bims-tremyl 2024-03-17 papers

bims-tremyl

Biomed News

on Therapy resistance biology in myeloid leukemia

Issue of 2024‒03‒17
28 papers selected by
Paolo Gallipoli, Barts Cancer Institute, Queen Mary University of London

Gilteritinib as Post-Transplant Maintenance for Acute Myeloid Leukemia With Internal Tandem Duplication Mutation of FLT3.
Mutation order in acute myeloid leukemia identifies uncommon patterns of evolution and illuminates phenotypic heterogeneity.
Allogeneic haematopoietic cell transplantation for advanced systemic mastocytosis: Best practice recommendations on behalf of the EBMT Practice Harmonisation and Guidelines Committee.
p53 biology and reactivation for improved therapy in MDS and AML.
Autophagy inhibition-induced cytosolic DNA sensing combined with differentiation therapy induces irreversible myeloid differentiation in leukemia cells.
Identification of Nonfunctional Alternatively Spliced Isoforms of STING in Human Acute Myeloid Leukemia.
A phase I trial of pevonedistat in combination with ruxolitinib for the treatment of myelofibrosis.
European Stop Tyrosine Kinase Inhibitor Trial (EURO-SKI) in Chronic Myeloid Leukemia: Final Analysis and Novel Prognostic Factors for Treatment-Free Remission.
ArCH: Improving the performance of clonal hematopoiesis variant calling and interpretation.
Addition of single dose gemtuzumab ozogamicin to intensive induction chemotherapy in core-binding factor acute myeloid leukemia.
STAT3 protects hematopoietic stem cells by preventing activation of a deleterious autocrine type-I interferon response.
Hu8F4-CAR T cells with mutated Fc spacer segment improve target-specificity and mediate anti-leukemia activity in vivo.
Acquired immune resistance is associated with interferon signature and modulation of KLF6/c-MYB transcription factors in myeloid leukemia.
cMPL-Based Purification and Depletion of Human Hematopoietic Stem Cells: Implications for Pre-Transplant Conditioning.
Efficacy and safety of mitoxantrone, etoposide, and cytarabine for treatment of relapsed or refractory acute myeloid leukemia.
IDALLO study: A retrospective multicenter study of the SFGM-TC evaluating the efficacy and safety of ivosidenib in relapsed IDH1-mutated AML after allogeneic hematopoietic cell transplantation.
Treatment of refractory/relapsed Diamond-Blackfan anaemia with eltrombopag.
Active site remodeling in tumor-relevant IDH1 mutants drives distinct kinetic features and potential resistance mechanisms.
JAK inhibitor treatment-resistant splenomegaly before transplantation in myelofibrosis: Splenectomy or radiotherapy?
Investigation of Serum Albumin as a Dynamic Treatment-Specific Surrogate for Outcomes in Patients With Myelofibrosis Treated With Ruxolitinib.
Long-term survival and functional outcomes of critically ill patients with hematologic malignancies: a Canadian multicenter prospective study.
Mitochondrial complex I activity in microglia sustains neuroinflammation.
Impact of clonal hematopoiesis of indeterminate potential on hepatocellular carcinoma in individuals with steatotic liver disease.
Capture-based targeted sequencing using a T-cell control in myeloid malignancies and idiopathic cytopenias.
Combined Effect of Unrelated Donor Age and HLA Peptide-Binding Motifs (PBM) Match Status on HCT Outcomes.
Efficacy and safety of bosutinib in patients treated with prior imatinib and/or dasatinib and/or nilotinib: Subgroup analyses from the phase 4 BYOND study.
Metabolic reprogramming of cancer cells by JMJD6-mediated pre-mRNA splicing associated with therapeutic response to splicing inhibitor.
Continuous evolution of compact protein degradation tags regulated by selective molecular glues.

J Clin Oncol. 2024 Mar 12. JCO2302474

Gilteritinib as Post-Transplant Maintenance for Acute Myeloid Leukemia With Internal Tandem Duplication Mutation of FLT3.

BMT-CTN 1506/MORPHO Study Investigators

PURPOSE: Allogeneic hematopoietic cell transplantation (HCT) improves outcomes for patients with acute myeloid leukemia (AML) harboring an internal tandem duplication mutation of FLT3 (FLT3-ITD) AML. These patients are routinely treated with a FLT3 inhibitor after HCT, but there is limited evidence to support this. Accordingly, we conducted a randomized trial of post-HCT maintenance with the FLT3 inhibitor gilteritinib (ClinicalTrials.gov identifier: NCT02997202) to determine if all such patients benefit or if detection of measurable residual disease (MRD) could identify those who might benefit.METHODS: Adults with FLT3-ITD AML in first remission underwent HCT and were randomly assigned to placebo or 120 mg once daily gilteritinib for 24 months after HCT. The primary end point was relapse-free survival (RFS). Secondary end points included overall survival (OS) and the effect of MRD pre- and post-HCT on RFS and OS.
RESULTS: Three hundred fifty-six participants were randomly assigned post-HCT to receive gilteritinib or placebo. Although RFS was higher in the gilteritinib arm, the difference was not statistically significant (hazard ratio [HR], 0.679 [95% CI, 0.459 to 1.005]; two-sided P = .0518). However, 50.5% of participants had MRD detectable pre- or post-HCT, and, in a prespecified subgroup analysis, gilteritinib was beneficial in this population (HR, 0.515 [95% CI, 0.316 to 0.838]; P = .0065). Those without detectable MRD showed no benefit (HR, 1.213 [95% CI, 0.616 to 2.387]; P = .575).
CONCLUSION: Although the overall improvement in RFS was not statistically significant, RFS was higher for participants with detectable FLT3-ITD MRD pre- or post-HCT who received gilteritinib treatment. To our knowledge, these data are among the first to support the effectiveness of MRD-based post-HCT therapy.

DOI: https://doi.org/10.1200/JCO.23.02474
Leukemia. 2024 Mar 11.

Mutation order in acute myeloid leukemia identifies uncommon patterns of evolution and illuminates phenotypic heterogeneity.

Matthew Schwede, Katharina Jahn, Jack Kuipers, Linde A Miles, Robert L Bowman, Troy Robinson, Ken Furudate, Hidetaka Uryu, Tomoyuki Tanaka, Yuya Sasaki, Asiri Ediriwickrema, Brooks Benard, Andrew J Gentles, Ross Levine, Niko Beerenwinkel, Koichi Takahashi, Ravindra Majeti.

Acute myeloid leukemia (AML) has a poor prognosis and a heterogeneous mutation landscape. Although common mutations are well-studied, little research has characterized how the sequence of mutations relates to clinical features. Using published, single-cell DNA sequencing data from three institutions, we compared clonal evolution patterns in AML to patient characteristics, disease phenotype, and outcomes. Mutation trees, which represent the order of select mutations, were created for 207 patients from targeted panel sequencing data using 1 639 162 cells, 823 mutations, and 275 samples. In 224 distinct orderings of mutated genes, mutations related to DNA methylation typically preceded those related to cell signaling, but signaling-first cases did occur, and had higher peripheral cell counts, increased signaling mutation homozygosity, and younger patient age. Serial sample analysis suggested that NPM1 and DNA methylation mutations provide an advantage to signaling mutations in AML. Interestingly, WT1 mutation evolution shared features with signaling mutations, such as WT1-early being proliferative and occurring in younger individuals, trends that remained in multivariable regression. Some mutation orderings had a worse prognosis, but this was mediated by unfavorable mutations, not mutation order. These findings add a dimension to the mutation landscape of AML, identifying uncommon patterns of leukemogenesis and shedding light on heterogeneous phenotypes.

DOI: https://doi.org/10.1038/s41375-024-02211-z
Leukemia. 2024 Mar 12.

Allogeneic haematopoietic cell transplantation for advanced systemic mastocytosis: Best practice recommendations on behalf of the EBMT Practice Harmonisation and Guidelines Committee.

Donal P McLornan, Tomasz Czerw, Gandhi Damaj, Mark Ethell, Carmelo Gurnari, Juan Carlos Hernández-Boluda, Nicola Polverelli, Juliana Schwaab, Katja Sockel, Greco Raffaella, Francesco Onida, Isabel Sánchez-Ortega, Giorgia Battipaglia, Chiara Elena, Jason Gotlib, Andreas Reiter, Julien Rossignol, Celalettin Ustun, Peter Valent, Ibrahim Yakoub-Agha, Deepti H Radia.

Systemic Mastocytosis (SM) is a multifaceted clinically heterogeneous disease. Advanced SM (AdvSM) comprises three entities: aggressive SM (ASM), mast cell leukaemia (MCL) and SM with an associated hematologic neoplasm (SM-AHN), the latter accounting for 60-70% of all AdvSM cases. Detection of a disease-triggering mutation in the KIT gene (esp. KIT D816V) in >90% of the patients with ASM or SM-AHN has led to a significant improvement in therapeutic options by the implementation of two KIT-targeting kinase inhibitors: midostaurin and avapritinib. Although complete remissions have been reported, neither of these targeted agents is 'curative' in all patients and the duration of responses varies. The median overall survival, depending on the WHO subtype and scoring result, is approximately 1 to 4 years. Although the European Competence Network on Mastocytosis (ECNM) and American Initiative in Mast Cell Diseases (AIM) consensus groups recommend allogeneic haematopoietic cell transplantation (allo-HCT) in drug-resistant and other high-risk patients, there is a relative lack of information to guide clinicians on which patients with AdvSM should be considered for transplant, and how KIT inhibitors may fit into the transplant algorithm, including their use pre- and post-transplant to optimise outcomes. Following the generation of an expert panel with a specialist interest in allo-HCT and mastocytosis, these best practice recommendations were generated according to the European Society for Blood and Marrow Transplantation (EBMT) Practice Harmonisation and guidelines and ECNM methodology. We aim to provide a practical, clinically relevant and up-to-date framework to guide allo-HCT in AdvsM in 2024 and beyond.

DOI: https://doi.org/10.1038/s41375-024-02182-1
Biomark Res. 2024 Mar 13. 12(1): 34

p53 biology and reactivation for improved therapy in MDS and AML.

Joanna E Zawacka.

  Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) originate from preleukemic hematopoietic conditions, such as clonal hematopoiesis of indeterminate potential (CHIP) or clonal cytopenia of undetermined significance (CCUS) and have variable outcomes despite the successful implementation of targeted therapies. The prognosis differs depending on the molecular subgroup. In patients with TP53 mutations, the most inferior outcomes across independent studies were observed. Myeloid malignancies with TP53 mutations have complex cytogenetics and extensive structural variants. These factors contribute to worse responses to induction therapy, demethylating agents, or venetoclax-based treatments. Survival of patients with biallelic TP53 gene mutations is often less than one year but this depends on the type of treatment applied. It is still controversial whether the allelic state of mutant TP53 impacts the outcomes in patients with AML and high-risk MDS. Further studies are needed to justify estimating TP53 LOH status for better risk assessment. Yet, TP53-mutated MDS, MDS/AML and AML are now classified separately in the International Consensus Classification (ICC). In the clinical setting, the wild-type p53 protein is reactivated pharmacologically by targeting p53/MDM2/MDM4 interactions and mutant p53 reactivation is achieved by refolding the DNA binding domain to wild-type-like conformation or via targeted degradation of the mutated protein. This review discusses our current understanding of p53 biology in MDS and AML and the promises and failures of wild-type and mutant p53 reactivation in the clinical trial setting.

Keywords:  AML; Improved therapy; MDM2; MDM4; MDS; p53; p73

DOI:  https://doi.org/10.1186/s40364-024-00579-9
Cancer Res Commun. 2024 Mar 11.

Autophagy inhibition-induced cytosolic DNA sensing combined with differentiation therapy induces irreversible myeloid differentiation in leukemia cells.

Tomohisa Baba, Utano Tomaru, Atsushi Hirao, Naofumi Mukaida, Yoshikazu Johmura.

Accumulating evidence indicates that various oncogenic mutations interfere with normal myeloid differentiation of leukemogenic cells during the early process of acute myeloid leukemia (AML) development. Differentiation therapy is a therapeutic strategy capable of terminating leukemic expansion by reactivating the differentiation potential; however, the plasticity and instability of leukemia cells counteract the establishment of treatments aimed at irreversibly inducing and maintaining their differentiation states. Based on our previous observation that autophagy inhibitor treatment induces the accumulation of cytosolic DNA and activation of cytosolic DNA-sensor signaling selectively in leukemia cells, we herein examined the synergistic effect of cytosolic DNA-sensor signaling activation with conventional differentiation therapy on AML. The combined treatment succeeded in inducing irreversible differentiation in AML cell lines. Mechanistically, cytosolic DNA was sensed by absent in melanoma 2 (AIM2), a cytosolic DNA sensor. Activation of the AIM2 inflammasome resulted in the accumulation of p21 through the inhibition of its proteasomal degradation, thereby facilitating the myeloid differentiation. Importantly, the combined therapy dramatically reduced the total leukemia cell counts and proportion of blast cells in the spleens of AML mice. Collectively, these findings indicate that the autophagy inhibition-cytosolic DNA-sensor signaling axis can potentiate AML differentiation therapy.

DOI: https://doi.org/10.1158/2767-9764.CRC-23-0507
Cancer Res Commun. 2024 Mar 13.

Identification of Nonfunctional Alternatively Spliced Isoforms of STING in Human Acute Myeloid Leukemia.

Akash R Boda, Arthur J Liu, Susana Castro-Pando, Benjamin T Whitfield, Jeffrey J Molldrem, Gheath Al-Atrash, Maria Emilia Di Francesco, Philip Jones, Casey R Ager, Michael A Curran.

Lack of robust activation of Stimulator of Interferon Genes (STING) pathway and subsequent induction of type I interferon (IFN) responses is considered a barrier to antitumor immunity in acute myeloid leukemia (AML). Using common human AML cell lines as in vitro tools to evaluate the efficacy of novel STING agonists, we found most AML lines to be poor producers of IFNs upon exposure to extremely potent agonists, suggesting cell-intrinsic suppression of STING signaling may occur. We observed unexpected patterns of response that did not correlate with levels of STING pathway components or of known enzymes associated with resistance. To identify a genetic basis for these observations, we cloned and sequenced STING from the cDNA of human AML cell lines and found both frequent mutations and deviations from normal RNA splicing. We identified two novel spliced isoforms of STING in these lines and validated their expression in primary human AML samples. When transduced into reporter cells, these novel STING isoforms exhibited complete insensitivity to agonist stimulation. These observations identify alternative splicing as a mechanism of STING pathway suppression and suggest that most AML silences the STING pathway through direct modification rather than through engagement of external inhibitory factors.

DOI: https://doi.org/10.1158/2767-9764.CRC-24-0095
Ther Adv Hematol. 2024 ;15 20406207241237607

A phase I trial of pevonedistat in combination with ruxolitinib for the treatment of myelofibrosis.

Tim Kong, Nicole Gaudin, Karyn Gordon, Maggie J Cox, Amy W Zhou, Stephen T Oh.

  Janus kinase 2 (JAK2) inhibitors such as ruxolitinib have become standard-of-care therapy for patients with myeloproliferative neoplasms (MPNs); however, activation of alternate oncogenic pathways including nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) has limited durable response as single-agent therapy. With the rationale of targeting both pathways, we conducted a phase I dose escalation trial of pevonedistat in combination with ruxolitinib for the treatment of patients with myelofibrosis (NCT03386214). The primary objective was to assess the safety and tolerability of combination therapy with additional objectives of treatment efficacy and alterations of biomarkers. There were no dose-limiting toxicities observed with most adverse events being limited to grades 1/2. In secondary measures, anemia response was observed in two patients. Pro-inflammatory cytokines and iron parameters were longitudinally assessed, which revealed suppression of interleukin-6 and interferon-gamma in a dose-dependent manner across a subset of patients. These results suggest that combination therapy targeting both JAK2 and NFκB may hold clinical merit for MPN patients.

Keywords:  JAK2; MLN4924; NFκB; clinical trial; myeloproliferative neoplasms; pevonedistat; ruxolitinib

DOI:  https://doi.org/10.1177/20406207241237607
J Clin Oncol. 2024 Mar 12. JCO2301647

European Stop Tyrosine Kinase Inhibitor Trial (EURO-SKI) in Chronic Myeloid Leukemia: Final Analysis and Novel Prognostic Factors for Treatment-Free Remission.

EURO-SKI Investigators

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.The European Stop Kinase Inhibitors (EURO-SKI) study is the largest clinical trial for investigating the cessation of tyrosine kinase inhibitors (TKIs) in patients with chronic myeloid leukemia in stable deep molecular remission (DMR). Among 728 patients, 434 patients (61%; 95% CI, 57 to 64) remained in major molecular response (MMR) at 6 months and 309 patients of 678 (46%; 95% CI, 42 to 49) at 36 months. Duration of TKI treatment and DMR before TKI stop were confirmed as significant factors for the prediction of MMR loss at 6 months. In addition, the type of BCR::ABL1 transcript was identified as a prognostic factor. For late MMR losses after 6 months, TKI treatment duration, percentage of blasts in peripheral blood, and platelet count at diagnosis were significant factors in multivariate analysis. For the entire study period of 36 months, multiple logistic regression models confirmed duration of treatment, blasts, and transcript type as independent factors for MMR maintenance. In addition to the duration of treatment, transcript type as well as blasts in peripheral blood at diagnosis should be considered as important factors to predict treatment-free remission.

DOI: https://doi.org/10.1200/JCO.23.01647
Bioinformatics. 2024 Mar 14. pii: btae121. [Epub ahead of print]

ArCH: Improving the performance of clonal hematopoiesis variant calling and interpretation.

Irenaeus C C Chan, Alex Panchot, Evelyn Schmidt, Samantha McNulty, Brian J Wiley, Jie Liu, Kimberly Turner, Lea Moukarzel, Wendy S W Wong, Duc Tran, J Scott Beeler, Armel Landry Batchi-Bouyou, Mitchell J Machiela, Danielle M Karyadi, Benjamin J Krajacich, Junhua Zhao, Semyon Kruglyak, Bryan Lajoie, Shawn Levy, Minal Patel, Philip W Kantoff, Christopher E Mason, Daniel C Link, Todd E Druley, Konrad H Stopsack, Kelly L Bolton.

MOTIVATION: The acquisition of somatic mutations in hematopoietic stem and progenitor stem cells (HSPCs) with resultant clonal expansion, termed clonal hematopoiesis (CH), is associated with increased risk of hematologic malignancies and other adverse outcomes. CH is generally present at low allelic fractions, but clonal expansion and acquisition of additional mutations leads to hematologic cancers in a small proportion of individuals. With high depth and high sensitivity sequencing, CH can be detected in most adults and its clonal trajectory mapped over time. However, accurate CH variant calling is challenging due to the difficulty in distinguishing low frequency CH mutations from sequencing artifacts. The lack of well-validated bioinformatic pipelines for CH calling may contribute to lack of reproducibility in studies of CH.RESULTS: ArCH, an Artifact filtering Clonal Hematopoiesis variant calling pipeline for detecting single nucleotide variants (SNVs) and short insertions/deletions (INDELs) by combining the output of four variant calling tools and filtering based on variant characteristics and sequencing error rate estimation. ArCH is an end-to-end cloud-based pipeline optimized to accept a variety of inputs with customizable parameters adaptable to multiple sequencing technologies, research questions, and datasets. Using deep targeted sequencing data generated from six AML patient tumor: normal dilutions, 31 blood samples with orthogonal validation, and 21 blood samples with technical replicates, we show that ArCH improves the sensitivity and positive predictive value of CH variant detection at low allele frequencies compared to standard application of commonly used variant calling approaches.
AVAILABILITY: The code for this workflow is available at: https://github.com/kbolton-lab/ArCH.
SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

DOI: https://doi.org/10.1093/bioinformatics/btae121
Leuk Res. 2024 Feb 28. pii: S0145-2126(24)00033-X. [Epub ahead of print]139 107467

Addition of single dose gemtuzumab ozogamicin to intensive induction chemotherapy in core-binding factor acute myeloid leukemia.

Garrett Bourne, Kendall Diebold, Manuel Espinoza-Gutarra, Zaid Al-Kadhimi, Kimo Bachiashvili, Sravanti Rangaraju, Pankit Vachhani, Ravi Bhatia, Omer Jamy.

  In a meta-analysis of 5 trials, the addition of gemtuzumab ozogamicin (GO) to intensive induction chemotherapy led to a survival benefit in patients with core-binding factor (CBF) acute myeloid leukemia (AML). Given the heterogeneous incorporation of GO in clinical trials, the ideal dose and schedule remains unclear. We conducted a single-center retrospective analysis to compare outcomes of patients with CBF-AML treated with intensive induction chemotherapy, with or without a single dose of GO 3 mg/m2, during induction only. We included 87 patients (GO=32, control=55). The composite complete remission (cCR) rate was higher in the control group (93%) compared to the GO group (82%) (p<0.001). The rate of measurable residual disease (MRD) negative cCR, by flow cytometry, was similar between both groups. There were no significant differences between the two groups in terms of toxicity. The 3-year relapse-free survival (RFS) for both groups was similar (71% vs 68%, p=0.5). The 3-year overall survival (OS) for the GO group was 68%, compared to 66% for the control group (p=0.9).In multivariable analysis, age and MRD positive status were risk factors for inferior outcomes. We find that survival of patients with CBF-AML is favorable in the real-world setting. The addition of single-dose GO, during induction, did not lead to a higher remission rate or survival benefit, when compared to intensive chemotherapy without GO. Further investigation into the incorporation of GO in the treatment algorithm for CBF-AML is needed.

Keywords:  Acute Myeloid Leukemia; Core-Binding Factor; Gemtuzumab Ozogamicin; Intensive Chemotherapy

DOI:  https://doi.org/10.1016/j.leukres.2024.107467
Leukemia. 2024 Mar 11.

STAT3 protects hematopoietic stem cells by preventing activation of a deleterious autocrine type-I interferon response.

Bhakti Patel, Yifan Zhou, Rachel L Babcock, Feiyang Ma, M Anna Zal, Dhiraj Kumar, Yusra B Medik, Laura M Kahn, Josué E Pineda, Elizabeth M Park, Sarah M Schneider, Ximing Tang, Maria Gabriela Raso, Collene R Jeter, Tomasz Zal, Karen Clise-Dwyer, Khandan Keyomarsi, Filippo G Giancotti, Simona Colla, Stephanie S Watowich.

Hematopoietic stem and progenitor cells (HSPCs) maintain blood-forming and immune activity, yet intrinsic regulators of HSPCs remain elusive. STAT3 function in HSPCs has been difficult to dissect as Stat3-deficiency in the hematopoietic compartment induces systemic inflammation, which can impact HSPC activity. Here, we developed mixed bone marrow (BM) chimeric mice with inducible Stat3 deletion in 20% of the hematopoietic compartment to avoid systemic inflammation. Stat3-deficient HSPCs were significantly impaired in reconstitution ability following primary or secondary bone marrow transplantation, indicating hematopoietic stem cell (HSC) defects. Single-cell RNA sequencing of Lin-ckit+Sca1+ BM cells (LSKs) revealed aberrant activation of cell cycle, p53, and interferon (IFN) pathways in Stat3-deficient HSPCs. Stat3-deficient LSKs accumulated γH2AX and showed increased expression of DNA sensors and type-I IFN (IFN-I), while treatment with A151-ODN inhibited expression of IFN-I and IFN-responsive genes. Further, the blockade of IFN-I receptor signaling suppressed aberrant cell cycling, STAT1 activation, and nuclear p53 accumulation. Collectively, our results show that STAT3 inhibits a deleterious autocrine IFN response in HSCs to maintain long-term HSC function. These data signify the importance of ensuring therapeutic STAT3 inhibitors are targeted specifically to diseased cells to avoid off-target loss of healthy HSPCs.

DOI: https://doi.org/10.1038/s41375-024-02218-6
Res Sq. 2024 Feb 19. pii: rs.3.rs-3937972. [Epub ahead of print]

Hu8F4-CAR T cells with mutated Fc spacer segment improve target-specificity and mediate anti-leukemia activity in vivo.

Jeffrey Molldrem, Hong He, Rolando Vedia, Sijie Lu, Qiaochuan Li, Kathryn Cox, Lisa St John, Anna Sergeeva, Karen Clise-Dwyer, Gheath Alatrash, Elizabeth Shpall, Qing Ma.

Hu8F4 is a T cell receptor (TCR)-like antibody with high affinity for leukemia-associated antigen PR1/HLA-A2 epitope. Adapted into a chimeric antigen receptor (CAR) format, Hu8F4-CAR is comprised of the Hu8F4 scFv, the human IgG1 CH2CH3 extracellular spacer domain, a human CD28 costimulatory domain, and the human CD3ζ signaling domain. We have demonstrated high efficacy of Hu8F4-CAR-T cells against PR1/HLA-A2-expressing cell lines and leukemic blasts from AML patients in vitro. Previous studies have shown that modification of the Fc domains of IgG4 CH2CH3 spacer regions can eliminate activation-induced cell death and off-target killing mediated by mouse Fc gamma receptor (FcgR)-expressing cells. We generated Hu8F4-CAR(PQ) with mutated Fc receptor binding sites on the CH2 domain of Hu8F4-CAR to prevent unwanted interactions with FcgR-expressing cells in vivo . The primary human T cells transduced with Hu8F4-CAR(PQ) can specifically lyse HLA-A2 + PR1-expressing leukemia cell lines in vitro . Furthermore, both adult donor-derived and cord blood-derived Hu8F4-CAR(PQ)-T cells are active and can eliminate U937 leukemia cells in NSG mice. Herein, we demonstrate that modification of the IgG1-based spacer can eliminate Fc receptor-binding-induced adverse effects and Hu8F4-CAR(PQ)-T cells can kill leukemia in vivo .

DOI: https://doi.org/10.21203/rs.3.rs-3937972/v1
Eur J Immunol. 2024 Mar 11. e2350717

Acquired immune resistance is associated with interferon signature and modulation of KLF6/c-MYB transcription factors in myeloid leukemia.

Mubaida Parveen, Beren Karaosmanoglu, Ceren Sucularli, Aysegul Uner, Ekim Z Taskiran, Gunes Esendagli.

  Resistance to immunity is associated with the selection of cancer cells with superior capacities to survive inflammatory reactions. Here, we tailored an ex vivo immune selection model for acute myeloid leukemia (AML) and isolated the residual subpopulations as "immune-experienced" AML (ieAML) cells. We confirmed that upon surviving the immune reactions, the malignant blasts frequently decelerated proliferation, displayed features of myeloid differentiation and activation, and lost immunogenicity. Transcriptomic analyses revealed a limited number of commonly altered pathways and differentially expressed genes in all ieAML cells derived from distinct parental cell lines. Molecular signatures predominantly associated with interferon and inflammatory cytokine signaling were enriched in the AML cells resisting the T-cell-mediated immune reactions. Moreover, the expression and nuclear localization of the transcription factors c-MYB and KLF6 were noted as the putative markers for immune resistance and identified in subpopulations of AML blasts in the patients' bone marrow aspirates. The immune modulatory capacities of ieAML cells lasted for a restricted period when the immune selection pressure was omitted. In conclusion, myeloid leukemia cells harbor subpopulations that can adapt to the harsh conditions established by immune reactions, and a previous "immune experience" is marked with IFN signature and may pave the way for susceptibility to immune intervention therapies.

Keywords:  Immune response; Immunotherapy; Inflammation; Interferon; T cell

DOI:  https://doi.org/10.1002/eji.202350717
bioRxiv. 2024 Feb 28. pii: 2024.02.24.581887. [Epub ahead of print]

cMPL-Based Purification and Depletion of Human Hematopoietic Stem Cells: Implications for Pre-Transplant Conditioning.

Daisuke Araki, Sogun Hong, Nathaniel Linde, Bryan Fisk, Neelam Redekar, Christi Salisbury-Ruf, Allen Krouse, Theresa Engels, Justin Golomb, Pradeep Dagur, Diogo M Magnani, Zhirui Wang, Andre Larochelle.

The transplantation of gene-modified autologous hematopoietic stem and progenitor cells (HSPCs) offers a promising therapeutic approach for hematological and immunological disorders. However, this strategy is often limited by the toxicities associated with traditional conditioning regimens. Antibody-based conditioning strategies targeting cKIT and CD45 antigens have shown potential in mitigating these toxicities, but their long-term safety and efficacy in clinical settings require further validation. In this study, we investigate the thrombopoietin (TPO) receptor, cMPL, as a novel target for conditioning protocols. We demonstrate that high surface expression of cMPL is a hallmark feature of long-term repopulating hematopoietic stem cells (LT-HSCs) within the adult human CD34+ HSPC subset. Targeting the cMPL receptor facilitates the separation of human LT-HSCs from mature progenitors, a delineation not achievable with cKIT. Leveraging this finding, we developed a cMPL-targeting immunotoxin, demonstrating its ability to selectively deplete host cMPL high LT-HSCs with a favorable safety profile and rapid clearance within 24 hours post-infusion in rhesus macaques. These findings present significant potential to advance our understanding of human hematopoiesis and enhance the therapeutic outcomes of ex vivo autologous HSPC gene therapies.Abstract Figure:

DOI: https://doi.org/10.1101/2024.02.24.581887
Leuk Res. 2024 Feb 27. pii: S0145-2126(24)00034-1. [Epub ahead of print]139 107468

Efficacy and safety of mitoxantrone, etoposide, and cytarabine for treatment of relapsed or refractory acute myeloid leukemia.

Sharon Zhong, Heena Kurish, Robert Walchack, Hong Li, Jessi Edwards, Abhay Singh, Anjali Advani.

  BACKGROUND/RATIONALE: Most patients with acute myeloid leukemia (AML) develop relapsed or refractory (R/R) disease after receiving initial induction chemotherapy. Salvage chemotherapy followed by allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only curative therapy for R/R AML. Mitoxantrone, etoposide, and cytarabine (MEC) is the current standard of care salvage regimen for R/R AML at Cleveland Clinic. The primary objective was to determine the overall remission rate (ORR: defined as patients achieving complete remission (CR) or complete remission with incomplete hematologic recovery (CRi)) in R/R AML patients who received MEC.METHODS: Adult patients with R/R AML treated with MEC between July 1, 2014 and September 30, 2022 were included. ORR and its association with baseline characteristics were determined. Secondary outcomes included overall survival (OS), event-free survival (EFS), relapse-free survival (RFS), and safety.
RESULTS: Sixty patients were evaluated. The ORR was 51.7% (33.3% CR and 18.3% CRi). The median time from receipt of MEC to CR/CRi was 7.7 weeks. Patients with bone marrow blasts ≤20% and peripheral blood blasts ≤30% at MEC initiation were more than twice as likely to achieve CR/CRi compared to those with a higher blast burden. The median OS was 6.3 months. Twenty-four (40.0%) patients proceeded to alloHSCT. Twenty-one (35.0%) patients were transferred to the intensive care unit (ICU) during their admission.
CONCLUSIONS: MEC is an effective salvage regimen for patients with R/R AML, especially among those with low disease burden at initiation. Febrile neutropenia, infections, and severe oral mucositis were common with MEC administration.

Keywords:  Acute myeloid leukemia; Cytarabine; Etoposide; Mitoxantrone; Salvage therapy

DOI:  https://doi.org/10.1016/j.leukres.2024.107468
Hemasphere. 2024 Mar;8(3): e44

IDALLO study: A retrospective multicenter study of the SFGM-TC evaluating the efficacy and safety of ivosidenib in relapsed IDH1-mutated AML after allogeneic hematopoietic cell transplantation.

Adrien Caillet, Marion Simonet-Boissard, Edouard Forcade, Marie Robin, Marie-Thérèse Rubio, Marie-Anne Couturier, Micha Srour, Natacha Maillard, Raynier Devillier, Anne Huynh, Jean-Henri Bourhis, Célestine Simand, Sylvain Chantepie, Cyril Boisson, Marie Kroemer, Eric Deconinck, Ana Berceanu.

DOI: https://doi.org/10.1002/hem3.44
Br J Haematol. 2024 Mar 10.

Treatment of refractory/relapsed Diamond-Blackfan anaemia with eltrombopag.

Brynn B Duncan, Jennifer L Lotter, Jeanine Superata, Ma Evette Barranta, Tania Machado, Ivana Darden, Sanjay Venugopal, Colin O Wu, Janis L Abkowitz, Cynthia E Dunbar, David J Young.

  Diamond-Blackfan anaemia (DBA) is a rare, inherited bone marrow failure syndrome with a ribosomal defect causing slowed globin chain production with normal haem synthesis, causing an overabundance of reactive iron/haem and erythroid-specific cellular toxicity. Eltrombopag, a non-peptide thrombopoietin receptor agonist, is a potent intracellular iron chelator and induced a robust durable response in an RPS19-mutated DBA patient on another trial. We hypothesized eltrombopag would improve RBC production in DBA patients. We conducted a single-centre, single-arm pilot study (NCT04269889) assessing safety and erythroid response of 6 months of daily, fixed-dose eltrombopag for DBA patients. Fifteen transfusion-dependent (every 3-5 weeks) patients (median age 18 [range 2-56]) were treated. One responder had sustained haemoglobin improvement and >50% reduction in RBC transfusion frequency. Of note, 7/15 (41%) patients required dose reductions or sustained discontinuation of eltrombopag due to asymptomatic thrombocytosis. Despite the low response rate, eltrombopag has now improved erythropoiesis in several patients with DBA with a favourable safety profile. Dosing restrictions due to thrombocytosis may cause insufficient iron chelation to decrease haem production and improve anaemia in most patients. Future work will focus on erythropoiesis dynamics in patients and use of haem synthesis inhibitors without an impact on other haematopoietic lineages.

Keywords:  Diamond-Blackfan anaemia; chelation; eltrombopag

DOI:  https://doi.org/10.1111/bjh.19357
Res Sq. 2024 Feb 23. pii: rs.3.rs-3889456. [Epub ahead of print]

Active site remodeling in tumor-relevant IDH1 mutants drives distinct kinetic features and potential resistance mechanisms.

Christal Sohl, Matthew Mealka, Nicole Sierra, Diego Matteo, Elene Albekioni, Rachel Khoury, Timothy Mai, Brittany Conley, Nalani Coleman, Kaitlyn Sabo, Elizabeth Komives, Andrey Bobkov, Andrew Cooksy, Steve Silletti, Jamie Schiffer, Tom Huxford.

Mutations in human isocitrate dehydrogenase 1 (IDH1) drive tumor formation in a variety of cancers by replacing its conventional activity with a neomorphic activity that generates an oncometabolite. Little is understood of the mechanistic differences among tumor-driving IDH1 mutants. We previously reported that the R132Q mutant uniquely preserves conventional activity while catalyzing robust oncometabolite production, allowing an opportunity to compare these reaction mechanisms within a single active site. Here, we employed static and dynamic structural methods and found that, compared to R132H, the R132Q active site adopted a conformation primed for catalysis with optimized substrate binding and hydride transfer to drive improved conventional and neomorphic activity over R132H. This active site remodeling revealed a possible mechanism of resistance to selective mutant IDH1 therapeutic inhibitors. This work enhances our understanding of fundamental IDH1 mechanisms while pinpointing regions for improving inhibitor selectivity.

DOI: https://doi.org/10.21203/rs.3.rs-3889456/v1
Am J Hematol. 2024 Mar 14.

JAK inhibitor treatment-resistant splenomegaly before transplantation in myelofibrosis: Splenectomy or radiotherapy?

Maria Chiara Finazzi, Ayalew Tefferi, Alessandro Rambaldi.

DOI: https://doi.org/10.1002/ajh.27292
JCO Precis Oncol. 2024 Mar;8 e2300593

Investigation of Serum Albumin as a Dynamic Treatment-Specific Surrogate for Outcomes in Patients With Myelofibrosis Treated With Ruxolitinib.

Andrew T Kuykendall, Somedeb Ball, Barbara Mora, Qianxing Mo, Najla Al Ali, Margherita Maffioli, Giuseppi Auteri, Camilla Mazzoni, Giuseppe A Palumbo, Andrea Duminuco, Anna Longo, Elena M Elli, Francesco Passamonti, Francesca Palandri, Rami Komrokji.

PURPOSE: Ruxolitinib improves splenomegaly and disease-related symptoms in most patients with myelofibrosis (MF), and it has been associated with a survival benefit in higher-risk patients with splenomegaly. Spleen volume reduction has been associated with a survival benefit in ruxolitinib-treated patients; however, its use as a surrogate is limited. We hypothesized that an anti-inflammatory response to ruxolitinib would correlate with improved patient outcomes.METHODS: We interrogated serum albumin, an acute phase reactant and marker of nutritional status in 590 patients with MF and analyzed differential trajectories of albumin on the basis of ruxolitinib treatment. Additionally, we assessed the prognostic role of baseline albumin and change in albumin.
RESULTS: We found that serum albumin levels tend to decrease in patients with MF; however, this tendency is abrogated by ruxolitinib treatment. To that end, baseline serum albumin level correlates with overall survival (OS) in patients with MF, independent of the variables that comprise the dynamic international prognostic scoring system; however, this correlation is limited to ruxolitinib-naïve patients. In ruxolitinib-treated patients, the change in serum albumin after ruxolitinib treatment, rather than the baseline value, is associated with improved OS, a finding not seen in ruxolitinib-naïve patients.
CONCLUSION: These findings suggest that serum albumin, a ubiquitously available laboratory value, has specific relevance in patients with MF and reflects therapeutic response to ruxolitinib.

DOI: https://doi.org/10.1200/PO.23.00593
Intensive Care Med. 2024 Mar 11.

Long-term survival and functional outcomes of critically ill patients with hematologic malignancies: a Canadian multicenter prospective study.

Laveena Munshi, Guillaume Dumas, Bram Rochwerg, Farah Shoukat, Michael Detsky, Dean A Fergusson, Bruno L Ferreyro, Paul Heffernan, Margaret Herridge, Sheldon Magder, Mark Minden, Rakesh Patel, Salman Qureshi, Aaron Schimmer, Santhosh Thyagu, Han Ting Wang, Sangeeta Mehta.

  PURPOSE: Patients with hematologic malignancy (HM) commonly develop critical illness. Their long-term survival and functional outcomes have not been well described.METHODS: We conducted a prospective, observational study of HM patients admitted to seven Canadian intensive care units (ICUs) (2018-2020). We followed survivors at 7 days, 6 months and 12 months following ICU discharge. The primary outcome was 12-month survival. We evaluated functional outcomes at 6 and 12 months using the functional independent measure (FIM) and short form (SF)-36 as well as variables associated with 12-month survival.
RESULTS: We enrolled 414 patients including 35% women. The median age was 61 (interquartile range, IQR: 52-69), median Sequential Organ Failure Assessment (SOFA) score was 9 (IQR: 6-12), and 22% had moderate-severe frailty (clinical frailty scale [CFS] ≥ 6). 51% had acute leukemia, 38% lymphoma/multiple myeloma, and 40% had received a hematopoietic stem cell transplant (HCT). The most common reasons for ICU admission were acute respiratory failure (50%) and sepsis (40%). Overall, 203 (49%) were alive 7 days post-ICU discharge (ICU survivors). Twelve-month survival of the entire cohort was 21% (43% across ICU survivors). The proportion of survivors with moderate-severe frailty was 42% (at 7 days), 14% (6 months), and 8% (12 months). Median FIM at 7 days was 80 (IQR: 50-109). Physical function, pain, social function, mental health, and emotional well-being were below age- and sex-matched population scores at 6 and 12 months. Frailty, allogeneic HCT, kidney injury, and cardiac complications during ICU were associated with lower 12- month survival.
CONCLUSIONS: 49% of all HM patients were alive at 7 days post-ICU discharge, and 21% at 12 months. Survival varied based upon hematologic diagnosis and frailty status. Survivors had important functional disability and impairment in emotional, physical, and general well-being.

Keywords:  Hematologic malignancy; Immunocompromised; Long-term outcomes

DOI:  https://doi.org/10.1007/s00134-024-07349-z
Nature. 2024 Mar 13.

Mitochondrial complex I activity in microglia sustains neuroinflammation.

L Peruzzotti-Jametti, C M Willis, G Krzak, R Hamel, L Pirvan, R-B Ionescu, J A Reisz, H A Prag, M E Garcia-Segura, V Wu, Y Xiang, B Barlas, A M Casey, A M R van den Bosch, A M Nicaise, L Roth, G R Bates, H Huang, P Prasad, A E Vincent, C Frezza, C Viscomi, G Balmus, Z Takats, J C Marioni, A D'Alessandro, M P Murphy, I Mohorianu, S Pluchino.

Sustained smouldering, or low-grade activation, of myeloid cells is a common hallmark of several chronic neurological diseases, including multiple sclerosis1. Distinct metabolic and mitochondrial features guide the activation and the diverse functional states of myeloid cells2. However, how these metabolic features act to perpetuate inflammation of the central nervous system is unclear. Here, using a multiomics approach, we identify a molecular signature that sustains the activation of microglia through mitochondrial complex I activity driving reverse electron transport and the production of reactive oxygen species. Mechanistically, blocking complex I in pro-inflammatory microglia protects the central nervous system against neurotoxic damage and improves functional outcomes in an animal disease model in vivo. Complex I activity in microglia is a potential therapeutic target to foster neuroprotection in chronic inflammatory disorders of the central nervous system3.

DOI: https://doi.org/10.1038/s41586-024-07167-9
Hepatology. 2024 Mar 11.

Impact of clonal hematopoiesis of indeterminate potential on hepatocellular carcinoma in individuals with steatotic liver disease.

EPIDEMIC Study Investigators

BACKGROUND AIMS: Metabolic dysfunction associated steatotic liver disease (MASLD) is a global epidemic and is the most rapidly rising cause of hepatocellular carcinoma (HCC). Clonal hematopoiesis of indeterminate potential (CHIP) contributes to neoplastic and cardiometabolic disorders and is considered a harbinger of tissue inflammation. CHIP was recently associated with increased risk of liver disease. The aim of this study was to examine whether CHIP is associated with HCC development in patients with SLD.METHODS: We considered individuals with MASLD-HCC (n=208) and controls with (n=414) and without (n=259) advanced fibrosis who underwent whole exome sequencing. CHIP was diagnosed when ≥2 variant callers identified a known myeloid mutation with VAF ≥2%.
RESULTS: CHIP was observed in 116 participants (13.1%), most frequently in DNMT3A, TET2, TP53 and ASXL1, and correlated with age (p<0.0001) and advanced liver fibrosis (p=0.001). Higher AST levels predicted non-DNMT3A-CHIP, in particular with variant allele frequency (VAF)≥10% (OR 1.14, 1.03-1.28 and OR 1.30, 1.12-1.49, respectively, p<0.05). After adjustment for sex, diabetes and a polygenic risk score of inherited MASLD predisposition CHIP was associated with cirrhosis (2.00, 1.30-3.15, p=0.02), and with HCC even after further adjustment for cirrhosis (OR 1.81, 1.11-2.00, 1.30-3.15, p=0.002). Despite the strong collinearity among aging and development of CHIP and HCC, non-DNTM3A-CHIP and TET2 lesions remained associated with HCC after full correction for clinical/genetics covariates and age (OR 2.45, 1.35-4.53; OR 4.8, 1.60-17.0, p=0.02).
CONCLUSIONS: We observed an independent association between CHIP, particularly related to non-DNTM3A and TET2 genetic lesions, and MASLD-HCC.

DOI: https://doi.org/10.1097/HEP.0000000000000839
Br J Haematol. 2024 Mar 11.

Capture-based targeted sequencing using a T-cell control in myeloid malignancies and idiopathic cytopenias.

Grzegorz Pietka, Corinne De Lord, Gwynn Matthias, Betty Cheung, Sangeeta Atwal, Michelle Furtado, Jonathan Cullis, Liz Grey-Davies, Srinivasan Narayanan, Andrew McGregor, Mari Kilner, Jenny Bosworth, Mary Frances McMullin, Thomas Coats, Agapi Parcharidou, Jamie Cavenagh, Jenny Byrne, Sunil Iyengar, Kabir Mohammed, Nicholas Cross, Mike Hubank, Sara Ribeiro, Jamshid Khorashad, Dorte Wren, Simon O'Connor, David Taussig.

  We report on a study of next-generation sequencing in 257 patients undergoing investigations for cytopenias. We sequenced bone marrow aspirates using a target enrichment panel comprising 82 genes and used T cells from paired blood as a control. One hundred and sixty patients had idiopathic cytopenias, 81 had myeloid malignancies and 16 had lymphoid malignancies or other diagnoses. Forty-seven of the 160 patients with idiopathic cytopenias had evidence of somatic pathogenic variants consistent with clonal cytopenias. Only 39 genes of the 82 tested were mutated in the 241 patients with either idiopathic cytopenias or myeloid neoplasms. We confirm that T cells can be used as a control to distinguish between germline and somatic variants. The use of paired analysis with a T-cell control significantly reduced the time molecular scientists spent reporting compared to unpaired analysis. We identified somatic variants of uncertain significance (VUS) in a higher proportion (24%) of patients with myeloid malignancies or clonal cytopenias compared to less than 2% of patients with non-clonal cytopenias. This suggests that somatic VUS are indicators of a clonal process. Lastly, we show that blood depleted of lymphocytes can be used in place of bone marrow as a source of material for sequencing.

Keywords:  T-cell control; germline control; idiopathic cytopenia; myelodysplastic syndrome; next-generation sequencing; variant of unknown significance

DOI:  https://doi.org/10.1111/bjh.19377
Blood Adv. 2024 Mar 11. pii: bloodadvances.2024012669. [Epub ahead of print]

Combined Effect of Unrelated Donor Age and HLA Peptide-Binding Motifs (PBM) Match Status on HCT Outcomes.

Rohtesh S Mehta, Effie W Petersdorf, Stephen R Spellman, Stephanie J Lee.

An HLA-mismatched unrelated donor (MMUD) who is class I protein binding motifs (PBM)-matched is preferred over a PBM-mismatched donor. We hypothesized that using a younger donor (<35 years vs >35 years) could compensate for the inferior overall survival (OS) associated with PBM-mismatches. We compared six groups: HLA-matched/younger donor (n=10,531), HLA-matched/older donor (n=3572), PBM-matched/younger donor (n=357), PBM-matched/older donor (n=257), PBM-mismatched/younger donor (n=616), and PBM-mismatched/older donor (n=339) in patients undergoing transplantation with conventional graft-versus-host disease (GVHD) prophylaxis. In multivariate analysis, HLA-matched/younger donors were associated with superior OS relative to any other group. Pairwise comparisons showed that donor age significantly impacted OS in both HLA-matched and HLA-mismatched groups. Moreover, younger donors appeared to negate the detrimental effect of PBM-mismatching: the PBM-matched/younger donor group had similar OS as the HLA-matched/older donor group and the PBM-mismatched/younger donor group had similar OS as the PBM-matched/older donor group. Our study suggests that older unrelated donor age and PBM-mismatching confer similarly adverse effects on OS and the impacts are additive - a finding which may widen the "acceptable" donor pool. The best OS is observed with HLA-matched/younger donors and the worst with PBM-mismatched/older donors. These findings should be validated with other datasets and with post-transplantation cyclophosphamide-based prophylaxis.

DOI: https://doi.org/10.1182/bloodadvances.2024012669
Leuk Res. 2024 Mar 11. pii: S0145-2126(24)00047-X. [Epub ahead of print]139 107481

Efficacy and safety of bosutinib in patients treated with prior imatinib and/or dasatinib and/or nilotinib: Subgroup analyses from the phase 4 BYOND study.

B Douglas Smith, Tim H Brümmendorf, Gail J Roboz, Carlo Gambacorti-Passerini, Aude Charbonnier, Andrea Viqueira, Eric Leip, Simon Purcell, Erinn Hoag Goldman, Francis Giles, Thomas Ernst, Andreas Hochhaus, Gianantonio Rosti.

  The BYOND study evaluated the efficacy and safety of bosutinib 500 mg once daily in patients with chronic myeloid leukemia (CML) resistant/intolerant to prior tyrosine kinase inhibitors (TKIs). These post-hoc analyses assessed the efficacy and safety of bosutinib by resistance or intolerance to prior TKIs (imatinib-resistant vs dasatinib/nilotinib-resistant vs TKI-intolerant), and cross-intolerance between bosutinib and prior TKIs (imatinib, dasatinib, nilotinib), in patients with Philadelphia chromosome-positive chronic phase CML. Data are reported after ≥3 years' follow-up. Of 156 patients with Philadelphia chromosome-positive chronic phase CML, 53 were imatinib-resistant, 29 dasatinib/nilotinib-resistant, and 74 intolerant to all prior TKIs; cumulative complete cytogenetic response rates at any time were 83.7%, 61.5%, and 86.8%, and cumulative major molecular response rates at any time were 72.9%, 40.7%, and 82.4%, respectively. Of 141, 95, and 79 patients who received prior imatinib, dasatinib, and nilotinib, 64 (45.4%), 71 (74.7%), and 60 (75.9%) discontinued the respective TKI due to intolerance; of these, 2 (3.1%), 5 (7.0%), and 0 had cross-intolerance with bosutinib. The response rates observed in TKI-resistant and TKI-intolerant patients, and low cross-intolerance between bosutinib and prior TKIs, further support bosutinib use for patients with Philadelphia chromosome-positive chronic phase CML resistant/intolerant to prior TKIs. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02228382.

Keywords:  Bosutinib; Chronic myeloid leukemia; Tyrosine kinase inhibitors

DOI:  https://doi.org/10.1016/j.leukres.2024.107481
Elife. 2024 Mar 15. pii: RP90993. [Epub ahead of print]12

Metabolic reprogramming of cancer cells by JMJD6-mediated pre-mRNA splicing associated with therapeutic response to splicing inhibitor.

Carolyn M Jablonowski, Waise Quarni, Shivendra Singh, Haiyan Tan, Dhanushka Hewa Bostanthirige, Hongjian Jin, Jie Fang, Ti-Cheng Chang, David Finkelstein, Ji-Hoon Cho, Dongli Hu, Vishwajeeth Pagala, Sadie Miki Sakurada, Shondra M Pruett-Miller, Ruoning Wang, Andrew Murphy, Kevin Freeman, Junmin Peng, Andrew M Davidoff, Gang Wu, Jun Yang.

  Dysregulated pre-mRNA splicing and metabolism are two hallmarks of MYC-driven cancers. Pharmacological inhibition of both processes has been extensively investigated as potential therapeutic avenues in preclinical and clinical studies. However, how pre-mRNA splicing and metabolism are orchestrated in response to oncogenic stress and therapies is poorly understood. Here, we demonstrate that jumonji domain containing 6, arginine demethylase, and lysine hydroxylase, JMJD6, acts as a hub connecting splicing and metabolism in MYC-driven human neuroblastoma. JMJD6 cooperates with MYC in cellular transformation of murine neural crest cells by physically interacting with RNA binding proteins involved in pre-mRNA splicing and protein homeostasis. Notably, JMJD6 controls the alternative splicing of two isoforms of glutaminase (GLS), namely kidney-type glutaminase (KGA) and glutaminase C (GAC), which are rate-limiting enzymes of glutaminolysis in the central carbon metabolism in neuroblastoma. Further, we show that JMJD6 is correlated with the anti-cancer activity of indisulam, a 'molecular glue' that degrades splicing factor RBM39, which complexes with JMJD6. The indisulam-mediated cancer cell killing is at least partly dependent on the glutamine-related metabolic pathway mediated by JMJD6. Our findings reveal a cancer-promoting metabolic program is associated with alternative pre-mRNA splicing through JMJD6, providing a rationale to target JMJD6 as a therapeutic avenue for treating MYC-driven cancers.

Keywords:  GLS; JMJD6; cancer biology; indisulam; neuroblastoma; none; splicing

DOI:  https://doi.org/10.7554/eLife.90993
Science. 2024 Mar 15. 383(6688): eadk4422

Continuous evolution of compact protein degradation tags regulated by selective molecular glues.

Jaron A M Mercer, Stephan J DeCarlo, Shourya S Roy Burman, Vedagopuram Sreekanth, Andrew T Nelson, Moritz Hunkeler, Peter J Chen, Katherine A Donovan, Praveen Kokkonda, Praveen K Tiwari, Veronika M Shoba, Arghya Deb, Amit Choudhary, Eric S Fischer, David R Liu.

Conditional protein degradation tags (degrons) are usually >100 amino acids long or are triggered by small molecules with substantial off-target effects, thwarting their use as specific modulators of endogenous protein levels. We developed a phage-assisted continuous evolution platform for molecular glue complexes (MG-PACE) and evolved a 36-amino acid zinc finger (ZF) degron (SD40) that binds the ubiquitin ligase substrate receptor cereblon in complex with PT-179, an orthogonal thalidomide derivative. Endogenous proteins tagged in-frame with SD40 using prime editing are degraded by otherwise inert PT-179. Cryo-electron microscopy structures of SD40 in complex with ligand-bound cereblon revealed mechanistic insights into the molecular basis of SD40's activity and specificity. Our efforts establish a system for continuous evolution of molecular glue complexes and provide ZF tags that overcome shortcomings associated with existing degrons.

DOI: https://doi.org/10.1126/science.adk4422