bims-tremyl 2024-09-22 papers

bims-tremyl

Biomed News

on Therapy resistance biology in myeloid leukemia

Issue of 2024‒09‒22
28 papers selected by
Paolo Gallipoli, Barts Cancer Institute, Queen Mary University of London

Single or Double Induction With 7 + 3 Containing Standard or High-Dose Daunorubicin for Newly Diagnosed AML: The Randomized DaunoDouble Trial by the Study Alliance Leukemia.
Impact of BCR::ABL1 single nucleotide variants on asciminib efficacy.
Selective degradation of mutant FMS-like tyrosine kinase-3 requires BIM-dependent depletion of heat shock proteins.
Venetoclax-based salvage therapy as bridge-to-transplant is feasible and effective in patients with relapsed/refractory AML.
Outcomes of patients with acute myeloid leukemia treated with intensive therapy after failure of venetoclax-inclusive, less-intensive therapy.
Phosphoproteomics predict response to midostaurin plus chemotherapy in independent cohorts of FLT3-mutated acute myeloid leukaemia.
Randomized Phase III SIERRA Trial of 131I-Apamistamab Before Allogeneic Hematopoietic Cell Transplantation Versus Conventional Care for Relapsed/Refractory AML.
Efficient combinatorial adaptor-mediated targeting of acute myeloid leukemia with CAR T-cells.
Bone Marrow Stromal Cells Enhance Differentiation of Acute Myeloid Leukemia Induced by Pyrimidine Synthesis Inhibitors.
Epigenetic modifications in hematopoietic ecosystem: a key tuner from homeostasis to acute myeloid leukemia.
Glutaminase inhibition in combination with azacytidine in myelodysplastic syndromes: a phase 1b/2 clinical trial and correlative analyses.
CBL mutations in chronic myelomonocytic leukemia often occur in the RING domain with multiple subclones per patient: Implications for targeting.
Haematological features of telomere biology disorders diagnosed in adulthood: A French nationwide study of 127 patients.
Knowledge graphs facilitate prediction of drug response for acute myeloid leukemia.
HDAC7 is a potential therapeutic target in acute erythroid leukemia.
Proteasome inhibition enhances the anti-leukemic efficacy of chimeric antigen receptor (CAR) expressing NK cells against acute myeloid leukemia.
UM171 enhances fitness and engraftment of gene modified hematopoietic stem cells from sickle cells disease patients.
Multiomic single cell sequencing identifies stemlike nature of mixed phenotype acute leukemia.
Clonal Hematopoiesis and Clinical Outcomes in Metastatic Castration-Resistant Prostate Cancer Patients Given Androgen Receptor Pathway Inhibitors (Alliance A031201).
Lipoprotein metabolism mediates hematopoietic stem cell responses under acute anemic conditions.
Current status and research directions in acute myeloid leukemia.
Phase I/II study of the clinical activity and safety of GSK3326595 in patients with myeloid neoplasms.
Pharmacological restriction of genomic binding sites redirects PU.1 pioneer transcription factor activity.
Drug-resistant menin variants retain high binding affinity and interactions with MLL1.
Therapy-related AML: long-term outcome in a large cohort of AML-patients with intensive and non-intensive therapy.
Leucocytosis during induction therapy with all-trans-retinoic acid and arsenic trioxide in acute promyelocytic leukaemia predicts differentiation syndrome and treatment-related complications.
Risk of Bleeding in Essential Thrombocythemia Patients with Extreme Thrombocytosis.
CCR2 cooperativity promotes hematopoietic stem cell homing to the bone marrow.

J Clin Oncol. 2024 Sep 16. JCO2400235

Single or Double Induction With 7 + 3 Containing Standard or High-Dose Daunorubicin for Newly Diagnosed AML: The Randomized DaunoDouble Trial by the Study Alliance Leukemia.

Christoph Röllig, Björn Steffen, Christoph Schliemann, Jan-Henrik Mikesch, Nael Alakel, Regina Herbst, Mathias Hänel, Richard Noppeney, Maher Hanoun, Martin Kaufmann, Barbora Weinbergerova, Kerstin Schäfer-Eckart, Tim Sauer, Andreas Neubauer, Andreas Burchert, Claudia D Baldus, Jolana Mertová, Edgar Jost, Dirk Niemann, Jan Novák, Stefan W Krause, Sebastian Scholl, Andreas Hochhaus, Gerhard Held, Tomas Szotkowski, Andreas Rank, Christoph Schmid, Lars Fransecky, Sabine Kayser, Markus Schaich, Michael Kramer, Frank Fiebig, Annett Haake, Johannes Schetelig, Jan Moritz Middeke, Friedrich Stölzel, Uwe Platzbecker, Christian Thiede, Carsten Müller-Tidow, Wolfgang E Berdel, Gerhard Ehninger, Jiri Mayer, Hubert Serve, Martin Bornhäuser.

PURPOSE: To determine the optimal daunorubicin dose and number of 7 + 3 induction cycles in newly diagnosed AML, this randomized controlled trial compared a once daily dose of 60 mg/m2 with 90 mg/m2 daunorubicin in the first 7 + 3 induction and one versus two cycles of 7 + 3 induction.PATIENTS AND METHODS: Patients age 18-65 years with newly diagnosed AML were randomly assigned to 60 versus 90 mg/m2 daunorubicin once daily plus cytarabine. Patients with marrow blasts below 5% on day 15 after first induction were randomly assigned to receive a second induction cycle or no second induction cycle.
RESULTS: Eight hundred and sixty-four patients with a median age of 52 years were randomly assigned. After a preplanned interim analysis showing no significant difference in response between 60 and 90 mg/m2, all consecutive patients received 60 mg/m2 daunorubicin once daily. The proportion of good early responders was 44% versus 48% (P = .983) with a composite complete remission (CRc) rate of 90% versus 89% after induction (P = .691); the 3-year relapse-free survival (RFS) after 60 versus 90 mg/m2 once daily was 54% versus 50% (P = .561), and the 3-year overall survival (OS) was 65% versus 58% (P = .242). Among 389 good responders, CRc rates at the end of induction were 87% after single induction and 85% after double induction. The 3-year RFS was 51% versus 60% (hazard ratio [HR], 1.3; P = .091), and the 3-year OS was 76% versus 75% after single versus double induction (HR, 1.0; P = .937).
CONCLUSION: The use of 90 mg/m2 daunorubicin once daily in the context of classical 7 + 3 induction does not significantly improve early response and does not lead to higher remission rates or longer survival than 60 mg/m2 once daily. In patients with a good early response after first induction, a second induction has only a limited impact on RFS and does not result in an OS benefit.

DOI: https://doi.org/10.1200/JCO.24.00235
Leukemia. 2024 Sep 17.

Impact of BCR::ABL1 single nucleotide variants on asciminib efficacy.

Andrew J Innes, Chloe Hayden, Victoria Orovboni, Simone Claudiani, Fiona Fernando, Afzal Khan, David Rees, Jennifer Byrne, Paolo Gallipoli, Sebastian Francis, Mhairi Copland, Gillian Horne, Manoj Raghavan, Claire Arnold, Angela Collins, Tanya Cranfield, Nicholas Cunningham, Akila Danga, Peter Forsyth, Rebecca Frewin, Paula Garland, Guy Hannah, Daniele Avenoso, Sandra Hassan, Brian J P Huntly, Jissan Husain, Sudhakaran Makkuni, Kate Rothwell, Jamshid Khorashad, Jane F Apperley, Dragana Milojkovic.

Asciminib is a potent and selective inhibitor of BCR::ABL1, with potential to avoid toxicity resulting from off-target kinase inhibition. Forty-nine patients treated with asciminib under a managed access program in the UK were evaluated for toxicity and response. Intolerance, rather than resistance (65% vs. 35%), was the most common reason for cessation of the last-line of treatment but asciminib was well tolerated, with most patients (29, 59%) remaining on treatment at a median of 14 months follow-up, and only 6 (12%) stopping for intolerance. Of 44 patients assessable for response, 29 (66%) achieved a complete cytogenetic response (CCyR) or better, with poorer responses seen in those stopping their last-line of therapy for resistance. Fewer patients with a prior history of a non-T315I-BCR::ABL1 single nucleotide variant (BSNV), or a non-T315I-BSNV detectable at baseline achieved CCyR. Serial tracking of BSNV by next generation sequencing demonstrated clonal expansion of BSNV-harbouring populations, which in some settings was associated with resistance (E459K, F317L, F359I), while in others was seen in the context of ongoing response, often with intensified dosing (T315I, I502F). These data suggest that asciminib exerts selective pressure on some BSNV-harbouring populations in vivo, some of which may respond to intensified dosing.

DOI: https://doi.org/10.1038/s41375-024-02411-7
Leukemia. 2024 Sep 17.

Selective degradation of mutant FMS-like tyrosine kinase-3 requires BIM-dependent depletion of heat shock proteins.

Melisa Halilovic, Mohamed Abdelsalam, Joanna Zabkiewicz, Michelle Lazenby, Caroline Alvares, Matthias Schmidt, Walburgis Brenner, Sara Najafi, Ina Oehme, Christoph Hieber, Yanira Zeyn, Matthias Bros, Wolfgang Sippl, Oliver H Krämer.

Internal tandem duplications in the FMS-like tyrosine kinase-3 (FLT3-ITD) are common mutations in acute myeloid leukemia (AML). Proteolysis-targeting chimeras (PROTACs) that induce proteasomal degradation of mutated FLT3 emerge as innovative pharmacological approach. Molecular mechanisms that control targeted proteolysis beyond the ubiquitin-proteasome-system are undefined and PROTACs are the only known type of FLT3 degraders. We report that the von-Hippel-Lindau ubiquitin-ligase based FLT3 PROTAC MA49 (melotinib-49) and the FLT3 hydrophobic tagging molecule MA50 (halotinib-50) reduce endoplasmic reticulum-associated, oncogenic FLT3-ITD but spare FLT3. Nanomolar doses of MA49 and MA50 induce apoptosis of human leukemic cell lines and primary AML blasts with FLT3-ITD (p < 0.05-0.0001), but not of primary hematopoietic stem cells and differentiated immune cells, FLT3 wild-type cells, retinal cells, and c-KIT-dependent cells. In vivo activity of MA49 against FLT3-ITD-positive leukemia cells is verified in a Danio rerio model. The degrader-induced loss of FLT3-ITD involves the pro-apoptotic BH3-only protein BIM and a previously unidentified degrader-induced depletion of protein-folding chaperones. The expression levels of HSP90 and HSP110 correlate with reduced AML patient survival (p < 0.1) and HSP90, HSP110, and BIM are linked to the expression of FLT3 in primary AML cells (p < 0.01). HSP90 suppresses degrader-induced FLT3-ITD elimination and thereby establishes a mechanistically defined feed-back circuit.

DOI: https://doi.org/10.1038/s41375-024-02405-5
Blood Adv. 2024 Sep 18. pii: bloodadvances.2024013086. [Epub ahead of print]

Venetoclax-based salvage therapy as bridge-to-transplant is feasible and effective in patients with relapsed/refractory AML.

Julia Marie Unglaub, Richard F Schlenk, Jan M Middeke, Stefan W Krause, Sabrina Kraus, Hermann Einsele, Michael Kramer, Sven Zukunft, Joseph Kauer, Simon Renders, Elena Katelari, Christoph Schliemann, Caroline Pabst, Thomas Luft, Peter Dreger, Christoph Röllig, Martin Bornhäuser, Carsten Müller-Tidow, Tim Sauer.

The BCL2-inhibitor Venetoclax (VEN) in combination with hypomethylating agents (HMA) has been approved for first-line treatment of acute myeloid leukemai (AML) patients ineligible for intensive treatment. Emerging Data suggest that VEN containing treatment strategies may also be effective in relapsed/refractory (R/R) AML, however, comparative studies with conventional treatment strategies for medically fit patients as a bridge-to transplant strategy are limited. Using propensity score matching (PSM) analysis, we compared 37 R/R AML patients, who received VEN-based salvage therapy as bridge to allogeneic hematopoietic cell transplantation (allo-HCT) with 90 patients from the German Study Alliance Leukemia (SAL) AML registry, who were treated with non-VEN-containing salvage therapy according to their treating physician's choice (TPC) including intensive and non-intensive protocols. The overall response rate (ORR=CR+CRi) among all VEN patients was significantly higher compared to the TPC control cohort (62% vs. 42%; p=0.049). Overall, 73% of VEN-treated patients vs. 63% of TPC patients were successfully bridged to allo-HCT (p =0.41). After a median follow-up of 34.3 months for the VEN cohort and 21.0 months for the TPC cohort, the median overall-survival (OS) was 15.8 months (95%-CI, 10.6-NE) and 10.5 months (95%-CI, 6.8-19.6) (p=0.15), respectively. PSM revealed a trend towards improved OS for VEN patients (HR 0.70; 95%-CI, 0.41-1.22; p=0.20). Median event free survival (EFS) was significantly longer in the VEN cohort (8.0 months) compared to the TPC cohort (3.7 months) (p=0.006). In summary, our data suggests that VEN-based salvage therapy is a safe and effective bridge to allo-HCT for this difficult-to-treat AML patient population.

DOI: https://doi.org/10.1182/bloodadvances.2024013086
Leuk Res. 2024 Sep 06. pii: S0145-2126(24)00143-7. [Epub ahead of print]146 107577

Outcomes of patients with acute myeloid leukemia treated with intensive therapy after failure of venetoclax-inclusive, less-intensive therapy.

Rohan K Achar, Benjamin J McCormick, Emily Dworkin, Emily M Geramita, Annie Im, Anand A Patel, Talha Badar, Rory M Shallis.



Keywords:  AML; Acute myeloid leukemia; Refractory; Relapsed; Salvage; Venetoclax

DOI:  https://doi.org/10.1016/j.leukres.2024.107577
EBioMedicine. 2024 Sep 17. pii: S2352-3964(24)00352-9. [Epub ahead of print]108 105316

Phosphoproteomics predict response to midostaurin plus chemotherapy in independent cohorts of FLT3-mutated acute myeloid leukaemia.

Weronika E Borek, Luis Nobre, S Federico Pedicona, Amy E Campbell, Josie A Christopher, Nazrath Nawaz, David N Perkins, Pedro Moreno-Cardoso, Janet Kelsall, Harriet R Ferguson, Bela Patel, Paolo Gallipoli, Andrea Arruda, Alex J Ambinder, Andrew Thompson, Andrew Williamson, Gabriel Ghiaur, Mark D Minden, John G Gribben, David J Britton, Pedro R Cutillas, Arran D Dokal.

  BACKGROUND: Acute myeloid leukaemia (AML) is a bone marrow malignancy with poor prognosis. One of several treatments for AML is midostaurin combined with intensive chemotherapy (MIC), currently approved for FLT3 mutation-positive (FLT3-MP) AML. However, many patients carrying FLT3 mutations are refractory or experience an early relapse following MIC treatment, and might benefit more from receiving a different treatment. Development of a stratification method that outperforms FLT3 mutational status in predicting MIC response would thus benefit a large number of patients.METHODS: We employed mass spectrometry phosphoproteomics to analyse 71 diagnosis samples of 47 patients with FLT3-MP AML who subsequently received MIC. We then used machine learning to identify biomarkers of response to MIC, and validated the resulting predictive model in two independent validation cohorts (n = 20).
FINDINGS: We identified three distinct phosphoproteomic AML subtypes amongst long-term survivors. The subtypes showed similar duration of MIC response, but different modulation of AML-implicated pathways, and exhibited distinct, highly-predictive biomarkers of MIC response. Using these biomarkers, we built a phosphoproteomics-based predictive model of MIC response, which we called MPhos. When applied to two retrospective real-world patient test cohorts (n = 20), MPhos predicted MIC response with 83% sensitivity and 100% specificity (log-rank p < 7∗10-5, HR = 0.005 [95% CI: 0-0.31]).
INTERPRETATION: In validation, MPhos outperformed the currently-used FLT3-based stratification method. Our findings have the potential to transform clinical decision-making, and highlight the important role that phosphoproteomics is destined to play in precision oncology.
FUNDING: This work was funded by Innovate UK grants (application numbers: 22217 and 10054602) and by Kinomica Ltd.

Keywords:  Acute myeloid leukaemia; Drug response prediction; Machine learning; Midostaurin plus chemotherapy; Phosphoproteomics; Precision medicine

DOI:  https://doi.org/10.1016/j.ebiom.2024.105316
J Clin Oncol. 2024 Sep 19. JCO2302018

Randomized Phase III SIERRA Trial of 131I-Apamistamab Before Allogeneic Hematopoietic Cell Transplantation Versus Conventional Care for Relapsed/Refractory AML.

Boglarka Gyurkocza, Rajneesh Nath, Stuart Seropian, Hannah Choe, Mark R Litzow, Camille Abboud, Nebu Koshy, Patrick Stiff, Benjamin Tomlinson, Sunil Abhyankar, James Foran, Parameswaran Hari, George Chen, Zaid Al-Kadhimi, Partow Kebriaei, Mitchell Sabloff, Johnnie J Orozco, Katarzyna Jamieson, Margarida Silverman, Koen Van Besien, Michael Schuster, Arjun Datt Law, Karilyn Larkin, Neeta Pandit-Taskar, Scott D Rowley, Pashna Munshi, Rachel Cook, Moshe Y Levy, Hillard M Lazarus, Brenda M Sandmaier, John M Pagel, Vijay Reddy, James MacDougall, Kathleen McNamara, Jennifer Spross, Elaina Haeuber, Madhuri Vusirikala, Akash Nahar, Avinash Desai, Sergio Giralt.

PURPOSE: Older patients with relapsed or refractory AML (RR AML) have dismal prognoses without allogeneic hematopoietic cell transplantation (alloHCT). SIERRA compared a targeted pretransplant regimen involving the anti-CD45 radioconjugate 131I-apamistamab with conventional care.METHODS: SIERRA (ClinicalTrials.gov identifier: NCT02665065) was a phase III open-label trial. Patients age ≥55 years with active RR AML were randomly assigned 1:1 to either an 131I-apamistamab-led regimen before alloHCT or conventional care followed by alloHCT if initial complete remission (CR)/CR with incomplete platelet recovery (CRp) occurred. Initial response was assessed 28-56 days after alloHCT in the 131I-apamistamab group and 28-42 days after salvage chemotherapy initiation; patients without CR/CRp or with AML progression could cross over to receive 131I-apamistamab followed by alloHCT. The primary end point was durable complete remission (dCR) lasting 180 days after initial CR/CRp. Secondary end points were overall survival (OS) and event-free survival (EFS), assessed hierarchically in the intention-to-treat (ITT) population.
RESULTS: The ITT population included 153 patients (131I-apamistamab [n = 76]; conventional care [n = 77]). In total, 44/77 conventional care arm patients crossed over and 40/77 (52%) received 131I-apamistamab and alloHCT, with six patients (13.6%) experiencing a dCR. In the ITT population, the dCR rate was significantly higher with 131I-apamistamab (17.1% [95% CI, 9.4 to 27.5]) than conventional care (0% [95% CI, 0 to 4.7]; P < .0001). The OS hazard ratio (HR) was 0.99 (95% CI, 0.70 to 1.41; P = .96), and the EFS HR was 0.23 (95% CI, 0.15 to 0.34), with HR <1 favoring 131I-apamistamab. Grade ≥3 treatment-related adverse events occurred in 59.7% and 59.2% of the 131I-apamistamab and conventional care groups, respectively.
CONCLUSION: The 131I-apamistamab-led regimen was associated with a higher dCR rate than conventional care in older patients with RR AML. 131I-apamistamab was well tolerated and could address an unmet need in this population.

DOI: https://doi.org/10.1200/JCO.23.02018
Leukemia. 2024 Sep 18.

Efficient combinatorial adaptor-mediated targeting of acute myeloid leukemia with CAR T-cells.

Laura Volta, Renier Myburgh, Christian Pellegrino, Christian Koch, Monique Maurer, Francesco Manfredi, Mara Hofstetter, Anne Kaiser, Florin Schneiter, Jan Müller, Marco M Buehler, Roberto De Luca, Nicholas Favalli, Chiara F Magnani, Timm Schroeder, Dario Neri, Markus G Manz.

CAR T-cell products targeting lineage-specific cell-of-origin antigens, thereby eliminating both tumor and healthy counterpart cells, are currently clinically approved therapeutics in B- and plasma-cell malignancies. While they represent a major clinical improvement, they are still limited in terms of efficacy by e.g. single, sometimes low-expressed antigen targeting, and in terms of safety by e.g., lack of on-off activity. Successful cell-of-origin non-discriminative targeting of heterogeneous hematopoietic stem and progenitor cell malignancies, such as acute myeloid leukemia (AML), will require antigen-versatile targeting and off-switching of effectors in order to then allow rescue by hematopoietic stem cell transplantation (HSCT), preventing permanent myeloablation. To address this, we developed adaptor-CAR (AdFITC-CAR) T-cells targeting fluoresceinated AML antigen-binding diabody adaptors. This platform enables the use of adaptors matching the AML-antigen-expression profile and conditional activity modulation. Combining adaptors significantly improved lysis of AML cells in vitro. In therapeutic xenogeneic mouse models, AdFITC-CAR T-cells co-administered with single diabody adaptors were as efficient as direct CAR T-cells, and combinatorial use of adaptors further enhanced therapeutic efficacy against both, cell lines and primary AML. Collectively, this study provides proof-of-concept that AdFITC-CAR T-cells and combinations of adaptors can efficiently enhance immune-targeting of AML.

DOI: https://doi.org/10.1038/s41375-024-02409-1
Am J Physiol Cell Physiol. 2024 Sep 16.

Bone Marrow Stromal Cells Enhance Differentiation of Acute Myeloid Leukemia Induced by Pyrimidine Synthesis Inhibitors.

Tomislav Smoljo, Hrvoje Lalic, Vilma Dembitz, Barbara Tomic, Josip Batinic, Radovan Vrhovac, Antonio Bedalov, Dora Visnjic.

  Acute myeloid leukemia (AML) is a heterogeneous group of hematologic malignancies characterized by differentiation arrest, high relapse rates, and poor survival. The bone marrow (BM) microenvironment is recognized as a critical mediator of drug resistance and a primary site responsible for AML relapse. Our previous study reported that 5-aminoimidazole-4-carboxamide ribonucleoside (AICAr) induces AML cell differentiation by inhibiting pyrimidine synthesis and activating Checkpoint kinase 1. While the protective effect of BM stroma on leukemia cells in response to cytotoxic drugs is well-documented, its effect on AML differentiation remains less explored. In this study, we investigated the impact of stromal cell lines and primary mesenchymal stromal cells (MSCs) on AML cell line differentiation triggered by AICAr and brequinar, a known dihydroorotate dehydrogenase (DHODH) inhibitor. Our findings indicate that the mouse MS-5 stromal cell line, known for its cytoprotective effects, does not inhibit AML cell differentiation induced by pyrimidine synthesis inhibitors. Interestingly, AICAr caused morphological changes and growth arrest in MS-5 stromal cells via an AMPK-dependent pathway. Human stromal cell lines HS-5 and HS-27, as well as primary MSCs isolated from patient bone marrow, were superior in promoting AML differentiation compared to mouse cells in response to AICAr and brequinar, with the inhibitors not significantly affecting the stromal cells themselves. In conclusion, our study highlights the supportive role of human BM MSCs in enhancing the differentiation effects of pyrimidine synthesis inhibitors on AML cells, suggesting that AML treatment strategies focusing on differentiation rather than cell killing may be successful in clinical settings.

Keywords:  AICAr; acute myeloid leukemia; bone marrow stromal cells; brequinar; differentiation

DOI:  https://doi.org/10.1152/ajpcell.00413.2024
Blood Sci. 2024 Oct;6(4): e00206

Epigenetic modifications in hematopoietic ecosystem: a key tuner from homeostasis to acute myeloid leukemia.

Shuxin Yao, Rongxia Guo, Wen Tian, Yanbing Zheng, Jin Hu, Guoqiang Han, Rong Yin, Fuling Zhou, Haojian Zhang.

  Hematopoietic stem cells (HSCs) maintain homeostasis in the hematopoietic ecosystem, which is tightly regulated at multiple layers. Acute myeloid leukemia (AML) is a severe hematologic malignancy driven by genetic and epigenetic changes that lead to the transformation of leukemia stem cells (LSCs). Since somatic mutations in DNA methylation-related genes frequently occur in AML, DNA methylation is widely altered and functions as a starting engine for initiating AML. Additionally, RNA modifications, especially N6-methyladenosine (m6A), also play an important role in the generation and maintenance of the hematopoietic ecosystem, and AML development requires reprogramming of m6A modifications to facilitate cells with hallmarks of cancer. Given the complex pathogenesis and poor prognosis of AML, it is important to fully understand its pathogenesis. Here, we mainly focus on DNA methylation and RNA m6A modification in hematopoiesis and AML and summarize recent advances in this field.

Keywords:  Acute myeloid leukemia; DNA methylation; Hematopoiesis; Hematopoietic stem cells; Leukemia stem cells; RNA modification

DOI:  https://doi.org/10.1097/BS9.0000000000000206
Nat Cancer. 2024 Sep 19.

Glutaminase inhibition in combination with azacytidine in myelodysplastic syndromes: a phase 1b/2 clinical trial and correlative analyses.

Courtney D DiNardo, Divij Verma, Natalia Baran, Tushar D Bhagat, Anna Skwarska, Alessia Lodi, Kapil Saxena, Tianyu Cai, Xiaoping Su, Veronica A Guerra, Gowri Poigaialwar, Vinitha M Kuruvilla, Sergej Konoplev, Shanisha Gordon-Mitchell, Kith Pradhan, Srinivas Aluri, G Lavender Hackman, Sovira Chaudhry, Meghan Collins, Shannon R Sweeney, Jonathan Busquets, Atul Singh Rathore, Qing Deng, Michael R Green, Steven Grant, Susan Demo, Gaurav S Choudhary, Srabani Sahu, Beamon Agarwal, Mason Spodek, Victor Thiruthuvanathan, Britta Will, Ulrich Steidl, George D Tippett, Jan Burger, Gautam Borthakur, Elias Jabbour, Naveen Pemmaraju, Tapan Kadia, Steven Kornblau, Naval G Daver, Kiran Naqvi, Nicholas J Short, Guillermo Garcia-Manero, Stefano Tiziani, Amit Verma, Marina Konopleva.

Malignancies are reliant on glutamine as an energy source and a facilitator of aberrant DNA methylation. We demonstrate preclinical synergy of telaglenastat (CB-839), a selective glutaminase inhibitor, combined with azacytidine (AZA), followed by a single-arm, open-label, phase 1b/2 study in persons with advanced myelodysplastic syndrome (MDS). The dual primary endpoints evaluated clinical activity, safety and tolerability; secondary endpoints evaluated pharmacokinetics, pharmacodynamics, overall survival, event-free survival and duration of response. The dose-escalation study included six participants and the dose-expansion study included 24 participants. Therapy was well tolerated and led to an objective response rate of 70% with (marrow) complete remission in 53% of participants and a median overall survival of 11.6 months, with evidence of myeloid differentiation in responders determined by single-cell RNA sequencing. Glutamine transporter solute carrier family 38 member 1 in MDS stem cells was associated with clinical responses and predictive of worse prognosis in a large MDS cohort. These data demonstrate the safety and efficacy of CB-839 and AZA as a combined metabolic and epigenetic approach in MDS. ClinicalTrials.gov identifier: NCT03047993 .

DOI: https://doi.org/10.1038/s43018-024-00811-3
PLoS One. 2024 ;19(9): e0310641

CBL mutations in chronic myelomonocytic leukemia often occur in the RING domain with multiple subclones per patient: Implications for targeting.

Kelly Lim, Winnie L Kan, Pramod C Nair, Monika Kutyna, Angel F Lopez, Timothy Hercus, David M Ross, Steven Lane, Chun Yew Fong, Anna Brown, Agnes Yong, David Yeung, Timothy Hughes, Devendra Hiwase, Daniel Thomas.

Chronic myelomonocytic leukemia (CMML) is a rare blood cancer of older adults (3 in every 1,000,000 persons) characterized by poor survival and lacking effective mutation-specific therapy. Mutations in the ubiquitin ligase Cbl occur frequently in CMML and share biological and molecular features with a clonal disease occurring in children, juvenile myelomonocytic leukemia (JMML). Here we analyzed the clinical presentations, molecular features and immunophenotype of CMML patients with CBL mutations enrolled in a prospective Phase II clinical trial stratified according to molecular markers. Clinically, CBL mutations were associated with increased bone marrow blasts at diagnosis, leukocytosis and splenomegaly, similar to patients harboring NRAS or KRAS mutations. Interestingly, 64% of patients presented with more than one CBL variant implying a complex subclonal architecture, often with co-occurrence of TET2 mutations. We found CBL mutations in CMML frequently clustered in the RING domain in contrast to JMML, where mutations frequently involve the linker helix region (P<0.0001). According to our comparative alignment of available X-ray structures, mutations in the linker helix region such as Y371E give rise to conformational differences that could be exploited by targeted therapy approaches. Furthermore, we noted an increased percentage of CMML CD34+ stem and progenitor cells expressing CD116 and CD131 in all CBL mutant cases and increased CD116 receptor density compared to healthy controls, similar to CMML overall. In summary, our data demonstrate that CBL mutations are associated with distinct molecular and clinical features in CMML and are potentially targetable with CD116-directed immunotherapy.

DOI: https://doi.org/10.1371/journal.pone.0310641
Br J Haematol. 2024 Sep 15.

Haematological features of telomere biology disorders diagnosed in adulthood: A French nationwide study of 127 patients.

François Maillet, Jacques-Emmanuel Galimard, Raphaël Borie, Elodie Lainey, Lise Larcher, Marie Passet, Aurélie Plessier, Thierry Leblanc, Louis Terriou, Delphine Lebon, Vincent Alcazer, Pascal Cathebras, Michael Loschi, Abou-Chahla Wadih, Ambroise Marcais, Alice Marceau-Renaut, Nathalie Couque, Bruno Lioure, Jean Soulier, Ibrahima Ba, Gérard Socié, Regis Peffault de Latour, Caroline Kannengiesser, Flore Sicre de Fontbrune.

  Data on haematological features of telomere biology disorders (TBD) remain scarce. We describe haematological, extra-haematological characteristics and prognosis of 127 genetically confirmed TBD patients diagnosed after the age of 15. Ninety-three index cases and 34 affected relatives were included. At diagnosis of TBD, 76.3% of index cases had haematological features, half pulmonary features and a third liver features. At diagnosis, bone marrow failure (BMF) was present in 59 (46.5%), myelodysplastic syndrome (MDS) in 22 (17.3%) and acute myeloid leukaemia (AML) in 2 (1.6%) while 13 (10.2%) developed or worsened bone marrow involvement during follow-up. At diagnosis, compared to MDS/AML patients, BMF patients were younger (median 23.1 years vs. 43.8, p = 0.007), and had a better outcome (4-year overall survival 76.3% vs. 31.8%, p < 0.001). While frequencies and burden of cytogenetical and somatic mutations increased significantly in myeloid malignancies, some abnormalities were also observed in patients with normal blood counts and BMF, notably somatic spliceosome variants. Solid cancers developed in 8.7% patients, mainly human papillomavirus-related cancers and hepatocellular carcinomas. TBD is a multiorgan progressive disease. While BMF is the main haematological disorder, high-risk myeloid malignancies are common, and are, together with age, the only factors associated with a worse outcome.

Keywords:  acute myeloid leukaemia; bone marrow failure; myelodysplastic syndrome; telomere biology disorders

DOI:  https://doi.org/10.1111/bjh.19767
iScience. 2024 Sep 20. 27(9): 110755

Knowledge graphs facilitate prediction of drug response for acute myeloid leukemia.

Guangrong Qin, Yue Zhang, Jeffrey W Tyner, Christopher J Kemp, Ilya Shmulevich.

  Acute myeloid leukemia (AML) is a highly aggressive and heterogeneous disease, underscoring the need for improved therapeutic options and methods to optimally predict responses. With the wealth of available data resources, including clinical features, multiomics analysis, and ex vivo drug screening from AML patients, development of drug response prediction models has become feasible. Knowledge graphs (KGs) embed the relationships between different entities or features, allowing for explanation of a wide breadth of drug sensitivity and resistance mechanisms. We designed AML drug response prediction models guided by KGs. Our models included engineered features, relative gene expression between marker genes for each drug and regulators (e.g., transcription factors). We identified relative gene expression of FGD4-MIR4519, NPC2-GATA2, and BCL2-NFKB2 as predictive features for venetoclax ex vivo drug response. The KG-guided models provided high accuracy in independent test sets, overcame potential platform batch effects, and provided candidate drug sensitivity biomarkers for further validation.

Keywords:  Bioinformatics; Biological sciences; Cancer

DOI:  https://doi.org/10.1016/j.isci.2024.110755
Leukemia. 2024 Sep 15.

HDAC7 is a potential therapeutic target in acute erythroid leukemia.

Wenyu Zhang, Keita Yamamoto, Yu-Hsuan Chang, Tomohiro Yabushita, Yangying Hao, Ruka Shimura, Jakushin Nakahara, Shiori Shikata, Kohei Iida, Qianyi Chen, Xichen Zhang, Toshio Kitamura, Susumu Goyama.

Acute erythroleukemia (AEL) is a rare subtype of acute myeloid leukemia with a poor prognosis. In this study, we established a novel murine AEL model with Trp53 depletion and ERG overexpression. ERG overexpression in Trp53-deficient mouse bone marrow cells, but not in wild-type bone marrow cells, leads to AEL development within two months after transplantation with 100% penetrance. The established mouse AEL cells expressing Cas9 can be cultured in vitro, induce AEL in vivo even in unirradiated recipient mice, and enable efficient gene ablation using the CRISPR/Cas9 system. We also confirmed the cooperation between ERG overexpression and TP53 inactivation in promoting the growth of immature erythroid cells in human cord blood cells. Mechanistically, ERG antagonizes KLF1 and inhibits erythroid maturation, whereas TP53 deficiency promotes proliferation of erythroid progenitors. Furthermore, we identified HDAC7 as a specific susceptibility in AEL by the DepMap-based two-group comparison analysis. HDAC7 promotes the growth of human and mouse AEL cells both in vitro and in vivo through its non-enzymatic functions. Our study provides experimental evidence that TP53 deficiency and ERG overexpression are necessary and sufficient for the development of AEL and highlights HDAC7 as a promising therapeutic target for this disease.

DOI: https://doi.org/10.1038/s41375-024-02394-5
J Hematol Oncol. 2024 Sep 16. 17(1): 85

Proteasome inhibition enhances the anti-leukemic efficacy of chimeric antigen receptor (CAR) expressing NK cells against acute myeloid leukemia.

David Sedloev, Qian Chen, Julia M Unglaub, Nicola Schanda, Yao Hao, Eleni Besiridou, Brigitte Neuber, Anita Schmitt, Simon Raffel, Yi Liu, Maike Janssen, Carsten Müller-Tidow, Michael Schmitt, Tim Sauer.

BACKGROUND: Relapsed and refractory acute myeloid leukemia (AML) carries a dismal prognosis. CAR T cells have shown limited efficacy in AML, partially due to dysfunctional autologous T cells and the extended time for generation of patient specific CAR T cells. Allogeneic NK cell therapy is a promising alternative, but strategies to enhance efficacy and persistence may be necessary. Proteasome inhibitors (PI) induce changes in the surface proteome which may render malignant cells more vulnerable to NK mediated cytotoxicity. Here, we investigated the potential benefit of combining PIs with CAR-expressing allogeneic NK cells against AML.METHODS: We established the IC50 concentrations for Bortezomib and Carfilzomib against several AML cell lines. Surface expression of class-I HLA molecules and stress-associated proteins upon treatment with proteasome inhibitors was determined by multiparameter flow cytometry. Using functional in vitro assays, we explored the therapeutic synergy between pre-treatment with PIs and the anti-leukemic efficacy of NK cells with or without expression of AML-specific CAR constructs against AML cell lines and primary patient samples. Also, we investigated the tolerability and efficacy of a single PI application strategy followed by (CAR-) NK cell infusion in two different murine xenograft models of AML.
RESULTS: AML cell lines and primary AML patient samples were susceptible to Bortezomib and Carfilzomib mediated cytotoxicity. Conditioned resistance to Azacitidine/Venetoclax did not confer primary resistance to PIs. Treating AML cells with PIs reduced the surface expression of class-I HLA molecules on AML cells in a time-and-dose dependent manner. Stress-associated proteins were upregulated on the transcriptional level and on the cell surface. NK cell mediated killing of AML cells was enhanced in a synergistic manner. PI pre-treatment increased effector-target cell conjugate formation and Interferon-γ secretion, resulting in enhanced NK cell activity against AML cell lines and primary samples in vitro. Expression of CD33- and CD70-specific CARs further improved the antileukemic efficacy. In vivo, Bortezomib pre-treatment followed by CAR-NK cell infusion reduced AML growth, leading to prolonged overall survival.
CONCLUSIONS: PIs enhance the anti-leukemic efficacy of CAR-expressing allogeneic NK cells against AML in vitro and in vivo, warranting further exploration of this combinatorial treatment within early phase clinical trials.

DOI: https://doi.org/10.1186/s13045-024-01604-y
Blood Adv. 2024 Sep 18. pii: bloodadvances.2024013932. [Epub ahead of print]

UM171 enhances fitness and engraftment of gene modified hematopoietic stem cells from sickle cells disease patients.

Boya Liu, Denise Klatt, Yu Zhou, John P Manis, Guy Sauvageau, Danilo Pellin, Christian Brendel, David A Williams.

Hematopoietic stem cell transplantation with lentiviral vector (LVV) transduced autologous cells has proven an effective therapeutic strategy for sickle cell disease (SCD). However, ex vivo culture or proliferative stress associated with in vivo reconstitution may amplify any underlying genetic risk of leukemia. We aimed to minimize culture-induced stress and reduce genomic damage during ex vivo culture, enhance stem cell fitness and reconstitution of SCD CD34+ cells transduced with BCL11A shmiR-encoding LVV currently in clinical trials (NCT NCT03282656). UM171, a pyrimidoindole derivative can expand normal hematopoietic stem cells (HSCs) during in vitro culture and has been shown to be safe and effective in clinical trials using umbilical cord blood (NCT02668315). We examined the effect of UM171 during ex vivo LVV transduction of SCD HSCs. Culture of SCD CD34+ HSCs with UM171 during transduction reduced DNA damage and reactive oxygen species (ROS), decreased apoptosis, and was associated with increased numbers of immunophenotypically defined long-term HSCs. UM171 increased the engraftment of LVV transduced human HSCs in immunodeficient mice and barcode tracing revealed increased clonal diversity of engrafting cells. In competitive transplantation assays, analysis of BM showed that cells transduced in the presence of UM171 consistently outcompeted those transduced under control conditions. In summary, exposure of SCD peripheral blood CD34+ cells to UM171 during LVV transduction enhances stem cell fitness. These findings suggest manufacturing of genetically modified HSCs in the presence of UM171 may improve efficacy, safety and sustainability of gene therapy utilizing ex vivo approaches.

DOI: https://doi.org/10.1182/bloodadvances.2024013932
Nat Commun. 2024 Sep 18. 15(1): 8191

Multiomic single cell sequencing identifies stemlike nature of mixed phenotype acute leukemia.

Cheryl A C Peretz, Vanessa E Kennedy, Anushka Walia, Cyrille L Delley, Andrew Koh, Elaine Tran, Iain C Clark, Corey E Hayford, Chris D'Amato, Yi Xue, Kristina M Fontanez, Aaron A May-Zhang, Trinity Smithers, Yigal Agam, Qian Wang, Hai-Ping Dai, Ritu Roy, Aaron C Logan, Alexander E Perl, Adam Abate, Adam Olshen, Catherine C Smith.

Despite recent work linking mixed phenotype acute leukemia (MPAL) to certain genetic lesions, specific driver mutations remain undefined for a significant proportion of patients and no genetic subtype is predictive of clinical outcomes. Moreover, therapeutic strategy for MPAL remains unclear, and prognosis is overall poor. We performed multiomic single cell profiling of 14 newly diagnosed adult MPAL patients to characterize the inter- and intra-tumoral transcriptional, immunophenotypic, and genetic landscapes of MPAL. We show that neither genetic profile nor transcriptome reliably correlate with specific MPAL immunophenotypes. Despite this, we find that MPAL blasts express a shared stem cell-like transcriptional profile indicative of high differentiation potential. Patients with the highest differentiation potential demonstrate inferior survival in our dataset. A gene set score, MPAL95, derived from genes highly enriched in the most stem-like MPAL cells, is applicable to bulk RNA sequencing data and is predictive of survival in an independent patient cohort, suggesting a potential strategy for clinical risk stratification.

DOI: https://doi.org/10.1038/s41467-024-52317-2
Clin Cancer Res. 2024 Sep 17. OF1-OF10

Clonal Hematopoiesis and Clinical Outcomes in Metastatic Castration-Resistant Prostate Cancer Patients Given Androgen Receptor Pathway Inhibitors (Alliance A031201).

Jeffrey L Jensen, Olivia Bobek, Irenaeus C C Chan, Brian C Miller, David W Hillman, Glenn Heller, Todd Druley, Andrew J Armstrong, Michael J Morris, Matthew I Milowsky, Himisha Beltran, Kelly L Bolton, Catherine C Coombs.

PURPOSE: Mutations in hematopoietic progenitor cells accumulate with age leading to clonal expansion, termed clonal hematopoiesis (CH). CH in the general population is associated with hematopoietic neoplasms and reduced overall survival (OS), predominantly through cardiovascular adverse events (CVAE). Because androgen receptor pathway inhibitors (ARPI) used in metastatic castration-resistant prostate cancer (mCRPC) are also associated with CVAEs and because CH negatively impacted survival in an advanced solid tumor cohort, we hypothesized that CH in mCRPC may be associated with increased CVAEs and inferior survival.EXPERIMENTAL DESIGN: A targeted DNA sequencing panel captured common CH mutations in pretreatment blood samples from 957 patients enrolled in Alliance A031201: a randomized trial of enzalutamide ± abiraterone/prednisone in the first-line mCRPC setting. The primary outcome was the impact of CH on OS; the secondary outcomes were progression-free survival (PFS) and CVAEs.
RESULTS: Baseline comorbidities were similar by CH status. No differences in OS/progression-free survival were detected regardless of treatment arm or the variant allele frequency threshold used to define CH [primary: 2% (normal-CH, N-CH); exploratory: 0.5% (low-CH) and 10% (high-CH, H-CH)]. Patients with H-CH (7.2%) and TET2-mutated N-CH (6.0%) had greater odds of any CVAE (14.5% vs. 4.0%; P = 0.0004 and 12.3% vs. 4.2%; P = 0.010, respectively). More major CVAEs were observed in patients with H-CH (5.8% vs. 1.9%; P = 0.042) and N-CH (3.4% vs. 1.8%; P = 0.147).
CONCLUSIONS: CH did not affect survival in patients with mCRPC treated with ARPIs in A031201. H-CH and TET2-mutated CH were associated with more CVAEs. These findings inform the risk/benefit discussion about ARPIs in mCRPC.

DOI: https://doi.org/10.1158/1078-0432.CCR-24-0803
Nat Commun. 2024 Sep 16. 15(1): 8131

Lipoprotein metabolism mediates hematopoietic stem cell responses under acute anemic conditions.

Kiyoka Saito, Mark van der Garde, Terumasa Umemoto, Natsumi Miharada, Julia Sjöberg, Valgardur Sigurdsson, Haruki Shirozu, Shunsuke Kamei, Visnja Radulovic, Mitsuyoshi Suzuki, Satoshi Nakano, Stefan Lang, Jenny Hansson, Martin L Olsson, Takashi Minami, Gunnar Gouras, Johan Flygare, Kenichi Miharada.

Hematopoietic stem cells (HSCs) react to various stress conditions. However, it is unclear whether and how HSCs respond to severe anemia. Here, we demonstrate that upon induction of acute anemia, HSCs rapidly proliferate and enhance their erythroid differentiation potential. In severe anemia, lipoprotein profiles largely change and the concentration of ApoE increases. In HSCs, transcription levels of lipid metabolism-related genes, such as very low-density lipoprotein receptor (Vldlr), are upregulated. Stimulation of HSCs with ApoE enhances their erythroid potential, whereas HSCs in Apoe knockout mice do not respond to anemia induction. VldlrhighHSCs show higher erythroid potential, which is enhanced after acute anemia induction. VldlrhighHSCs are epigenetically distinct because of their low chromatin accessibility, and more chromatin regions are closed upon acute anemia induction. Chromatin regions closed upon acute anemia induction are mainly binding sites of Erg. Inhibition of Erg enhanced the erythroid differentiation potential of HSCs. Our findings indicate that lipoprotein metabolism plays an important role in HSC regulation under severe anemic conditions.

DOI: https://doi.org/10.1038/s41467-024-52509-w
Blood Cancer J. 2024 Sep 19. 14(1): 163

Current status and research directions in acute myeloid leukemia.

Hagop Kantarjian, Gautam Borthakur, Naval Daver, Courtney D DiNardo, Ghayas Issa, Elias Jabbour, Tapan Kadia, Koji Sasaki, Nicholas J Short, Musa Yilmaz, Farhad Ravandi.

The understanding of the molecular pathobiology of acute myeloid leukemia (AML) has spurred the identification of therapeutic targets and the development of corresponding novel targeted therapies. Since 2017, twelve agents have been approved for the treatment of AML subsets: the BCL2 inhibitor venetoclax; the CD33 antibody drug conjugate gemtuzumab ozogamicin; three FLT3 inhibitors (midostaurin, gilteritinib, quizartinib); three IDH inhibitors (ivosidenib and olutasidenib targeting IDH1 mutations; enasidenib targeting IDH2 mutations); two oral hypomethylating agents (oral poorly absorbable azacitidine; fully absorbable decitabine-cedazuridine [latter approved as an alternative to parenteral hypomethylating agents in myelodysplastic syndrome and chronic myelomonocytic leukemia but commonly used in AML]); and CPX-351 (encapsulated liposomal 5:1 molar ratio of cytarabine and daunorubicin), and glasdegib (hedgehog inhibitor). Other targeted therapies (menin inhibitors, CD123 antibody-drug conjugates) are showing promising results. To achieve optimal results in such a rare and heterogeneous entity as AML requires expertise, familiarity with this rare cancer, and the access to, and delivery of disparate therapies under rigorous supportive care conditions. In this review, we update the standard-of-care and investigational therapies and outline promising current and future research directions.

DOI: https://doi.org/10.1038/s41408-024-01143-2
Ther Adv Hematol. 2024 ;15 20406207241275376

Phase I/II study of the clinical activity and safety of GSK3326595 in patients with myeloid neoplasms.

Justin Watts, Mark D Minden, Kimo Bachiashvili, Andrew M Brunner, Sameem Abedin, Timothy Crossman, Magdalena Zajac, Veronica Moroz, Jacqueline L Egger, Aarti Tarkar, Brandon E Kremer, Olena Barbash, Gautam Borthakur.

  Background: GSK3326595 is a potent, selective, reversible protein arginine methyltransferase 5 (PRMT5) inhibitor under investigation for treatment of myelodysplastic syndrome (MDS), chronic myelomonocytic leukemia (CMML), and acute myeloid leukemia (AML). In preclinical models of AML, PRMT5 inhibition decreased proliferation and increased cell death, supporting additional clinical research in myeloid neoplasms.Objectives: To determine the clinical activity, safety, tolerability, dosing, additional measures of clinical activity, pharmacokinetics, and pharmacodynamics of GSK3326595.
Design: In part 1 of this open-label, multicenter, multipart, phase I/II study, adults with relapsed/refractory myeloid neoplasms (e.g., MDS, CMML, and AML) received monotherapy with 400 or 300 mg oral GSK3326595 once daily. Study termination occurred prior to part 2 enrollment.
Methods: Clinical activity was determined by the clinical benefit rate (CBR; proportion of patients achieving complete remission (CR), complete marrow remission (mCR), partial remission, stable disease (SD) >8 weeks, or hematologic improvement). Adverse events (AEs) were assessed by incidence and severity. Exploratory examination of spliceosome mutations was performed to determine the relationship between genomic profiles and clinical response to GSK3326595.
Results: Thirty patients with a median age of 73.5 years (range, 47-90) were enrolled; 13 (43%) and 17 (57%) received 400 and 300 mg of GSK3326595, respectively. Five (17%) patients met CBR criteria: 4 (13%) with SD >8 weeks and 1 (3%) achieving mCR. Of five patients with clinical benefit: three had SRSF2 mutation, one U2AF1, and one was splicing factor wild-type. Frequent GSK3326595-related AEs were decreased platelet count (27%), dysgeusia (23%), fatigue (20%), and nausea (20%). GSK3326595 had rapid absorption, with a T max of approximately 2 h and a terminal half-life of 4-6 h.
Conclusion: GSK3326595 monotherapy had limited clinical activity in heavily pretreated patients despite robust target engagement. The safety profile was broadly consistent with other published PRMT5 inhibitor studies.
Trial registration: ClinicalTrials.gov: NCT03614728.

Keywords:  GSK3326595; PRMT5; acute myeloid leukemia; chronic myelomonocytic leukemia; myelodysplastic syndrome; myeloid neoplasm

DOI:  https://doi.org/10.1177/20406207241275376
Nat Genet. 2024 Sep 18.

Pharmacological restriction of genomic binding sites redirects PU.1 pioneer transcription factor activity.

Samuel J Taylor, Jacob Stauber, Oliver Bohorquez, Goichi Tatsumi, Rajni Kumari, Joyeeta Chakraborty, Boris A Bartholdy, Emily Schwenger, Sriram Sundaravel, Abdelbasset A Farahat, Justin C Wheat, Mendel Goldfinger, Amit Verma, Arvind Kumar, David W Boykin, Kristy R Stengel, Gregory M K Poon, Ulrich Steidl.

Transcription factor (TF) DNA-binding dynamics govern cell fate and identity. However, our ability to pharmacologically control TF localization is limited. Here we leverage chemically driven binding site restriction leading to robust and DNA-sequence-specific redistribution of PU.1, a pioneer TF pertinent to many hematopoietic malignancies. Through an innovative technique, 'CLICK-on-CUT&Tag', we characterize the hierarchy of de novo PU.1 motifs, predicting occupancy in the PU.1 cistrome under binding site restriction. Temporal and single-molecule studies of binding site restriction uncover the pioneering dynamics of native PU.1 and identify the paradoxical activation of an alternate target gene set driven by PU.1 localization to second-tier binding sites. These transcriptional changes were corroborated by genetic blockade and site-specific reporter assays. Binding site restriction and subsequent PU.1 network rewiring causes primary human leukemia cells to differentiate. In summary, pharmacologically induced TF redistribution can be harnessed to govern TF localization, actuate alternate gene networks and direct cell fate.

DOI: https://doi.org/10.1038/s41588-024-01911-7
J Biol Chem. 2024 Sep 12. pii: S0021-9258(24)02278-6. [Epub ahead of print] 107777

Drug-resistant menin variants retain high binding affinity and interactions with MLL1.

Joshua Ray, Bradley Clegg, Jolanta Grembecka, Tomasz Cierpicki.

  Menin is an essential oncogenic co-factor of MLL1 fusion proteins in acute leukemias and inhibitors of the menin-MLL1 interaction are under evaluation in clinical trials. Recent studies found emerging resistance to menin inhibitor treatment in leukemia patients as a result of somatic mutations in menin. To understand how patient mutations in menin affect the interaction with MLL1, we performed systematic characterization of the binding affinity of these menin mutants (T349M, M327I, G331R and G331D) and the N-terminal fragment of MLL1. We also determined the crystal structures of menin patient mutants and their complexes with MLL1-derived peptides. We found that drug-resistant mutations in menin occur at a site adjacent to the MLL1 binding site, but they do not affect MLL1 binding to menin. On the contrary, our structural analysis shows that all these point mutations in menin generate steric clash with menin inhibitors. We also found that mutation G331D results in a very slow dissociation of MLL1 from menin and this mutant might be particularly difficult to inhibit with small molecule drugs. This work provides structural information to support the development of a new generation of small molecule inhibitors that overcome resistance caused by menin mutations.

Keywords:  Drug resistance; Leukemia; Ligand-binding protein; Mutant; Protein structure; Protein-protein interaction

DOI:  https://doi.org/10.1016/j.jbc.2024.107777
Blood Cancer J. 2024 Sep 16. 14(1): 160

Therapy-related AML: long-term outcome in a large cohort of AML-patients with intensive and non-intensive therapy.

Sophia Gross, Jana Ihlow, Leonie Busack, Kacper Adamiak, Jens Schrezenmeier, Julia Jesse, Michaela Schwarz, Anne Flörcken, Lam Giang Vuong, Kathrin Rieger, Jan Krönke, Philipp le Coutre, Vivien Boldt, Ann-Christin von Brünneck, David Horst, Thomas Burmeister, Igor-Wolfgang Blau, Ulrich Keller, Lars Bullinger, Jörg Westermann.

Therapy-related acute myeloid leukemia (t-AML) often exhibits adverse (genetic) features. There is ongoing discussion on the impact of t-AML on long-term outcome in AML. Therefore, we retrospectively analyzed clinical and biological characteristics of 1133 AML patients (225 t-AML patients and 908 de novo AML patients) with a median follow-up of 81.8 months. T-AML patients showed more adverse genetic alterations, higher age and more comorbidities as compared to de novo AML. Median OS in intensively treated t-AML patients was 13.7 months as compared to 39.4 months in de novo AML (p < 0.001). With non-intensive therapy, OS did not differ significantly (p = 0.394). With intensive therapy, significant differences in favor of de novo AML were observed in the ELN intermediate I/II (p = 0.009) and adverse (p = 0.016) risk groups but not within favorable risk groups (APL p = 0.927, ELN favorable p = 0.714). However, t-AML was no independent risk factor for OS (p = 0.103), RR (p = 0.982) and NRM (p = 0.320) in the multivariate analysis. A limitation of our study is an ELN 2010 risk stratification due to a lack of more comprehensive molecular data according to ELN 2022. We conclude that therapeutic algorithms in t-AML, in particular with regard to allo-HSCT, should be guided by ELN genetic risk rather than classification as t-AML alone. Our data support the WHO and ICC 2022 classifications, which include t-AML as diagnostic qualifier rather than a separate subcategory.

DOI: https://doi.org/10.1038/s41408-024-01140-5
Br J Haematol. 2024 Sep 14.

Leucocytosis during induction therapy with all-trans-retinoic acid and arsenic trioxide in acute promyelocytic leukaemia predicts differentiation syndrome and treatment-related complications.

Laura Cicconi, Marialaura Bisegna, Carmelo Gurnari, David Fanciullo, Alfonso Piciocchi, Giovanni Marsili, Clara Minotti, Emilia Scalzulli, Bianca Mandelli, Luca Guarnera, Salvatore Perrone, Elettra Ortu La Barbera, Sergio Mecarocci, Annalisa Biagi, Natalia Cenfra, Andrea Corbingi, Maria Cristina Scerpa, Adriano Venditti, Maurizio Martelli, Maria Teresa Voso, Massimo Breccia, Alessandro Pulsoni.

  All-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) represent the standard of care for low-intermediate risk acute promyelocytic leukaemia (APL). Leucocytosis during induction with ATRA-ATO represents a common complication with an incidence of up to 60%. To identify predictive factors for this complication, we studied a cohort of 65 low-intermediate risk APL patients treated with ATRA-ATO in three highly specialized Italian centres. Overall, 39/65 (60%) patients developed leucocytosis, with a peak in leucocyte count being most frequent in the second week from diagnosis. All cases were successfully managed with hydroxyurea. Predictive factors for leucocytosis in univariate analysis were lower platelet counts (odds ratio [OR] 0.98, 0.97-1.00, p = 0.018), lower fibrinogen levels (OR 0.36, 0.17-0.66, p = 0.003), higher bone marrow blast infiltration (OR 1.03, 1.01-1.07, p = 0.021) and CD117 expression by flow (OR 1.04, 1.01-1.08, p = 0.012). Multivariate analysis confirmed lower levels of fibrinogen at diagnosis as the strongest predictive factor for the development of leucocytosis (OR 0.36, 0.15-0.72, p = 0.009). Differentiation syndrome (DS) occurred only in patients developing leucocytosis showing a strict correlation with rising leucocytes counts (16/39 vs. 0/26, p < 0.001). In addition, other treatment-related complications including QTc prolongation, cardiac events, liver, and haematological toxicities were significantly more frequent in patients experiencing leucocytosis (22/39 vs. 3/26, p < 0.001). In conclusion, APL patients undergoing ATRA-ATO therapy with lower fibrinogen levels and platelet counts at diagnosis and with a massive bone marrow blast infiltrate should be carefully monitored for the development of leucocytosis during induction. DS and other treatment-related complications seem to occur almost exclusively in patients developing leucocytosis, who should necessarily receive DS prophylaxis and more intensive monitoring and supportive therapy to prevent treatment complications.

Keywords:  ATO; ATRA; acute promyelocytic leukaemia; leucocytosis

DOI:  https://doi.org/10.1111/bjh.19759
Blood Adv. 2024 Sep 18. pii: bloodadvances.2024013777. [Epub ahead of print]

Risk of Bleeding in Essential Thrombocythemia Patients with Extreme Thrombocytosis.

Rathnam K Venkat, Robert A Redd, Amyah C Harris, Martin J Aryee, Anna E Marneth, Baransel Kamaz, Chulwoo J Kim, Mohammed Wazir, Lachelle D Weeks, Maximilian Stahl, Daniel J DeAngelo, R Coleman Lindsley, Marlise R Luskin, Gabriela S Hobbs, Joan How.

About 25% of essential thrombocythemia (ET) patients present with extreme thrombocytosis (ExT), defined as having a platelet count ≥1000 x 10^9/L. ExT patients may have an increased bleeding risk associated with acquired von Willebrand syndrome. We retrospectively analyzed the risk of bleeding and thrombosis in ExT vs. non-ExT ET patients at Dana Farber Cancer Institute and Massachusetts General Hospital from 2014-2022 to inform treatment decisions. We abstracted the first major bleed, clinically relevant non-major bleed (CRNMB), and thrombotic event from medical records. We identified 128 (28%) ExT patients and 323 (72%) non-ExT patients. Cumulative incidence of bleeding was not different in ExT vs. non-ExT patients (21% vs. 13%, p=0.28 for major bleed; 16% vs. 15%, p=0.50 for CRNMB). Very low and low thrombotic risk ExT patients were more likely to be cytoreduced compared to very low and low risk non-ExT patients (69% vs. 50%, p=0.060 for very low risk; 83% vs. 53%, p=0.0059 for low risk). However, we found no differences in bleeding between ExT and non-ExT patients when restricting the risk of bleed from diagnosis to cytoreduction start date (28% vs. 19%, p=0.29 for major bleed; 24% vs. 22%, p=0.75 for CRNMB). Cumulative incidence of thrombosis was also not different between ExT and non-ExT patients (28% vs. 25%, p=0.98). This suggests that cytoreduction may not be necessary to reduce bleeding risk based only on a platelet count of 1 million. We identified novel risk factors for bleeding in ET patients including diabetes mellitus and the DNMT3A mutation.

DOI: https://doi.org/10.1182/bloodadvances.2024013777
Sci Adv. 2024 Sep 20. 10(38): eadq1476

CCR2 cooperativity promotes hematopoietic stem cell homing to the bone marrow.

Stephanie N Hurwitz, Danielle R Kobulsky, Seul K Jung, Jennifer J Chia, Jason M Butler, Peter Kurre.

Cross-talk between hematopoietic stem and progenitor cells (HSPCs) and bone marrow (BM) cells is critical for homing and sustained engraftment after transplantation. In particular, molecular and physical adaptation of sinusoidal endothelial cells (ECs) promote HSPC BM occupancy; however, signals that govern these events are not well understood. Extracellular vesicles (EVs) are mediators of cell-cell communication crucial in shaping tissue microenvironments. Here, we demonstrate that integrin α4β7 on murine HSPC EVs targets uptake into ECs. In BM ECs, HSPC EVs induce up-regulation of C-C motif chemokine receptor 2 (CCR2) ligands that synergize with CXCL12-CXCR4 signaling to promote BM homing. In nonirradiated murine models, marrow preconditioning with HSPC EVs or recombinant CCR2 ligands improves homing and early graft occupancy after transplantation. These findings identify a role for HSPC EVs in remodeling ECs, newly define CCR2-dependent graft homing, and inform novel translational conditioning strategies to improve HSPC transplantation.

DOI: https://doi.org/10.1126/sciadv.adq1476