [95% CI: 0.07-0.82], P=0.023; EFS: HR=0.16 [95% CI: 0.05-0.53], P=0.003). Statistically significant benefit was limited to patients with intermediate-risk disease (in univariate analysis, P=0.01 for OS and P=0.02 for EFS). These data suggest CLAG-M/sorafenib is safe and improves OS and EFS relative to CLAG-M alone, with benefit primarily for patients with intermediate-risk disease. The trial is registered on clinicialtrials.gov as NCT02728050.

DOI: https://doi.org/10.1182/bloodadvances.2023010392
Cell Death Dis. 2023 Jun 23. 14(6): 371

Mdm2/p53 levels in bone marrow mesenchymal stromal cells are essential for maintaining the hematopoietic niche in response to DNA damage.

Rasoul Pourebrahim, Rafael Heinz Montoya, Zoe Alaniz, Lauren Ostermann, Patrick P Lin, Bin Liu, Edward Ayoub, Jared K Burks, Michael Andreeff.

Mesenchymal stromal cells (MSCs) are a key component of the bone marrow (BM) niche, providing essential support required for the maintenance of hematopoietic stem cells. To advance our understanding of physiological functions of p53 and Mdm2 in BM-MSCs, we developed traceable conditional mouse models targeting Mdm2 and/or Trp53 in vivo. We demonstrate that Mdm2 is essential for the emergence, maintenance, and hematopoietic support of BM-MSCs. Mdm2 haploinsufficiency in BM-MSCs resulted in genotoxic stress-associated thrombocytopenia, suggesting a functional role for Mdm2 in hematopoiesis. In a syngeneic mouse model of acute myeloid leukemia (AML), Trp53 deletion in BM-MSCs improved survival, and protected BM against hematopoietic toxicity from a murine Mdm2i, DS-5272. The transcriptional changes were associated with dysregulation of glycolysis, gluconeogenesis, and Hif-1α in BM-MSCs. Our results reveal a physiologic function of Mdm2 in BM-MSC, identify a previously unknown role of p53 pathway in BM-MSC-mediated support in AML and expand our understanding of the mechanism of hematopoietic toxicity of MDM2is.

DOI: https://doi.org/10.1038/s41419-023-05844-7
Blood Adv. 2023 Jun 20. pii: bloodadvances.2023010156. [Epub ahead of print]

Genomic landscape of TP53-mutated myeloid malignancies.

Haley J Abel, Karolyn A Oetjen, Christopher A Miller, Sai M Ramakrishnan, Ryan B Day, Nichole M Helton, Catrina C Fronick, Robert S Fulton, Sharon E Heath, Stefan P Tarnawsky, Sridhar Nonavinkere Srivatsan, Eric J Duncavage, Molly C Schroeder, Jacqueline E Payton, David H Spencer, Matthew J Walter, Peter Westervelt, John F DiPersio, Timothy J Ley, Daniel C Link.

TP53-mutated myeloid malignancies are associated with complex cytogenetics and extensive structural variants, which complicates detailed genomic analysis by conventional clinical techniques. We performed whole genome sequencing (WGS) of 42 AML/MDS cases with paired normal tissue to better characterize the genomic landscape of TP53-mutated AML/MDS. WGS accurately determines TP53 allele status, a key prognostic factor, resulting in the reclassification of 12% of cases from mono-allelic to multi-hit. Although aneuploidy and chromothripsis are shared with most TP53-mutated cancers, the specific chromosome abnormalities are distinct to each cancer type, suggesting a dependence on the tissue of origin. ETV6 expression is reduced in nearly all cases of TP53-mutated AML/MDS, either through gene deletion or presumed epigenetic silencing. Within the AML cohort, mutations of NF1 are highly enriched, with deletions of one copy of NF1 present in 45% of cases and biallelic mutations in 17%. Telomere content is increased in TP53-mutated AMLs compared to other AML subtypes, and abnormal telomeric sequences were detected in the interstitial regions of chromosomes. These data highlight the unique features of TP53-mutated myeloid malignancies, including the high frequency of chromothripsis and structural variation, the frequent involvement of unique genes (including NF1 and ETV6) as cooperating events, and evidence for altered telomere maintenance.

DOI: https://doi.org/10.1182/bloodadvances.2023010156
Am J Hematol. 2023 Jun 19.

Evolving trends and outcomes in older patients with acute myeloid leukemia including allogeneic stem cell transplantation.

Alexandre Bazinet, Hagop Kantarjian, Naszrin Arani, Uday Popat, Alex Bataller, Koji Sasaki, Courtney D DiNardo, Naval Daver, Musa Yilmaz, Hussein A Abbas, Nicholas J Short, Ghayas Issa, Elias Jabbour, Sherry A Pierce, Julianne Chen, Ricky Garcia, Marina Konopleva, Guillermo Garcia-Manero, Amin Alousi, Elizabeth J Shpall, Richard E Champlin, Gautam Borthakur, Farhad Ravandi, Tapan Kadia.

Outcomes in older patients with acute myeloid leukemia (AML) have historically been poor. Given advances in low-intensity therapy (LIT) and stem cell transplantation (SCT), we performed a retrospective single-center study to evaluate the contemporary outcomes of this population. We reviewed all patients ≥60 years with newly diagnosed AML between 2012 and 2021 and analyzed treatment and SCT-related trends and outcomes. We identified 1073 patients with a median age of 71 years. Adverse clinical and cytomolecular findings were frequent within this cohort. In total, 16% of patients were treated with intensive chemotherapy, 51% with LIT alone, and 32% with LIT plus venetoclax. The composite complete remission rate with LIT plus venetoclax was 72%, which was higher than with LIT alone (48%, p < .0001) and comparable to intensive chemotherapy (74%, p = .6). The median overall survival (OS) with intensive chemotherapy, LIT, and LIT plus venetoclax was 20.1, 8.9, and 12.1 months, respectively. 18% of patients received SCT. SCT rates were 37%, 10%, and 22% in patients treated with intensive chemotherapy, LIT, and LIT plus venetoclax, respectively. The 2-year OS, relapse-free survival (RFS), cumulative incidence (CI) of relapse, and CI of treatment-related mortality with frontline SCT (n = 139) were 59%, 52%, 27%, and 22%, respectively. By landmark analysis, patients undergoing frontline SCT had superior OS (median 39.6 vs. 21.4 months, p < .0001) and RFS (30.9 vs. 12.1 months, p < .0001) compared with responding patients who did not. Outcomes in older patients with AML are improving with more effective LIT. Measures should be pursued to increase access to SCT in older patients.

DOI: https://doi.org/10.1002/ajh.26997
Blood Cancer J. 2023 Jun 19. 13(1): 93

Age and sex associate with outcome in older AML and high risk MDS patients treated with 10-day decitabine.

Dutch-Belgian Hemato-Oncology Cooperative Group (HOVON)

Treatment choice according to the individual conditions remains challenging, particularly in older patients with acute myeloid leukemia (AML) and high risk myelodysplastic syndrome (MDS). The impact of performance status, comorbidities, and physical functioning on survival is not well defined for patients treated with hypomethylating agents. Here we describe the impact of performance status (14% ECOG performance status 2), comorbidity (40% HCT-comorbidity index ≥ 2), and physical functioning (41% short physical performance battery < 9 and 17% ADL index < 6) on overall survival (OS) in 115 older patients (age ≥ 66 years) treated on a clinical trial with a 10-day decitabine schedule. None of the patient-related variables showed a significant association with OS. Multivariable analysis revealed that age > 76 years was significantly associated with reduced OS (HR 1.58; p = 0.043) and female sex was associated with superior OS (HR 0.62; p = 0.06). We further compared the genetic profiles of these subgroups. This revealed comparable mutational profiles in patients younger and older than 76 years, but, interestingly, revealed significantly more prevalent mutated ASXL1, STAG2, and U2AF1 in male compared to female patients. In this cohort of older patients treated with decitabine age and sex, but not comorbidities, physical functioning or cytogenetic risk were associated with overall survival.

DOI: https://doi.org/10.1038/s41408-023-00850-6
Mol Cell. 2023 Jun 15. pii: S1097-2765(23)00419-7. [Epub ahead of print]

Genotoxic aldehyde stress prematurely ages hematopoietic stem cells in a p53-driven manner.

Meng Wang, Laura T L Brandt, Xiaonan Wang, Holly Russell, Emily Mitchell, Ashley N Kamimae-Lanning, Jill M Brown, Felix A Dingler, Juan I Garaycoechea, Tomoya Isobe, Sarah J Kinston, Muxin Gu, George S Vassiliou, Nicola K Wilson, Berthold Göttgens, Ketan J Patel.

  Aged hematopoietic stem cells (HSCs) display diminished self-renewal and a myeloid differentiation bias. However, the drivers and mechanisms that underpin this fundamental switch are not understood. HSCs produce genotoxic formaldehyde that requires protection by the detoxification enzymes ALDH2 and ADH5 and the Fanconi anemia (FA) DNA repair pathway. We find that the HSCs in young Aldh2-/-Fancd2-/- mice harbor a transcriptomic signature equivalent to aged wild-type HSCs, along with increased epigenetic age, telomere attrition, and myeloid-biased differentiation quantified by single HSC transplantation. In addition, the p53 response is vigorously activated in Aldh2-/-Fancd2-/- HSCs, while p53 deletion rescued this aged HSC phenotype. To further define the origins of the myeloid differentiation bias, we use a GFP genetic reporter to find a striking enrichment of Vwf+ myeloid and megakaryocyte-lineage-biased HSCs. These results indicate that metabolism-derived formaldehyde-DNA damage stimulates the p53 response in HSCs to drive accelerated aging.

Keywords:  DNA damage; DNA-damage response; aging; aldehydes; hematopoiesis; myeloid bias; p53

DOI:  https://doi.org/10.1016/j.molcel.2023.05.035
Leukemia. 2023 Jun 22.

MCL1 regulates AML cells metabolism via direct interaction with HK2. Metabolic signature at onset predicts overall survival in AMLs' patients.

Gianfranco Catalano, Alessandra Zaza, Cristina Banella, Elvira Pelosi, Germana Castelli, Elisabetta de Marinis, Ariela Smigliani, Serena Travaglini, Tiziana Ottone, Mariadomenica Divona, Maria Ilaria Del Principe, Francesco Buccisano, Luca Maurillo, Emanuele Ammatuna, Ugo Testa, Clara Nervi, Adriano Venditti, Maria Teresa Voso, Nelida Ines Noguera.

We characterize the metabolic background in distinct Acute Myeloid Leukemias (AMLs), by comparing the metabolism of primary AML blasts isolated at diagnosis with that of normal hematopoietic maturing progenitors, using the Seahorse XF Agilent. Leukemic cells feature lower spare respiratory (SRC) and glycolytic capacities as compared to hematopoietic precursors (i.e. day 7, promyelocytes). According with Proton Leak (PL) values, AML blasts can be grouped in two well defined populations. The AML group with blasts presenting high PL or high basal OXPHOS plus high SRC levels had shorter overall survival time and significantly overexpressed myeloid cell leukemia 1 (MCL1) protein. We demonstrate that MCL1 directly binds to Hexokinase 2 (HK2) on the outer mitochondrial membrane (OMM). Overall, these results suggest that high PL and high SRC plus high basal OXPHOS levels at disease onset, arguably with the concourse of MCL1/HK2 action, are significantly linked with shorter overall survival time in AML. Our data describe a new function for MCL1 protein in AMLs' cells: by forming a complex with HK2, MCL1 co-localizes to VDAC on the OMM, thus inducing glycolysis and OXPHOS, ultimately conferring metabolic plasticity and promoting resistance to therapy.

DOI: https://doi.org/10.1038/s41375-023-01946-5
Am J Hematol. 2023 Jun 19.

Real-world effectiveness of intensive chemotherapy with 7&3 versus venetoclax and hypomethylating agent in acute myeloid leukemia.

Andrew H Matthews, Alexander E Perl, Selina M Luger, Saar I Gill, Catherine Lai, David L Porter, Sarah Skuli, Ximena Jordan Bruno, Martin P Carroll, Craig W Freyer, Alison Carulli, Daria V Babushok, Noelle V Frey, Elizabeth O Hexner, Mary Ellen Martin, Shannon R McCurdy, Edward A Stadtmauer, Alison W Loren, Vikram R Paralkar, Ivan P Maillard, Keith W Pratz.

Intensive chemotherapy with cytarabine and anthracycline (7&3) remains the standard therapy for patients medically fit for induction, but the assessment of fitness remains controversial. Venetoclax and hypomethylating agent (ven/HMA) combination therapy has improved outcomes in unfit patients but no prospective study has assessed ven/HMA versus 7&3 as initial therapy in older, fit patients. Given no studies and expectation of ven/HMA use in patients outside of trial criteria, we evaluated retrospective outcomes among newly diagnosed patients. A nationwide electronic health record (EHR)-derived database and the University of Pennsylvania EHR identified 312 patients receiving 7&3 and 488 receiving ven/HMA who were 60-75 years old without history of organ failure. Ven/HMA patients were older and more likely to have secondary AML, adverse cytogenetics, and adverse mutations. Median overall survival (OS) for patients receiving intensive chemotherapy was 22 versus 10 months for ven/HMA (HR 0.53, 95% CI 0.40-0.60). Controlling for measured baseline characteristic imbalances reduced survival advantage by half (HR 0.71, 95% CI 0.53-0.94). A sub-group of patients with equipoise, likelihood at least 30%-70% of receiving either treatment, had similar OS outcomes (HR 1.10, 95% CI 0.75-1.6). Regarding safety outcomes, 60-day mortality was higher for ven/HMA (15% vs. 6% at 60 days) despite higher documented infections and febrile neutropenia for 7&3. In this multicenter real-word dataset, patients selected for intensive chemotherapy had superior OS but a large group had similar outcomes with ven/HMA. Prospective randomized studies, controlling for both measured and unmeasured confounders, must confirm this outcome.

DOI: https://doi.org/10.1002/ajh.26991
iScience. 2023 Jun 16. 26(6): 106943

Cell-cell interactome of the hematopoietic niche and its changes in acute myeloid leukemia.

Sarah Ennis, Alessandra Conforte, Eimear O'Reilly, Javid Sabour Takanlu, Tatiana Cichocka, Sukhraj Pal Dhami, Pamela Nicholson, Philippe Krebs, Pilib Ó Broin, Eva Szegezdi.

  The bone marrow (BM) is a complex microenvironment, coordinating the production of billions of blood cells every day. Despite its essential role and its relevance to hematopoietic diseases, this environment remains poorly characterized. Here we present a high-resolution characterization of the niche in health and acute myeloid leukemia (AML) by establishing a single-cell gene expression database of 339,381 BM cells. We found significant changes in cell type proportions and gene expression in AML, indicating that the entire niche is disrupted. We then predicted interactions between hematopoietic stem and progenitor cells (HSPCs) and other BM cell types, revealing a remarkable expansion of predicted interactions in AML that promote HSPC-cell adhesion, immunosuppression, and cytokine signaling. In particular, predicted interactions involving transforming growth factor β1 (TGFB1) become widespread, and we show that this can drive AML cell quiescence in vitro. Our results highlight potential mechanisms of enhanced AML-HSPC competitiveness and a skewed microenvironment, fostering AML growth.

Keywords:  Cell biology; Hematology; Molecular biology

DOI:  https://doi.org/10.1016/j.isci.2023.106943
Am J Hematol. 2023 Jun 22.

Luspatercept use for lower risk myelodysplastic syndromes: Active but not enough.

Mrinal M Patnaik, Ayalew Tefferi.

DOI: https://doi.org/10.1002/ajh.27003
Haematologica. 2023 Jun 22.

Exclusion of persistent mutations in splicing factor genes and isocitrate dehydrogenase 2 improves the prognostic power of molecular measurable residual disease assessment in acute myeloid leukemia.

Tracy Murphy, Jinfeng Zou, Andrea Arruda, Ting Ting Wang, Zhen Zhao, Yangqiao Zheng, Vikas Gupta, Dawn Maze, Caroline McNamara, Mark D Minden, Aaron Schimmer, Hassan Sibai, Karen Yee, Jose-Mario Capo-Chichi, Tracy Stockley, Andre Schuh, Scott V Bratman, Steven M Chan.

Not available.

DOI: https://doi.org/10.3324/haematol.2023.283510
Best Pract Res Clin Haematol. 2023 Jun;pii: S1521-6926(23)00029-4. [Epub ahead of print]36(2): 101468

Measurable residual disease in patients undergoing allogeneic transplant for acute myeloid leukemia.

Zoë C Wong, Laura W Dillon, Christopher S Hourigan.

  The most common indication for allogeneic hematopoietic cell transplant (alloHCT) is maintenance of remission after initial treatment for patients with acute myeloid leukemia (AML). Loss of remission, relapse, remains however the most frequent cause of alloHCT failure. There is strong evidence that detectable persistent disease burden ("measurable residual disease", MRD) in patients with AML in remission prior to alloHCT is associated with increased risk of post-transplant relapse. MRD status as a summative assessment of response to pre-transplant therapy may allow superior patient-personalized risk stratification compared with models solely incorporating pre-treatment variables. An optimal methodology for AML MRD detection has not yet been established, but molecular methods such as DNA-sequencing may have additional prognostic utility compared to current approaches. There is growing evidence that intervention on AML MRD positivity may improve post-transplant outcomes. New initiatives will generate actionable data on the clinical utility of AML MRD testing for patients undergoing alloHCT.

Keywords:  AML; AlloHCT; HCT; MRD; Minimal residual disease

DOI:  https://doi.org/10.1016/j.beha.2023.101468
Clin Cancer Res. 2023 Jun 21. OF1-OF7

A Metabolically Optimized, Noncytotoxic Low-Dose Weekly Decitabine/Venetoclax in MDS and AML.

David Levitz, Yogen Saunthararajah, Kateryna Fedorov, Lauren C Shapiro, Ioannis Mantzaris, Aditi Shastri, Noah Kornblum, R Alejandro Sica, Nishi Shah, Marina Konopleva, Kira Gritsman, Ira Braunschweig, Dennis L Cooper, Kith Pradhan, Amit Verma, Eric J Feldman, Mendel Goldfinger.

PURPOSE: Venetoclax (VEN) added to the hypomethylating agents (HMA) decitabine or azacitidine is the new standard of care for elderly patients with acute myeloid leukemia (AML) and is being evaluated in myelodysplastic syndrome (MDS). Current dosing of HMA/VEN relies on leukemia suppression through cytotoxicity which also impacts normal hematopoiesis. A regimen using once-weekly low-dose decitabine (LDDec) has demonstrated activity in myeloid malignancies. To overcome the severe myelosuppression often seen with HMA/VEN, we evaluated a once-weekly dosing regimen of VEN and LDDec in elderly and/or frail patients who were felt less likely to tolerate severe myelosuppression.
PATIENTS AND METHODS: This is a retrospective, single-center analysis of patients with AML, MDS, or chronic myelomonocytic leukemia treated with a once-weekly LDDec/VEN regimen. We also compare this regimen with a cohort treated with standard dosing HMA/VEN.
RESULTS: In a retrospective cohort of 39 patients, the overall response rate for patients receiving LDDec/VEN for first-line AML and MDS was 88% and 64%, respectively. In patients with TP53 mutations, the composite complete response rate was 71% and the median overall survival was 10.7 months. When compared with 36 patients receiving standard dose HMA/VEN, the LDDec/VEN patients had a longer time on therapy (175 vs. 78 days; P = 0.014) and a trend toward a higher rate of transfusion independence (47% vs. 26%; P = 0.33). Neutropenic fever occurred in 31% of patients, with a median of one hospitalization at any point during treatment.
CONCLUSIONS: This preliminary clinical experience, although retrospective, provides proof-of-activity of noncytotoxic DNA methyltransferase 1-targeting by allowing frequent, sustained drug exposure often not possible with standard HMA/VEN regimens.

DOI: https://doi.org/10.1158/1078-0432.CCR-23-0842
bioRxiv. 2023 Jun 07. pii: 2023.05.13.540665. [Epub ahead of print]

DNA damage primes hematopoietic stem cells for direct megakaryopoiesis.

Corey M Garyn, Oriol Bover, John W Murray, Ma Jing, Karen Salas-Briceno, Susan R Ross, Hans-Willem Snoeck.

Hematopoietic stem cells (HSCs) reside in the bone marrow (BM), can self-renew, and generate all cells of the hematopoietic system. 1 Most hematopoietic lineages arise through successive, increasingly lineage-committed progenitors. In contrast, megakaryocytes (MKs), hyperploid cells that generate platelets essential to hemostasis, can derive rapidly and directly from HSCs. 2 The underlying mechanism is unknown however. Here we show that DNA damage and subsequent arrest in the G2 phase of the cell cycle rapidly induce MK commitment specifically in HSCs, but not in progenitors, through an initially predominantly post-transcriptional mechanism. Cycling HSCs show extensive replication-induced DNA damage associated with uracil misincorporation in vivo and in vitro . Consistent with this notion, thymidine attenuated DNA damage, rescued HSC maintenance and reduced the generation of CD41 + MK-committed HSCs in vitro . Similarly, overexpression of the dUTP-scavenging enzyme, dUTPase, enhanced in vitro maintenance of HSCs. We conclude that a DNA damage response drives direct megakaryopoiesis and that replication stress-induced direct megakaryopoiesis, at least in part caused by uracil misincorporation, is a barrier to HSC maintenance in vitro . DNA damage-induced direct megakaryopoiesis may allow rapid generation of a lineage essential to immediate organismal survival, while simultaneously removing damaged HSCs and potentially avoiding malignant transformation of self-renewing stem cells.

DOI: https://doi.org/10.1101/2023.05.13.540665
Haematologica. 2023 Jun 22.

Efficacy and toxicity of midostaurin with idarubicin and cytarabine induction in FLT3-mutated acute myeloid leukemia.

Julia S Lee, Charlotte B Wagner, Stacy Prelewicz, Heena P Kurish, Robert Walchack, Danielle A Cenin, Seema Patel, Mimi Lo, Danielle Schlafer, Belinda Kt Li, R Donald Harvey Iii, Bestis Wasef, Jian Ying, Tibor Kovacsovics.

Not available.

DOI: https://doi.org/10.3324/haematol.2022.281967
PLoS Comput Biol. 2023 Jun 23. 19(6): e1010459

Community detection in empirical kinase networks identifies new potential members of signalling pathways.

Celia De Los Angeles Colomina Basanta, Marya Bazzi, Maruan Hijazi, Conrad Bessant, Pedro R Cutillas.

Phosphoproteomics allows one to measure the activity of kinases that drive the fluxes of signal transduction pathways involved in biological processes such as immune function, senescence and cell growth. However, deriving knowledge of signalling network circuitry from these data is challenging due to a scarcity of phosphorylation sites that define kinase-kinase relationships. To address this issue, we previously identified around 6,000 phosphorylation sites as markers of kinase-kinase relationships (that may be conceptualised as network edges), from which empirical cell-model-specific weighted kinase networks may be reconstructed. Here, we assess whether the application of community detection algorithms to such networks can identify new components linked to canonical signalling pathways. Phosphoproteomics data from acute myeloid leukaemia (AML) cells treated separately with PI3K, AKT, MEK and ERK inhibitors were used to reconstruct individual kinase networks. We used modularity maximisation to detect communities in each network, and selected the community containing the main target of the inhibitor used to treat cells. These analyses returned communities that contained known canonical signalling components. Interestingly, in addition to canonical PI3K/AKT/mTOR members, the community assignments returned TTK (also known as MPS1) as a likely component of PI3K/AKT/mTOR signalling. We drew similar insights from an external phosphoproteomics dataset from breast cancer cells treated with rapamycin and oestrogen. We confirmed this observation with wet-lab laboratory experiments showing that TTK phosphorylation was decreased in AML cells treated with AKT and MTOR inhibitors. This study illustrates the application of community detection algorithms to the analysis of empirical kinase networks to uncover new members linked to canonical signalling pathways.

DOI: https://doi.org/10.1371/journal.pcbi.1010459
Blood Adv. 2023 Jun 23. pii: bloodadvances.2023010382. [Epub ahead of print]

The transcriptomic landscape of normal and ineffective erythropoiesis at single-cell resolution.

Raymond T Doty, Christopher G Lausted, Adam D Munday, Zhantao Yang, Xiaowei Yan, Changting Meng, Qiang Tian, Janis L Abkowitz.

The anemias of myelodysplastic syndrome (MDS) and Diamond Blackfan anemia (DBA) are generally macrocytic, always reflect ineffective erythropoiesis, yet result from diverse genetic mutations. To delineate shared mechanisms that lead to cell death, we studied the fate of single erythroid marrow cells from individuals with DBA and MDS-5q. We defined an unhealthy (vs. healthy) differentiation trajectory using transcriptional pseudotime and cell surface proteins. The pseudotime trajectories diverge immediately after cells upregulate transferrin receptor (CD71), import iron, and initiate heme synthesis, although cell death occurs much later. Cells destined to die highly express heme responsive genes, including ribosomal protein and globin genes, while surviving cells downregulate heme synthesis and upregulate DNA damage response, hypoxia and HIF1 pathways. Surprisingly, 24±12% of cells from control subjects follow the unhealthy trajectory, implying that heme might serve as a rheostat directing cells to live or die. When heme synthesis was inhibited with succinylacetone, more DBA cells followed the healthy trajectory and survived. We also noted high numbers of messages with retained introns that increased as erythroid cells matured, confirmed the rapid cycling of CFU-E, and demonstrated that cell cycle timing is an invariant property of differentiation stage. Including unspliced RNA in pseudotime determinations allowed us to reliably align independent datasets and accurately query stage-specific transcriptomic changes. MDS-5q (unlike DBA) results from somatic mutation, so many normal (unmutated) erythroid cells persist. By independently tracking erythroid differentiation of cells with and without chromosome 5q deletions, we gained insight into why 5q+ cells cannot expand to prevent anemia.

DOI: https://doi.org/10.1182/bloodadvances.2023010382
Haematologica. 2023 Jun 22.

Can Measurable Residual Disease (MRD) assessment be reliably used to defer allogeneic stem cell transplant in patients with intermediate-risk acute myeloid leukemia?

Mahesh Swaminathan, Farhad Ravandi.

Not available.

DOI: https://doi.org/10.3324/haematol.2023.283120
Exp Hematol. 2023 Jun 16. pii: S0301-472X(23)00254-0. [Epub ahead of print]

BCR-ABL promotes hematopoietic stem and progenitor cell formation in embryonic stem cells.

Jérôme Artus, Alina Zenych, Isidora Simanic, Christophe Desterke, Denis Clay, Sonia Saïm, Yousef Ijjeh, Lucas Eduardo Botelho de Souza, Sabrina Coignard, Annelise Bennaceur-Griscelli, Ali G Turhan, Adlen Foudi.

  Generating Hematopoietic Stem Cells (HSCs) from Pluripotent Stem Cells (PSCs) has been a long-lasting quest in the field of hematopoiesis. Previous studies suggested that enforced expression of BCR-ABL, the unique oncogenic driver of Chronic Myelogeneous Leukemia (CML), in Embryonic Stem Cells (ESCs)-derived hematopoietic cells is sufficient to confer long-term in vivo repopulating potential. To precisely uncover the molecular events regulated by the Tyrosine-kinase activity of BCR-ABL1 (p210) during the course of hematopoietic differentiation, we engineered a Tet-ON inducible system to modulate its expression in murine ESC. We showed in unique site-directed knock-in ESC model, that BCR-ABL expression tightly regulated by doxycycline (dox) controls the formation and the maintenance of immature hematopoietic progenitors. Interestingly, these progenitors can be expanded in vitro for several passages in the presence of dox. Our analysis of cell surface markers and transcriptome compared to wild-type fetal and adult HSCs unraveled a similar molecular signature. LTC-IC assay confirmed their self-renewal capacities albeit with a differentiation bias towards erythroid and myeloid cells. Collectively, our novel Tet-ON system represents a unique in vitro model to shed lights on ESC-derived hematopoiesis, CML initiation and maintenance.

Keywords:  BCR-ABL; chronic myeloid leukemia; hematopoiesis; pluripotent stem cell

DOI:  https://doi.org/10.1016/j.exphem.2023.06.002
Blood. 2023 Jun 22. 141(25): 3014-3015

Getting to the core of ADAR2 activity in AML.

Kathleen Steel, Catriona Jamieson.

DOI: https://doi.org/10.1182/blood.2023019923
Curr Res Transl Med. 2023 Jun 13. pii: S2452-3186(23)00022-3. [Epub ahead of print]71(3): 103398

Advanced Systemic Mastocytosis with associated haematological neoplasm: Treatment with avapritinib can facilitate successful bridge to allogeneic haematopoietic cell transplant.

P Sriskandarajah, D P McLornan, C Oni, A J Wilson, C Woodley, M Ciesielska, K Raj, R Dillon, M Ethell, J Chacko, K Orchard, D H Radia.

  Advanced systemic mastocytosis (AdvSM) is a rare, life-limiting mast cell (MC) neoplasm, with approximately 70% patients having an associated haematological neoplasm (AHN). Avapritinib, a selective tyrosine kinase inhibitor targeting KIT D816V, has shown potent activity translating clinically into durable responses in the phase 1 EXPLORER (NCT02561988) and phase 2 PATHFINDER (NCT03580655) studies. We report three patients with AdvSM-AHN on avapritinib who achieved complete remission (CR) of SM and were successfully bridged to allogeneic haematopoietic cell transplant (allo-HCT). Two cases additionally highlight the risk of clonal evolution within the AHN component and requirement for close monitoring while on targeted therapy.

Keywords:  Allogeneic transplant; Clonal evolution; Mastocytosis; Targeted therapy

DOI:  https://doi.org/10.1016/j.retram.2023.103398
Cancers (Basel). 2023 May 12. pii: 2731. [Epub ahead of print]15(10):

Preclinical Validation of an Advanced Therapy Medicinal Product Based on Cytotoxic T Lymphocytes Specific for Mutated Nucleophosmin (NPM1mut) for the Treatment of NPM1mut-Acute Myeloid Leukemia.

Marica De Cicco, Ivana Lagreca, Sabrina Basso, Patrizia Barozzi, Stella Muscianisi, Alba Bianco, Giovanni Riva, Sara Di Vincenzo, Chiara Pulvirenti, Davide Sapuppo, Mariangela Siciliano, Vittorio Rosti, Anna Candoni, Marco Zecca, Fabio Forghieri, Mario Luppi, Patrizia Comoli.

  Acute myeloid leukemia (AML) with nucleophosmin (NPM1) genetic mutations is the most common subtype in adult patients. Refractory or relapsed disease in unfit patients or after allogeneic hematopoietic stem cell transplantation (allo-HSCT) has a poor prognosis. NPM1-mutated protein, stably expressed on tumor cells but not on normal tissues, may serve as an ideal target for NPM1-mutated AML immunotherapy. The study aim was to investigate the feasibility of producing mutated-NPM1-specific cytotoxic T cells (CTLs) suitable for somatic cell therapy to prevent or treat hematologic relapse in patients with NPM1-mutated AML. T cells were expanded or primed from patient or donor peripheral blood mononuclear cells by NPM1-mutated protein-derived peptides, and tested for leukemia antigen-targeted cytotoxic activity, cytokine production and hematopoietic precursor inhibitory effect. We found that mutated-NPM1-specific CTLs, displaying specific cytokine production and high-level cytotoxicity against patients' leukemia blasts, and limited inhibitory activity in clonogenic assays, could be obtained from both patients and donors. The polyfunctional mutated-NPM1-specific CTLs included both CD8+ and CD4+ T cells endowed with strong lytic capacity. Our results suggest that mutated-NPM1-targeted CTLs may be a useful therapeutic option to control low-tumor burden relapse following conventional chemotherapy in older NPM1-mutated AML patients or eradicate persistent MRD after HSCT.

Keywords:  NPM1 mutation; T cell therapy; acute myeloid leukemia; hematopoietic stem cell transplantation; minimal residual disease

DOI:  https://doi.org/10.3390/cancers15102731
Blood Adv. 2023 Jun 23. pii: bloodadvances.2022009652. [Epub ahead of print]

Comparing the value of mono- versus coculture for high-throughput compound screening in hematological malignancies.

Sophie A Herbst, Vladislav Kim, Tobias Roider, Eva C Schitter, Peter-Martin Bruch, Nora Liebers, Carolin Kolb, Mareike Knoll, Junyan Lu, Peter Dreger, Carsten Müller-Tidow, Thorsten Zenz, Wolfgang Huber, Sascha Dietrich.

Large-scale compound screens are a powerful model system for understanding variability of treatment response and for discovering druggable tumor vulnerabilities of hematological malignancies. However, as mostly performed in a monoculture of tumor cells, these assays disregard modulatory effects of the in vivo microenvironment. It is an open question whether and to what extent coculture with bone marrow stromal cells could improve the biological relevance of drug testing assays over monoculture. Here, we established a high throughput platform to measured ex vivo sensitivity of 108 primary blood cancer samples to 50 drugs in monoculture and in coculture with bone marrow stromal cells. Stromal coculture conferred resistance to 52 % of compounds in chronic lymphocytic leukemia (CLL) and to 36 % of compounds in acute myeloid leukemia (AML), including chemotherapeutics, BCR inhibitors, proteasome inhibitors and BET inhibitors. While most of the remaining drugs were similarly effective in mono- and coculture, oOnly the JAK inhibitors ruxolitinib and tofacitinib exhibited increased efficacy in AML and CLL stromal coculture. We further confirmed the importance of JAK-STAT signaling for stroma-mediated resistance by showing that stromal cells induce phosphorylation of STAT3 in CLL cells. We genetically characterized the 108 cancer samples and found that drug-gene associations agreed strongly correlated well between mono- and coculture. OverallHowever, effect sizes were lower in coculture, thus with more drug-gene associations were detected in monoculture than in coculture. Our results suggest justifies a two-step strategy for drug perturbation testing, with large-scale screening performed in monoculture, followed by focused evaluation of potential stroma-mediated resistances in coculture.

DOI: https://doi.org/10.1182/bloodadvances.2022009652
Commun Biol. 2023 Jun 23. 6(1): 664

NUP98 and RAE1 sustain progenitor function through HDAC-dependent chromatin targeting to escape from nucleolar localization.

Amy E Neely, Laura A Blumensaadt, Patric J Ho, Sarah M Lloyd, Junghun Kweon, Ziyou Ren, Xiaomin Bao.

Self-renewing somatic tissues rely on progenitors to support the continuous tissue regeneration. The gene regulatory network maintaining progenitor function remains incompletely understood. Here we show that NUP98 and RAE1 are highly expressed in epidermal progenitors, forming a separate complex in the nucleoplasm. Reduction of NUP98 or RAE1 abolishes progenitors' regenerative capacity, inhibiting proliferation and inducing premature terminal differentiation. Mechanistically, NUP98 binds on chromatin near the transcription start sites of key epigenetic regulators (such as DNMT1, UHRF1 and EZH2) and sustains their expression in progenitors. NUP98's chromatin binding sites are co-occupied by HDAC1. HDAC inhibition diminishes NUP98's chromatin binding and dysregulates NUP98 and RAE1's target gene expression. Interestingly, HDAC inhibition further induces NUP98 and RAE1 to localize interdependently to the nucleolus. These findings identified a pathway in progenitor maintenance, where HDAC activity directs the high levels of NUP98 and RAE1 to directly control key epigenetic regulators, escaping from nucleolar aggregation.

DOI: https://doi.org/10.1038/s42003-023-05043-2
Cell Rep. 2023 Jun 17. pii: S2211-1247(23)00676-9. [Epub ahead of print]42(6): 112665

ETV2 primes hematoendothelial gene enhancers prior to hematoendothelial fate commitment.

Jeffrey D Steimle, Chul Kim, Megan Rowton, Rangarajan D Nadadur, Zhezhen Wang, Matthew Stocker, Andrew D Hoffmann, Erika Hanson, Junghun Kweon, Tanvi Sinha, Kyunghee Choi, Brian L Black, John M Cunningham, Ivan P Moskowitz, Kohta Ikegami.

  Mechanisms underlying distinct specification, commitment, and differentiation phases of cell fate determination remain undefined due to difficulties capturing these processes. Here, we interrogate the activity of ETV2, a transcription factor necessary and sufficient for hematoendothelial differentiation, within isolated fate intermediates. We observe transcriptional upregulation of Etv2 and opening of ETV2-binding sites, indicating new ETV2 binding, in a common cardiac-hematoendothelial progenitor population. Accessible ETV2-binding sites are active at the Etv2 locus but not at other hematoendothelial regulator genes. Hematoendothelial commitment coincides with the activation of a small repertoire of previously accessible ETV2-binding sites at hematoendothelial regulators. Hematoendothelial differentiation accompanies activation of a large repertoire of new ETV2-binding sites and upregulation of hematopoietic and endothelial gene regulatory networks. This work distinguishes specification, commitment, and sublineage differentiation phases of ETV2-dependent transcription and suggests that the shift from ETV2 binding to ETV2-bound enhancer activation, not ETV2 binding to target enhancers, drives hematoendothelial fate commitment.

Keywords:  CP: Molecular biology; CP: Stem cell research; ETV2; VEGF; cell fate; commitment; differentiation; endothelial development; hematoendothelium; hematopoiesis; pioneer factors; transcriptional regulation

DOI:  https://doi.org/10.1016/j.celrep.2023.112665
Blood Adv. 2023 Jun 23. pii: bloodadvances.2023010310. [Epub ahead of print]

Tacrolimus/methotrexate vs tacrolimus/reduced-dose methotrexate/mycophenolate for graft-vs-host disease prevention.

Betty K Hamilton, Lisa A Rybicki, Hong Li, Taylor Lucas, Donna Corrigan, Matt E Kalaycio, Ronald M Sobecks, Rabi Hanna, Seth J Rotz, Robert M Dean, Aaron T Gerds, Deepa Jagadeesh, Claudio Brunstein, Craig S Sauter, Edward A Copelan, Navneet S Majhail.

Tacrolimus (Tac)/methotrexate (MTX) is standard graft-versus-host disease (GVHD) prophylaxis, however, associated with several toxicities. Tac, reduced dose ("mini")-MTX, mycophenolate mofetil (MMF) has been used, but never compared to standard MTX. We performed a randomized trial comparing Tac/MTX (Full-MTX) to Tac/mini-MTX/MMF (Mini-MTX/MMF) for GVHD prevention after allogeneic hematopoietic cell transplantation (HCT). Patients (pts) receiving first myeloablative HCT using an 8/8 HLA-matched donor were eligible. Primary endpoints were incidence of acute (a)GVHD, mucositis, and engraftment. Secondary endpoints included chronic (c)GVHD, organ toxicity, infection, relapse, non-relapse mortality (NRM), and overall survival (OS). Ninety-six pts were randomized to Full-MTX (N=49) or Mini-MTX (N=47). The majority (86%) used bone marrow grafts. There was no significant difference in day 100 grade 2-4 aGVHD (28% Mini-MTX/MMF vs 27% Full-MTX, P=0.41), however higher grade 3-4 aGVHD (13% vs 4%, P=0.07) with Mini-MTX/MMF. Mini-MTX/MMF pts had lower grade 3-4 mucositis (57% vs 82%, P=0.010), and faster neutrophil engraftment (median 15 vs 17 days, P<0.001). There were no significant differences in moderate-severe cGVHD at 1 year (23% vs 20%, P=0.14) or infections. Mini-MTX/MMF pts experienced less nephrotoxicity (2% vs 26%, P<0.001) and less respiratory failure (6% versus 18%, P=0.03). There was no difference in 1-year relapse (19% vs 21%, P=0.89) or OS (72% vs. 71%, P=0.08), and Mini-MTX/MMF was associated with lower but non-significant NRM (11% vs 22%), P=0.06. Compared to Full-MTX, Mini-MTX/MMF was associated with no difference in grade 2-4 aGVHD and a more favorable toxicity profile. The higher severe aGVHD warrants additional study to further optimize this regimen.

DOI: https://doi.org/10.1182/bloodadvances.2023010310
J Clin Invest. 2023 Jun 20. pii: e162201. [Epub ahead of print]

Ruxolitinib improves hematopoietic regeneration by restoring mesenchymal stromal cell function in acute graft-versus-host disease.

Yan Lin, Quan Gu, Shihong Lu, Zengkai Pan, Zining Yang, Yapu Li, Shangda Yang, Yanling Lv, Zhaofeng Zheng, Guohuan Sun, Fanglin Gou, Chang Xu, Xiangnan Zhao, Fengjiao Wang, Chenchen Wang, Shiru Yuan, Xiaobao Xie, Yang Cao, Yue Liu, Weiying Gu, Tao Cheng, Hui Cheng, Xiaoxia Hu.

  Acute graft-versus-host disease (aGVHD) is a severe complication of allogeneic hematopoietic stem cell transplantation. Hematopoietic dysfunction accompanied by severe aGVHD, which may be caused by niche impairment, is a long-standing clinical problem. However, how the bone marrow (BM) niche is damaged in aGVHD hosts is poorly defined. To comprehensively address this question, we employed a haplo-MHC-matched transplantation aGVHD murine model and performed single-cell RNA sequencing of non-hematopoietic BM cells. Transcriptional analysis showed that BM mesenchymal stromal cells (BMSCs) were severely affected with a reduction in cell ratio, abnormal metabolism, compromised differentiation potential and defective hematopoietic supportive function, which were validated by functional assays. We found that ruxolitinib, a selective JAK1/2 inhibitor, ameliorated aGVHD-related hematopoietic dysfunction through direct effect on recipient BMSCs, resulting in improved proliferation ability, adipogenesis/osteogenesis potential, mitochondrial metabolism capacity and crosstalk with donor-derived hematopoietic stem/progenitor cells. By inhibiting the JAK2/STAT1 pathway, ruxolitinib maintained long-term improvement of aGVHD BMSC function. Additionally, ruxolitinib pretreatment in vitro primed BMSCs to better support donor-derived hematopoiesis in vivo. These observations in the murine model were validated in patient samples. Overall, our findings suggest that ruxolitinib can directly restore BMSC function via JAK2/STAT1 pathway and in turn, improve the hematopoietic dysfunction caused by aGVHD.

Keywords:  Bone marrow transplantation; Stem cells

DOI:  https://doi.org/10.1172/JCI162201
Haematologica. 2023 Jun 22.

Genomic breakpoint specific monitoring of measurable residual disease in pediatric non-standard risk acute myeloid leukemia.

Margarita Maurer-Granofszky, Stefan Kohrer, Susanna Fischer, Angela Schumich, Karin Nebral, Patrizia Larghero, Claus Meyer, Astrid Mecklenbrauker, Nora Muhlegger, Rolf Marschalek, Oskar A Haas, Renate Panzer-Grumayer, Michael N Dworzak.

Pediatric acute myeloid leukemia (pedAML) is a highly heterogeneous disease making standardized measurable residual disease (MRD) assessment challenging. Currently, patient-specific DNA-based assays are only rarely applied for MRD assessment in pedAML. We tested whether quantification of genomic breakpoint specific sequences via quantitative PCR (gDNA-PCR) provides a reliable means of MRD quantification in children with non-standard risk (non- SR) AML and compared its results to those obtained with state-of-the art 10-color flow cytometry (FCM). Breakpoint specific gDNA- PCR assays were established according to the guidelines of the Euro-MRD consortium. FCM-MRD assessment was performed according to the European Leukemia Network (ELN) guidelines with adaptations for pedAML. Of 77 consecutively recruited non-SR pedAML cases 49 (64%) carried a chromosomal translocation potentially suitable for MRD quantification. Genomic breakpoint analysis returned a specific DNA sequence in 100% (41/41) of the cases submitted for investigation. MRD levels were evaluated using gDNA-PCR in 243 follow-up (FUP) samples from 36 patients, achieving a quantitative range (QR) of at least 10-4 in 231/243 (95%) of samples. Comparing gDNA-PCR with FCM-MRD data in 183 bone marrow (BM) FUP samples at various therapy timepoints resulted in a high concordance of 90,2% when considering the cut-off of ≥0,1%. Both methodologies outperformed morphologic assessment. We conclude that MRD monitoring by gDNA-PCR is feasible in pediatric AML with traceable genetic rearrangements and correlates well with FCM-MRD in the currently applied clinically relevant range, while being more sensitive below that. The methodology should be evaluated in larger patient cohorts to pave the way for clinical application.

DOI: https://doi.org/10.3324/haematol.2022.282424
Ann Hematol. 2023 Jun 21.

Comparison of outcomes for patients with acute myeloid leukemia undergoing haploidentical stem cell transplantation in first and second complete remission.

Wen-Jing Yu, Yu-Qian Sun, Lan-Ping Xu, Xiao-Hui Zhang, Kai-Yan Liu, Xiao-Jun Huang, Yu Wang.

  There was no consensus on whether prognostic advantages existed when transplant conducted at first complete remission (CR1) stage than at second complete remission (CR2) stage for patients with AML who received haploidentical hematological stem cell transplantation (haplo-HSCT). In 768 consecutive AML patients who received haplo-HSCT from January 2014 to December 2017, a 1:2 ratio matched-pair analysis was performed, 69 patients who in CR2 group and 138 CR1 patients were enrolled. Hematopoietic recovery, graft versus host disease (GVHD), relapse, transplant related mortality (TRM), disease-free survival (DFS) and overall survival (OS) were compared in two groups, and further evaluated in low-, intermediate-, and high-risk subgroups. The cumulative incidences of 30-day myeloid recovery and 90-day platelet recovery were comparable in CR1 and CR2 groups. The cumulative incidences of grade II-IV and grade III-IV aGVHD were not significantly different. The cumulative incidences of relapse at 3-year and 5-year in these two groups were 12.4% versus 11.6% (P = 0.880) and 12.4% versus 17.5% (P = 0.322). The cumulative incidences of TRM at 3-year and 5-year were both 10.9% versus 23.2% (P = 0.019). The probability of DFS at 3-year and 5-year were 76.7% versus 65.2% (P = 0.029) and 76.7% versus 59.3% (P = 0.009). The probability of OS at 3-year and 5-year were 81.8% versus 68.1% (P = 0.026) and 76.7% versus 59.3% (P = 0.026). In the intermediate-risk group, TRM was lower in CR1 group, DFS and OS of CR1 group were superior to CR2 group. In conclusion, haplo-HSCT at CR1 stage was of better prognosis for intermediate-risk AML patients than at CR2 stage.

Keywords:  Acute myeloid leukemia; Allogeneic stem cell transplantation; First complete remission; Haploidentical stem cell transplantation; Second complete remission

DOI:  https://doi.org/10.1007/s00277-023-05324-0
Cancer Res. 2023 Jun 19. pii: CAN-22-3860. [Epub ahead of print]

Activation of the cGAS/STING axis in genome-damaged hematopoietic cells does not impact blood cell formation or leukemogenesis.

Nicole Dressel, Loreen Natusch, Clara M Munz, Santiago Costas Ramon, Mina N F Morcos, Anja Loff, Björn Hiller, Christa Haase, Livia Schulze, Patrick Müller, Mathias Lesche, Andreas Dahl, Hella Luksch, Angela Roesen-Wolff, Axel Roers, Rayk Behrendt, Alexander Gerbaulet.

Genome damage is a main driver of malignant transformation, but it also induces aberrant inflammation via the cGAS/STING DNA sensing pathway. Activation of cGAS/STING can trigger cell death and senescence, thereby potentially eliminating genome-damaged cells and preventing against malignant transformation. Here, we report that defective ribonucleotide excision repair (RER) in the hematopoietic system caused genome instability with concomitant activation of the cGAS/STING axis and compromised hematopoietic stem cell function, ultimately resulting in leukemogenesis. Additional inactivation of cGAS, STING, or type I IFN signaling, however, had no detectable effect on blood cell generation and leukemia development in RER-deficient hematopoietic cells. In wild-type mice, hematopoiesis under steady-state conditions and in response to genome damage was not affected by loss of cGAS. Together, this data challenges a role of the cGAS/STING pathway in protecting the hematopoietic system against DNA damage and leukemic transformation.

DOI: https://doi.org/10.1158/0008-5472.CAN-22-3860
Blood. 2023 Jun 20. pii: blood.2022017934. [Epub ahead of print]

The genesis of human hematopoietic stem cells.

Vincenzo Calvanese, Hanna Mikkola.

Developmental hematopoiesis consists of multiple, partially overlapping hematopoietic waves that generate the differentiated blood cells required for embryonic development while establishing a pool of undifferentiated hematopoietic stem cells (HSC) for post-natal life. This multi-layered design where active hematopoiesis migrates through diverse extra- and intra-embryonic tissues has made it difficult to define a roadmap for generating HSCs versus non-self-renewing progenitors, especially in human. Recent single cell studies have helped identify the rare human HSCs at stages when functional assays are unsuitable to distinguish them from progenitors. This approach has made it possible to track the origin of human HSCs to unique type of arterial endothelium in the aorta-gonad-mesonephros (AGM) region, and document novel benchmarks for HSC migration and maturation in the conceptus. These studies have delivered new insights into the intricate process of HSC generation and provided tools to inform the in vitro efforts to replicate the physiological developmental journey from pluripotent stem cells (PSC) via distinct mesodermal and endothelial intermediates to HSCs.

DOI: https://doi.org/10.1182/blood.2022017934
Ann Hematol. 2023 Jun 17.

Allogeneic haematopoietic stem cell transplantation for myelofibrosis: prognostic indicators and the role of JAK2V617F measurable-residual disease monitoring by droplet-digital polymerase chain reaction.

Vivian W K Li, Rita Yim, Paul Lee, Lynn Chin, Lester Au, Garret M K Leung, Joycelyn Sim, Albert K W Lie, Eric Tse, Yok-Lam Kwong, Harinder Gill.

  Relapse after allogeneic haematopoietic stem cell transplantation (HSCT) is one of the key determinants of outcome in myelofibrosis (MF) and remains an important unmet need. In this retrospective single-centre study, we evaluated 35 consecutive patients with MF receiving allogeneic HSCT. At 30 days post-HSCT, full donor chimerism was achieved in 31 patients (88.6%). The median time to neutrophil engraftment was 16.8 (10-42) days and the median time to platelet engraftment was 26 (12-245) days. Four patients (11.4%) experienced primary graft failure. With a median duration of follow-up of 33 (1-223) months, with the 5-year overall survival (OS) and progression-free survival (PFS) were 51.6% and 46.3%, respectively. Relapse after HSCT (P < 0.001), leucocyte count ≥ 18 × 109/L at HSCT (P = 0.003) and accelerated/blast phase disease at HSCT (P < 0.001) were significantly associated with worse OS. Age at HSCT ≥ 54 years (P = 0.01), mutated ETV6 (P = 0.03), leucocyte count ≥ 18 × 109/L (P = 0.02), accelerated/blast phase MF (P = 0.001), and grade 2-3 bone marrow reticulin fibrosis at 12 months post-HSCT (P = 0.002) were significantly associated with worse PFS. JAK2V617F MRD ≥ 0.047 [sensitivity 85.7%; positive predictive value (PPV) 100%; AUC 0.984; P = 0.001] at 6 months and JAK2V617F MRD ≥ 0.009 (sensitivity 100%; PPV 100%; AUC 1.0; P = 0.001) at 12 months were highly predictive of post-HSCT relapse. Inferior OS and PFS were significantly associated with detectable JAK2V617F MRD at 12 months (P = 0.003 and P = 0.0001, respectively).

Keywords:  Allogeneic haematopoietic stem cell transplantation; Droplet digital polymerase chain reaction; Measurable-residual disease; Myelofibrosis

DOI:  https://doi.org/10.1007/s00277-023-05312-4
Haematologica. 2023 Jun 22.

Effect of age and treatment on predictive value of measurable residual disease: implications for clinical management of adult patients with acute myeloid leukemia.

Francesco Mannelli, Matteo Piccini, Sara Bencini, Giacomo Gianfaldoni, Benedetta Peruzzi, Roberto Caporale, Barbara Scappini, Laura Fasano, Elisa Quinti, Gaia Ciolli, Andrea Pasquini, Francesca Crupi, Sofia Pilerci, Fabiana Pancani, Leonardo Signori, Danilo Tarantino, Chiara Maccari, Vivian Paradiso, Francesco Annunziato, Paola Guglielmelli, Alessandro M Vannucchi.

Measurable residual disease (MRD) is a powerful predictor of outcome in acute myeloid leukemia (AML). In the early phases of treatment, MRD refines initial disease risk stratification and is used for the allocation to allogeneic transplant (HSCT). Despite its well-established role, a relatively high fraction of patients eventually relapses albeit achieving MRDneg status. The aim of this work was to assess specifically the influence of baseline features and treatment intensity on the predictive value of an MRDneg status, particularly focusing on MRD2, measured after 2 consecutive chemotherapeutic cycles. Among baseline features, younger MRD2neg patients (.

DOI: https://doi.org/10.3324/haematol.2023.283196
J Clin Oncol. 2023 Jun 19. JCO2300101

Busulfan Plus Fludarabine Compared With Busulfan Plus Cyclophosphamide for AML Undergoing HLA-Haploidentical Hematopoietic Cell Transplantation: A Multicenter Randomized Phase III Trial.

Yiwen Ling, Li Xuan, Na Xu, Fen Huang, Zhiping Fan, Ziwen Guo, Xiaojun Xu, Hui Liu, Ren Lin, Sijian Yu, Haiyan Zhang, Hua Jin, Meiqing Wu, Can Liu, Xinquan Liang, Ruiming Ou, Yuping Zhang, Xiaodan Liu, Hong Qu, Xiao Zhai, Jing Sun, Ying Zhao, Qifa Liu.

PURPOSE: The busulfan plus fludarabine (BuFlu) conditioning regimen has lower transplant-related mortality (TRM) than busulfan plus cyclophosphamide (BuCy) in HLA-matched transplantation. We aimed to compare outcomes of the BuFlu regimen with those of the BuCy regimen in HLA-haploidentical hematopoietic cell transplantation (haplo-HCT).
METHODS: We performed an open-label, randomized phase III trial at 12 hospitals in China. Eligible patients with AML (18-65 years) were randomly assigned 1:1 to receive BuFlu (busulfan 0.8 mg/kg four times per day on days -6 to -3; fludarabine 30 mg/m2 once daily on days -7 to -3) or BuCy (same dose of busulfan; cyclophosphamide 60 mg/kg once daily on days -3 and -2). The primary end point was 1-year TRM in the intention-to-treat population and safety in the per-protocol population. This trial is registered with ClinicalTrials.gov (identifier: NCT02487069) and is complete.
RESULTS: From November 20, 2015, to September 30, 2019, 386 patients were randomly assigned to receive the BuFlu (n = 194) or BuCy (n = 192) regimen. The median follow-up was 55.0 (IQR, 46.5-69.0) months after random assignment. The 1-year TRM was 7.2% (95% CI, 4.1 to 11.4) and 14.1% (95% CI, 9.6 to 19.4; hazard ratio [HR], 0.51; 95% CI, 0.27 to 0.97; P = .041), the 5-year relapse was 17.9% (95% CI, 9.6 to 28.3) and 14.2% (95% CI, 9.1 to 20.5; HR, 1.12; 95% CI, 0.65 to 1.95; P = .670), and the 5-year overall survival was 72.5% (95% CI, 62.2 to 80.4) and 68.2% (95% CI, 58.9 to 75.9; HR, 0.84; 95% CI, 0.56 to 1.26; P = .465) in two groups, respectively. Grade 3 regimen-related toxicity (RRT) was reported for 0 of 191 patients following the BuFlu regimen and 9 (4.7%) of 190 patients following the BuCy regimen (P = .002). At least one type of grade 3-5 adverse event was reported for 130 (68.1%) of the 191 patients and 147 (77.4%) of the 190 patients in two groups, respectively (P = .041).
CONCLUSION: The BuFlu regimen has a lower TRM and RRT and similar relapse for patients with AML undergoing haplo-HCT compared with the BuCy regimen.

DOI: https://doi.org/10.1200/JCO.23.00101
Nat Genet. 2023 Jun 19.

Transcriptomic classes of BCR-ABL1 lymphoblastic leukemia.

Jaeseung C Kim, Michelle Chan-Seng-Yue, Sabrina Ge, Andy G X Zeng, Karen Ng, Olga I Gan, Laura Garcia-Prat, Eugenia Flores-Figueroa, Tristan Woo, Amy Xin Wei Zhang, Andrea Arruda, Shivapriya Chithambaram, Stephanie M Dobson, Amanda Khoo, Shahbaz Khan, Narmin Ibrahimova, Ann George, Anne Tierens, Johann Hitzler, Thomas Kislinger, John E Dick, John D McPherson, Mark D Minden, Faiyaz Notta.

In BCR-ABL1 lymphoblastic leukemia, treatment heterogeneity to tyrosine kinase inhibitors (TKIs), especially in the absence of kinase domain mutations in BCR-ABL1, is poorly understood. Through deep molecular profiling, we uncovered three transcriptomic subtypes of BCR-ABL1 lymphoblastic leukemia, each representing a maturation arrest at a stage of B-cell progenitor differentiation. An earlier arrest was associated with lineage promiscuity, treatment refractoriness and poor patient outcomes. A later arrest was associated with lineage fidelity, durable leukemia remissions and improved patient outcomes. Each maturation arrest was marked by specific genomic events that control different transition points in B-cell development. Interestingly, these events were absent in BCR-ABL1+ preleukemic stem cells isolated from patients regardless of subtype, which supports that transcriptomic phenotypes are determined downstream of the leukemia-initialing event. Overall, our data indicate that treatment response and TKI efficacy are unexpected outcomes of the differentiation stage at which this leukemia transforms.

DOI: https://doi.org/10.1038/s41588-023-01429-4
JCO Precis Oncol. 2023 06;7 e2300132

Clonal Hematopoiesis: Updates and Implications at the Solid Tumor-Immune Interface.

Marco M Buttigieg, Michael J Rauh.

Recent larger-scale studies of patients with cancer and longitudinal population cohorts have revealed how age-related expansions of mutant hematopoietic cells (clonal hematopoiesis [CH]) have differential associations with incident and prevalent cancers and their outcomes. Increasing recognition and deeper understanding of genetic subtypes of CH are yielding insights into the tumor-immune interface that may help to explain the heterogeneous impact of CH on tumorigenesis and treatment. Herein, we update the expanding influence of CH in precision oncology and propose important research and clinical questions to address to effectively manage and harness CH in oncology patients.

DOI: https://doi.org/10.1200/PO.23.00132
Blood Cancer J. 2023 Jun 22. 13(1): 94

Intracranial bleeding in acute promyelocytic leukemia treated with arsenic trioxide based regimens is associated with induction mortality but not with relapse.

Uday Prakash Kulkarni, Sushil Selvarajan, N A Fouzia, Sharon Lionel, Sukesh Chandran Nair, Poonkuzhali Balasubramanian, Thenmozhi Mani, Aby Abraham, Biju George, Vikram Mathews.

DOI: https://doi.org/10.1038/s41408-023-00873-z