bims-tremyl Biomed News
on Therapy resistance biology in myeloid leukemia
Issue of 2022‒04‒24
38 papers selected by
Paolo Gallipoli
Barts Cancer Institute, Queen Mary University of London

  1. Blood. 2022 Apr 20. pii: blood.2021013277. [Epub ahead of print]
      Inducing cell death by the sphingolipid ceramide is a potential anti-cancer strategy, but the underlying mechanisms remain poorly defined. Here, we show that triggering accumulation of ceramide in acute myeloid leukaemia (AML) cells by inhibition of sphingosine kinase induces an apoptotic integrated stress response (ISR) through protein kinase R-mediated activation of the master transcription factor ATF4. This leads to transcription of the BH3-only protein, Noxa, and degradation of the pro-survival Mcl-1 protein on which AML cells are highly dependent on for survival. Targeting this novel ISR pathway in combination with the Bcl-2 inhibitor venetoclax synergistically killed primary AML blasts, including those with venetoclax-resistant mutations, as well as immunophenotypic leukemic stem cells, and reduced leukemic engraftment in patient-derived AML xenografts. Collectively, these findings provide mechanistic insight into the anti-cancer effects of ceramide and pre-clinical evidence for new approaches to augment Bcl-2 inhibition in the therapy of AML and other cancers with high Mcl-1 dependency.
  2. Blood. 2022 Apr 20. pii: blood.2021015328. [Epub ahead of print]
      DDX41 germline mutations (DDX41MutGL) are the most common genetic predisposition to myelodysplastic syndrome and acute myeloid leukemia (AML). Recent reports suggest that DDX41MutGL myeloid malignancies could be considered as a distinct entity, even if their specific presentation and outcome remain to be defined. We described here the clinical and biological features of 191 patients with DDX41MutGL AML. Baseline characteristics and outcome of 86 of them, treated with intensive chemotherapy in 5 prospective ALFA/FILO trials were compared with those of 1604 DDX41 wild-type (DDX41WT) AML patients, representing a prevalence of 5%. DDX41MutGL AML patients were mostly males (75%) in their seventh decade, with low leukocyte count (median, 2x109/L), low bone marrow blast infiltration (median, 33%), normal cytogenetics (75%) and few additional somatic mutations (median, 2). A second somatic DDX41 mutation (DDX41MutSom) was found in 82% of patients and clonal architecture inference suggested that it could be the main driver for AML progression. DDX41MutGL patients displayed higher complete remission (CR) rates (94% vs. 69%, p<0.0001) and longer restricted mean overall survival (OS) censored at hematopoietic stem cell transplantation (HSCT) than ELN-2017 intermediate/adverse (Int/Adv) DDX41WT patients (5-year ΔRMST of 13.6 months, p < 0.001). Relapse rates censored at HSCT were lower at 1 year in DDX41MutGL patients (15% vs. 44%) but later increased to join that of Int/Adv DDX41WT patients at 3 years (82% vs 75%). HSCT in first CR was associated with prolonged relapse-free survival (RFS; HR, 0.43 [95%CI, 0.21-0.88]; p = 0.02) but not with longer OS (HR=0.77 [95%CI, 0.35-1.68], p=0.5).
  3. Antioxidants (Basel). 2022 Apr 05. pii: 717. [Epub ahead of print]11(4):
      Acute myeloid leukemia (AML) is a molecularly heterogenous hematological malignancy, with one of the most common mutations being internal tandem duplication (ITD) of the juxtamembrane domain of the fms-like tyrosine kinase receptor-3 (FLT3). Despite the development of FLT3-directed tyrosine kinase inhibitors (TKI), relapse and resistance are problematic, requiring improved strategies. In both patient samples and cell lines, FLT3-ITD raises levels of reactive oxygen species (ROS) and elicits an antioxidant response which is linked to chemoresistance broadly in AML. NF-E2-related factor 2 (NRF2) is a transcription factor regulating the antioxidant response including heme oxygenase -1 (HO-1), a heat shock protein implicated in AML resistance. Here, we demonstrate that HO-1 is elevated in FLT3-ITD-bearing cells compared to FLT3-wild type (WT). Transient knockdown or inhibitor-based suppression of HO-1 enhances vulnerability to the TKI, quizartinib, in both TKI-resistant and sensitive primary AML and cell line models. NRF2 suppression (genetically or pharmacologically using brusatol) results in decreased HO-1, suggesting that TKI-resistance is dependent on an active NRF2-driven pathway. In AML-patient derived xenograft (PDX) models, brusatol, in combination with daunorubicin, reduces leukemia burden and prolongs survival. Cumulatively, these data encourage further development of brusatol and NRF2 inhibition as components of combination therapy for refractory AML.
    Keywords:  AML; FLT3-ITD; HO-1; NRF2; TKI resistance
  4. Sci Signal. 2022 Apr 19. 15(730): eabl7989
      Most tumor types either fail to respond or become resistant to kinase inhibitors, often because of compensatory prosurvival pathways in the cancer cell's broader signaling circuitry. Here, we found that intrinsic resistance to kinase inhibitors in cultured primary acute myeloid leukemia (AML) cells may be overcome by reshaping kinase networks into topologies that confer drug sensitivity. We identified several antagonists of chromatin-modifying enzymes that sensitized AML cell lines to kinase inhibitors. Of these, we confirmed that inhibitors of the lysine-specific demethylase (LSD1; also known as KDM1A) rewired kinase signaling in AML cells in a way that increased the activity of the kinase MEK and that broadly suppressed the activity of other kinases and feedback loops. As a result, AML cell lines and about half of primary human AML samples were primed for sensitivity to the MEK inhibitor trametinib. Primary human cells with KRAS mutations and those with high MEK pathway activity were the best responders to sequential treatment with LSD1 inhibitors then trametinib, whereas those with NRAS mutations and high mTOR activity were poor responders. Overall, our study reveals the MEK pathway as a mechanism of resistance to LSD1 inhibitors in AML and shows a way to modulate kinase network circuitry to potentially overcome therapeutic resistance to kinase inhibitors.
  5. Bio Protoc. 2022 Mar 20. 12(6): e4353
      Ex vivo culture of primary acute myeloid leukemia (AML) cells is notoriously difficult due to spontaneous differentiation and cell death, which hinders mechanistic and translational studies. To overcome this bottleneck, we have implemented a co-culture system, where the OP9-M2 stromal cells support the growth, but most notably limit the differentiation of primary AML cells, thus allowing for mechanistic studies in vitro. Additionally, the co-culture on OP9-M2 stromal is superior in preserving surface marker expression of primary (adult and pediatric) AML cells in comparison to stroma-free culture. Thus, by combining the co-culture with multicolor, high-throughput FACS, we can evaluate the effect of hundreds of small molecules on multi-parametric processes including: cell survival, stemness (leukemic stem cells), and myeloid differentiation on the primary AML cells at a single-cell level. This method streamlines the identification of potential therapeutic agents, but also facilitates combinatorial screening aiming, for instance, at dissecting the regulatory pathways in a patient-specific manner. Graphic abstract: Schematic representation of the ex vivo small molecule screening of primary human acute myeloid leukemia. Irradiated, sub-confluent OP9-M2 stromal cells are plated in half-area 96 wells plates 4-16 h prior to adding primary AML cells. Compounds are added 36-48 h later and effects on cell number, leukemic stem cell population, and myeloid differentiation are quantifed by FACS after 4 days of treatment.
    Keywords:  Drug; FACS; High throughput; Leukemia; Screen; Stem cell
  6. Sci Adv. 2022 Apr 22. 8(16): eabm9987
      Acute myeloid leukemia (AML) arises when leukemia-initiating cells, defined by a primary genetic lesion, acquire subsequent molecular changes whose cumulative effects bypass tumor suppression. The changes that underlie AML pathogenesis not only provide insights into the biology of transformation but also reveal novel therapeutic opportunities. However, backtracking these events in transformed human AML samples is challenging, if at all possible. Here, we approached this question using a murine in vivo model with an MLL-ENL fusion protein as a primary molecular event. Upon clonal transformation, we identified and extensively verified a recurrent codon-changing mutation (Arg295Cys) in the ERM protein moesin that markedly accelerated leukemogenesis. Human cancer-associated moesin mutations at the conserved arginine-295 residue similarly enhanced MLL-ENL-driven leukemogenesis. Mechanistically, the mutation interrupted the stability of moesin and conferred a neomorphic activity to the protein, which converged on enhanced extracellular signal-regulated kinase activity. Thereby, our studies demonstrate a critical role of ERM proteins in AML, with implications also for human cancer.
  7. Leuk Lymphoma. 2022 Apr 20. 1-10
      We conducted a phase Ib/II multi-arm, parallel cohort study to simultaneously evaluate various immunotherapeutic agents and combinations in relapsed/refractory acute myeloid leukemia (AML). Overall, 50 patients were enrolled into one of 6 arms: (A) single agent PF-04518600 (OX40 agonist monoclonal antibody), (B) azacitidine + venetoclax + gemtuzumab ozogamicin (GO), (C) azacitidine + avelumab (anti-PD-L1 monoclonal antibody) + GO, (D) azacitidine + venetoclax + avelumab, (E) azacitidine + avelumab + PF-04518600, and (F) glasdegib + GO. Among all regimens evaluated, azacitidine + venetoclax + GO appeared most promising. In this arm, the CR/CRi rates among venetoclax-naïve and prior venetoclax-exposed patients were 50% and 22%, respectively, and the 1-year OS rate was 31%. This study shows the feasibility of a conducting a multi-arm trial to efficiently and simultaneously evaluate novel therapies in AML, a needed strategy in light of the plethora of emerging therapies. This trial was registered at as NCT03390296.
    Keywords:  Monoclonal antibody; avelumab; azacitidine; gemtuzumab ozogamicin; venetoclax
  8. Blood. 2022 Apr 19. pii: blood.2021015108. [Epub ahead of print]
      Differentiation blockade is a hallmark of AML. Strategy to overcome such blockade is a promising approach against the disease. Lack of understanding underlying mechanisms hampers development of such strategy. Dysregulated ribonucleotide reductase (RNR) is considered a druggable target in proliferative cancers susceptible to deoxynucleoside triphosphates (dNTPs) depletion. Herein, we report an unanticipated discovery that hyperactivating RNR enables differentiation and decreases leukemia cell growth. We integrate pharmacogenomics and metabolomics analyses to identify that pharmacologically (e.g., nelarabine) or genetically upregulating RNR subunit M2 (RRM2) level, creates a dNTP pool imbalance and overcomes differentiation arrest. Moreover, R-loop mediated DNA replication stress signaling is responsible for RRM2 activation by nelarabine treatment. Further aggravating dNTP imbalance by depleting the dNTP hydrolase SAM domain and HD domain-containing protein 1 (SAMHD1) enhances ablation of leukemia stem cells by RRM2 hyperactivation. Mechanistically, excessive activation of ERK signaling downstream of the imbalance contributes to cellular outcomes of RNR hyperactivation. A CRISPR screen identifies a synthetic lethal interaction between loss of DUSP6, an ERK negative regulator, and nelarabine treatment. These data demonstrate that dNTP homeostasis governs leukemia maintenance, and combination of DUSP inhibition and nelarabine represents a therapeutic strategy.
  9. Nat Commun. 2022 Apr 19. 13(1): 2013
      Metabolic programs can differ substantially across genetically distinct subtypes of acute myeloid leukemia (AML). These programs are not static entities but can change swiftly as a consequence of extracellular changes or in response to pathway-inhibiting drugs. Here, we uncover that AML patients with FLT3 internal tandem duplications (FLT3-ITD+) are characterized by a high expression of succinate-CoA ligases and high activity of mitochondrial electron transport chain (ETC) complex II, thereby driving high mitochondrial respiration activity linked to the Krebs cycle. While inhibition of ETC complex II enhances apoptosis in FLT3-ITD+ AML, cells also quickly adapt by importing lactate from the extracellular microenvironment. 13C3-labelled lactate metabolic flux analyses reveal that AML cells use lactate as a fuel for mitochondrial respiration. Inhibition of lactate transport by blocking Monocarboxylic Acid Transporter 1 (MCT1) strongly enhances sensitivity to ETC complex II inhibition in vitro as well as in vivo. Our study highlights a metabolic adaptability of cancer cells that can be exploited therapeutically.
  10. Haematologica. 2022 Apr 21.
      The immune receptor TREM1 (Triggering receptor expressed on myeloid cells 1) is a master regulator of inflammatory response. Compelling evidence suggests important pathological roles for TREM1 in various types of solid tumors. However, the role of TREM1 in hematologic malignancies is not known. Our previous study demonstrates that TREM1 cooperates with diminished DNA damage response to induce expansion of pre-leukemic hematopoietic stem cells (HSCs) in mice deficient for the Fanconi anemia gene Fanca. Here we investigate TREM1 in leukemogenesis using mouse models of the DNA repair-deficient Fanca-/- and the oncogenic MLL-AF9 or KrasG12D. We found that Trem1 was highly expressed in pre-leukemic HSCs and leukemia stem cells (LSCs). By selective deletion of the Trem1 gene in the hematopoietic compartment, we showed that ablation of Trem1 reduced leukemogenic activity of the pre-leukemic HSCs and LSCs in mice. Trem1 was required for the proliferation of the pre-leukemic HSCs and LSCs. Further analysis revealed that Trem1 expression in pre-leukemic HSCs and LSCs was associated with persistent DNA damage, prolonged oncogenic stress, and a strong inflammatory signature. Targeting several top Trem1 inflammatory signatures inhibits the proliferation of pre-leukemic HSCs and LSCs. Collectively, our observations uncover previously unknown expression and function of TREM1 in malignant stem cells, and identify TREM1 as a driver of leukemogenesis.
  11. Front Oncol. 2022 ;12 858202
      There is a deficiency of real-world data on the impact of combining venetoclax (VEN) with hypomethylating agents (HMAs) in newly diagnosed acute myeloid leukemia (AML) patients. We conducted a single-center, propensity-adjusted retrospective cohort study to compare composite complete remission (CCR) rates, median overall survival (m-OS) and median event-free survival (m-EFS). A total of 170 adult AML patients were treated with first-line azacitidine (AZA) or decitabine (DEC) +/- VEN. Median age was 71 years and 99 (58%) were male. Median follow-up in HMA and HMA-VEN groups was 79 and 21 months. Treatments included AZA alone (n=35, 21%), DEC alone (n=84, 49%), AZA-VEN (n=24, 14%) and DEC-VEN (n=27, 16%). VEN improved CCR rates to HMAs overall (52% vs. 27%, P<0.05) and to AZA (54% vs. 10%, P<0.05), but not to DEC (43% vs. 32%, P=0.35); it did not improve OS, and only improved EFS for AZA (10.5 vs. 3.8 months, P<0.05). CCR rates were lower with AZA than with DEC (13% vs. 33%, P<0.05), but OS and EFS were not different statistically. CCR rates did not differ for AZA-VEN vs. DEC-VEN (CCR: 58% vs. 52%, P=0.66), but OS and EFS were longer for AZA-VEN (m-OS: 12.3 vs. 2.2 months, P<0.05; m-EFS: 9.2 vs. 2.1 months, P<0.05). Our analysis showed that combining VEN with AZA in newly diagnosed AML patients improved outcomes, but combining VEN with DEC did not. AZA-VEN was associated with improved outcomes compared to DEC-VEN. Further studies are needed to test the benefit of combining VEN with DEC.
    Keywords:  acute myeloid leukemia; azacitidine; decitabine (451668); event-free survival (EFS); outcomes; overall survival (OS); venetoclax (ABT-199)
  12. Sci Signal. 2022 Apr 19. 15(730): eabo0059
      Mutations in multiple cancers may synergize to alter the cellular epigenetic and transcriptional state and corrupt key signaling pathways. In this issue of Science Signaling, Pedicona et al. illustrate how the two processes intersect to regulate cellular differentiation in acute myeloid leukemia (AML) and show how inhibition of epigenetic regulators promotes sensitivity to kinase inhibitors.
  13. Clin Cancer Res. 2022 Apr 22. pii: clincanres.0279.2022. [Epub ahead of print]
      Two publications detailing the clinical outcomes of patients with acute myeloid leukemia and mutations in IDH1, IDH2, or FLT3 who received initial therapy with venetoclax and azacitidine provide new insights into risk stratification and set the stage for future trials integrating molecularly targeted therapy with this new standard regimen.
  14. Cancers (Basel). 2022 Apr 16. pii: 2025. [Epub ahead of print]14(8):
      Venetoclax (VEN) belongs the BH3-mimetic class that selectively targets BCL-2, activating apoptosis. The combination of VEN and azacitidine (AZA) has changed the paradigm of treatment of newly diagnosed (ND) acute myeloid leukemia (AML) patients ineligible for intensive chemotherapy. There is scarce evidence for the use of VEN-AZA for relapsed or refractory (R/R) AML. We compared the outcome of 39 R/R AML and 38 ND AML patients treated between 01/20 and 12/21. The median age was 69 (22-86) and 73 (61-81) in the R/R and ND groups, respectively. Adverse cytogenetics were found in 36% of patients in the R/R group and 59% of patients in the ND group. Overall response rate was 37% in R/R AML, including 13% CR, 8% CRi, 3% PR and 13% MLFS, and 58% in the ND AML, including 32% CR, 13% CRi and 13% MLFS. Adverse cytogenetics was associated with treatment failure in the R/R group (Relative Risk = 0.13, p = 0.005). Median overall survival (OS) was 5.9 months in the R/R group and 9.4 months in the ND group. Median OS was 2.2 months in the adverse cytogenetics group versus 8.7 months in the intermediate cytogenetics group in the R/R group (p = 0.02). Median leukemia-free survival was not different between the two groups (9.4 months and 10.3 months), indicating that VEN-AZA can be an efficient salvage treatment for selected R/R AML patients. In conclusion, VEN-AZA is a promising treatment for ND AML and for selected R/R AML patients.
    Keywords:  acute myeloid leukemia; venetoclax
  15. Int J Hematol. 2022 Apr 23.
      The curative potential of allogeneic hematopoietic cell transplantation (allo-HCT) for acute myeloid leukemia (AML) relies on the graft-versus-leukemia (GVL)-effect. Relapse after allo-HCT occurs in a considerable proportion of patients, and has a dismal prognosis with very limited curative potential, especially for patients with FLT-ITD-mutated AML. Since the first description of sorafenib for treatment of FLT3-ITD-mutated AML, several clinical trials have tried to determine the efficacy of FLT3 inhibitors for preventing and treating AML relapse after allo-HSCT, but many questions regarding differences among compounds and mechanisms of action remain unanswered. This review provides an overview on the established and evolving use of FLT3 inhibitors to prevent or treat relapse of AML in the context of allo-HCT, focusing on the recently discovered immunogenic potential of some FLT3 inhibitors and addressing the possible mechanisms of leukemia drug-escape.
    Keywords:  Acute myeloid leukemia; Allogeneic hematopoietic stem cell transplantation; FLT3-ITD; Gilteritinib; Midostaurin; Relapse; Sorafebin
  16. Diagnostics (Basel). 2022 Apr 15. pii: 996. [Epub ahead of print]12(4):
      Acute myeloid leukemia (AML) is a haematological neoplasm resulting from the accumulation of genetic and epigenetic alterations. Patients' prognoses vary with AML genetic heterogeneity, which hampers successful treatments. Single-cell approaches have provided new insights of the clonal architecture of AML, revealing the mutational history from diagnosis, during treatment and to relapse. In this review, we imagine single-cell technologies as the Ariadne's thread that will guide us out of the AML maze, provide a precise identikit of the leukemic cell at single-cell resolution and explore genomic, transcriptomic, epigenetic and proteomic levels.
    Keywords:  acute myeloid leukemia; clonal evolution; clonal heterogeneity; single-cell DNA sequencing; single-cell RNA sequencing
  17. N Engl J Med. 2022 04 21. 386(16): 1519-1531
      BACKGROUND: The combination of ivosidenib - an inhibitor of mutant isocitrate dehydrogenase 1 (IDH1) - and azacitidine showed encouraging clinical activity in a phase 1b trial involving patients with newly diagnosed IDH1-mutated acute myeloid leukemia.METHODS: In this phase 3 trial, we randomly assigned patients with newly diagnosed IDH1-mutated acute myeloid leukemia who were ineligible for intensive induction chemotherapy to receive oral ivosidenib (500 mg once daily) and subcutaneous or intravenous azacitidine (75 mg per square meter of body-surface area for 7 days in 28-day cycles) or to receive matched placebo and azacitidine. The primary end point was event-free survival, defined as the time from randomization until treatment failure (i.e., the patient did not have complete remission by week 24), relapse from remission, or death from any cause, whichever occurred first.
    RESULTS: The intention-to-treat population included 146 patients: 72 in the ivosidenib-and-azacitidine group and 74 in the placebo-and-azacitidine group. At a median follow-up of 12.4 months, event-free survival was significantly longer in the ivosidenib-and-azacitidine group than in the placebo-and-azacitidine group (hazard ratio for treatment failure, relapse from remission, or death, 0.33; 95% confidence interval [CI], 0.16 to 0.69; P = 0.002). The estimated probability that a patient would remain event-free at 12 months was 37% in the ivosidenib-and-azacitidine group and 12% in the placebo-and-azacitidine group. The median overall survival was 24.0 months with ivosidenib and azacitidine and 7.9 months with placebo and azacitidine (hazard ratio for death, 0.44; 95% CI, 0.27 to 0.73; P = 0.001). Common adverse events of grade 3 or higher included febrile neutropenia (28% with ivosidenib and azacitidine and 34% with placebo and azacitidine) and neutropenia (27% and 16%, respectively); the incidence of bleeding events of any grade was 41% and 29%, respectively. The incidence of infection of any grade was 28% with ivosidenib and azacitidine and 49% with placebo and azacitidine. Differentiation syndrome of any grade occurred in 14% of the patients receiving ivosidenib and azacitidine and 8% of those receiving placebo and azacitidine.
    CONCLUSIONS: Ivosidenib and azacitidine showed significant clinical benefit as compared with placebo and azacitidine in this difficult-to-treat population. Febrile neutropenia and infections were less frequent in the ivosidenib-and-azacitidine group than in the placebo-and-azacitidine group, whereas neutropenia and bleeding were more frequent in the ivosidenib-and-azacitidine group. (Funded by Agios Pharmaceuticals and Servier Pharmaceuticals; AGILE number, NCT03173248.).
  18. Sci Adv. 2022 Apr 22. 8(16): eabj1664
      MicroRNAs (miRNAs) have been shown to hold prognostic value in acute myeloid leukemia (AML); however, the temporal dynamics of miRNA expression in AML are poorly understood. Using serial samples from a mouse model of AML to generate time-series miRNA sequencing data, we are the first to show that the miRNA transcriptome undergoes state-transition during AML initiation and progression. We modeled AML state-transition as a particle undergoing Brownian motion in a quasi-potential and validated the AML state-space and state-transition model to accurately predict time to AML in an independent cohort of mice. The critical points of the model provided a framework to align samples from mice that developed AML at different rates. Our mathematical approach allowed discovery of dynamic processes involved during AML development and, if translated to humans, has the potential to predict an individual's disease trajectory.
  19. Exp Hematol. 2022 Apr 13. pii: S0301-472X(22)00156-4. [Epub ahead of print]
      The molecular events responsible for decitabine responses in MDS and AML patients are poorly understood. Decitabine has a short serum half-life and limited stability in tissue culture. Therefore, theoretical pharmacologic differences may exist between patient molecular changes in vitro and the consequences of in vivo treatment. To systematically identify the global genomic and transcriptomic alterations induced by decitabine in vivo, we evaluated primary bone marrow samples that were collected during patient treatment and applied whole-genome bisulfite sequencing, RNA-sequencing, and single-cell RNA sequencing. Decitabine induced global, reversible hypomethylation after 10 days of therapy in all patients, which was associated with induction of interferon-induced pathways, the expression of endogenous retroviral elements, and inhibition of erythroid-related transcripts, recapitulating many effects seen previously in in vitro studies. However, at relapse after decitabine treatment, interferon-induced transcripts remained elevated relative to day 0, but erythroid-related transcripts now were more highly expressed than at day 0. Clinical responses were not correlated with epigenetic or transcriptional signatures, although sample size and interpatient variance restricted the statistical power required for capturing smaller effects. Collectively, these data define global hypomethylation by decitabine and find that erythroid-related pathways may be relevant because they are inhibited by therapy and reverse at relapse.
    Keywords:  AML; Decitabine; MDS; endogenous retroelements; maturation
  20. Blood. 2022 Apr 22. pii: blood.2021014485. [Epub ahead of print]
      Acute lymphoblastic leukemia (ALL) is the most common malignant disease affecting children. Although therapy strategies improved, T-cell acute lymphoblastic leukemia (T-ALL) relapse is associated with chemoresistance and a poor prognosis. One strategy to overcome this obstacle is the application of monoclonal antibodies. Here, we show that leukemic cells from T-ALL patients express surface CD38 and CD47, both attractive targets for antibody therapy. We therefore investigated the commercially available CD38 antibody daratumumab (Dara) in combination with a proprietary modified CD47 antibody (Hu5F9-IgG2σ) in vitro and in vivo. Compared to single treatments, this combination significantly increased in vitro antibody-dependent cellular phagocytosis (ADCP) in T-ALL cell lines as well as in random de novo and in relapsed/refractory T-ALL patient derived xenograft (PDX) samples. Similarly, enhanced ADCP was observed when combining Dara with pharmacological inhibition of CD47 interactions using a glutaminyl cyclase inhibitor. Phase II-like preclinical in vivo trials using T-ALL PDX samples in experimental minimal residual disease like (MRD-like) and overt leukemia models revealed a high anti-leukemic efficacy of CD47 blockade alone. However, T-ALL xenograft mice subjected to chemotherapy first (post-chemo MRD) and subsequently co-treated with Dara and Hu5F9-IgG2σ displayed significantly reduced bone marrow infiltration as compared to single treatments. In relapsed and highly refractory T-ALL PDX combined treatment with Dara and Hu5F9-IgG2σ was required to substantially prolong survival as compared to single treatments. These findings suggest that combining CD47 blockade with Dara is a promising therapy for T-ALL, especially for relapsed/refractory disease harbouring a dismal prognosis in patients.
  21. Genes Dev. 2022 Apr 21.
      Genome organization plays a pivotal role in transcription, but how transcription factors (TFs) rewire the structure of the genome to initiate and maintain the programs that lead to oncogenic transformation remains poorly understood. Acute promyelocytic leukemia (APL) is a fatal subtype of leukemia driven by a chromosomal translocation between the promyelocytic leukemia (PML) and retinoic acid receptor α (RARα) genes. We used primary hematopoietic stem and progenitor cells (HSPCs) and leukemic blasts that express the fusion protein PML-RARα as a paradigm to temporally dissect the dynamic changes in the epigenome, transcriptome, and genome architecture induced during oncogenic transformation. We found that PML-RARα initiates a continuum of topologic alterations, including switches from A to B compartments, transcriptional repression, loss of active histone marks, and gain of repressive histone marks. Our multiomics-integrated analysis identifies Klf4 as an early down-regulated gene in PML-RARα-driven leukemogenesis. Furthermore, we characterized the dynamic alterations in the Klf4 cis-regulatory network during APL progression and demonstrated that ectopic Klf4 overexpression can suppress self-renewal and reverse the differentiation block induced by PML-RARα. Our study provides a comprehensive in vivo temporal dissection of the epigenomic and topological reprogramming induced by an oncogenic TF and illustrates how topological architecture can be used to identify new drivers of malignant transformation.
    Keywords:  chromatin; chromatin topology; gene regulation; leukemia
  22. Br J Haematol. 2022 Apr 19.
      In order to improve the outcome observed with azacitidine (AZA) in higher-risk Myelodysplastic syndrome (MDS), its combination with other drugs in MDS must be evaluated. So far, no combination has not been shown to be more effective than AZA alone. AZA-PLUS was a phase II trial that, in a "pick a winner" approach, randomly assigned patients with higher-risk MDS, CMML and low blast count AML to: AZA; AZA plus lenalidomide; AZA plus Valproic Acid or AZA plus Idarubicin. 322 patients were included. After six cycles, 69 (21.4%) CR + PR were observed with no benefit from any combination. Median EFS and OS were 17.2 and 19.7 months in the whole cohort, respectively, with no difference across randomised arms. Infection and rates of hospitalisation during the first six cycles were higher in the AZA-LEN And AZA-IDA arm, related to increased myelosuppression. Factors associated with better response were IPSS, favourable or intermediate karyotype, haemoglobin, lower circulating blast count, fibrinogen level and lower LDH, while poorer survival was seen in therapy-related MDS and, in the case of TP53, PTPN11 or CSF3R mutation. The combinations used did not improve the outcome obtained with AZA alone. However, our "pick a winner" randomised strategy may remain useful with potentially more active drugs to be tested in combination with AZA.
    Keywords:  MDS; clinical trials; molecular biology
  23. Cell Death Dis. 2022 Apr 20. 13(4): 384
      Chronic myeloid leukemia (CML) are initiated and sustained by self-renewing malignant CD34+ stem cells. Extensive efforts have been made to reveal the metabolic signature of the leukemia stem/progenitor cells in genomic, transcriptomic, and metabolomic studies. However, very little proteomic investigation has been conducted and the mechanism regarding at what level the metabolic program was rewired remains poorly understood. Here, using label-free quantitative proteomic profiling, we compared the signature of CD34+ stem/progenitor cells collected from CML individuals with that of healthy donors and observed significant changes in the abundance of enzymes associated with aerobic central carbonate metabolic pathways. Specifically, CML stem/progenitor cells expressed increased tricarboxylic acid cycle (TCA) with decreased glycolytic proteins, accompanying by increased oxidative phosphorylation (OXPHOS) and decreased glycolysis activity. Administration of the well-known OXPHOS inhibitor metformin eradicated CML stem/progenitor cells and re-sensitized CD34+ CML cells to imatinib in vitro and in patient-derived tumor xenograft murine model. However, different from normal CD34+ cells, the abundance and activity of OXPHOS protein were both unexpectedly elevated with endoplasmic reticulum stress induced by metformin in CML CD34+ cells. The four major aberrantly expressed protein sets, in contrast, were downregulated by metformin in CML CD34+ cells. These data challenged the dependency of OXPHOS for CML CD34+ cell survival and underlined the novel mechanism of metformin. More importantly, it suggested a strong rationale for the use of tyrosine kinase inhibitors in combination with metformin in treating CML.
  24. J Geriatr Oncol. 2022 Apr 18. pii: S1879-4068(22)00079-0. [Epub ahead of print]
      INTRODUCTION: Survival benefit associated with intensive over low-intensity chemotherapy in older adults with acute myeloid leukemia (AML) is controversial. Geriatric assessment and genetic risk categories correlate with survival following intensive chemotherapy in older adults with AML and can guide treatment selection.MATERIALS AND METHODS: In a single-center trial, we integrated both geriatric assessment, and genetic risk categories to personalize selection of intensive versus low-intensity chemotherapy in older adults ≥60 years with AML (NCT03226418). In the present report, we demonstrate feasibility of this approach.
    RESULTS: Broad eligibility criteria and co-management of patients with community oncologists allowed enrollment of 45% of all patients with AML treated at our center during the study period. The median time from enrollment to therapy initiation was two days (range 0-9). Over half of the trial patients had a score of ≥3 on hematopoietic cell transplantation comorbidity index, impairment in physical function (Short Physical Performance Battery), and Montreal Cognitive Assessment. Three fit patients received intensive chemotherapy, whereas other patients received low-intensity chemotherapy. Mortality at 30 days from diagnosis was 3.7% (95% confidence interval [CI] 0.7-18.3%) and at 90 days was 29.6% (95% CI 15.9-48.5%). One-year overall survival was 66% (95% CI 60-87%).
    DISCUSSION: Our data demonstrate the feasibility of integrating geriatric assessment in precision oncology trials to define fitness for intensive chemotherapy. Broad eligibility criteria and academic-community collaboration can expand access to clinical trials.
    Keywords:  Acute myeloid leukemia; Chemotherapy; Clinical trial; Geriatric assessment; Precision-oncology
  25. Cell Death Dis. 2022 Apr 20. 13(4): 379
      Venetoclax plus cytarabine therapy is approved for elderly acute myeloid leukemia (AML) patients and needs further improvement. We studied the mechanisms of venetoclax plus cytarabine treatment and searched for a third agent to enhance their effects. Cytarabine induces S phase arrest-mediated DNA damage with activation of DNA replication checkpoint kinase 1 (Chk1) through phosphorylation, while venetoclax induces B cell lymphoma 2 (Bcl-2)-interacting mediator of cell death (Bim)-mediated apoptotic DNA damage. Myeloid cell leukemia-1 (Mcl-1) plays negative roles in both events by sequestering Bim and accelerating Chk1 phosphorylation. Venetoclax releases Bim from Bcl-2 with increased Bim binding to Mcl-1. Artesunate, an antimalaria drug, induces Noxa to replace Bim from Mcl-1 and induces synergistic apoptosis with venetoclax accompanied with Mcl-1 reduction. Silencing Mcl-1 or adding venetoclax/artesunate diminishes the cytarabine resistance pathway p-Chk1. The triple combination exhibits S phase arrest with enhanced DNA damage, improves AML colony formation inhibition, and prolongs survival of two mice xenograft models compared to the venetoclax/cytarabine dual combination. Artesunate serves as a bridge for venetoclax and cytarabine combination by Noxa and Bim-mediated apoptosis and Mcl-1 reduction. We provide a new triple combination for AML treatment by targeting the Noxa/Mcl-1/Bim axis to reverse Mcl-1/p-Chk1 resistance of cytarabine therapy.
  26. Nat Commun. 2022 Apr 19. 13(1): 2048
      The heterogeneous nature of human CD34+ hematopoietic stem cells (HSCs) has hampered our understanding of the cellular and molecular trajectories that HSCs navigate during lineage commitment. Using various platforms including single cell RNA-sequencing and extensive xenotransplantation, we have uncovered an uncharacterized human CD34+ HSC population. These CD34+EPCR+(CD38/CD45RA)- (simply as EPCR+) HSCs have a high repopulating and self-renewal abilities, reaching a stem cell frequency of ~1 in 3 cells, the highest described to date. Their unique transcriptomic wiring in which many gene modules associated with differentiated cell lineages confers their multilineage lineage output both in vivo and in vitro. At the single cell level, EPCR+ HSCs are the most transcriptomically and functionally homogenous human HSC population defined to date and can also be easily identified in post-natal tissues. Therefore, this EPCR+ population not only offers a high human HSC resolution but also a well-structured human hematopoietic hierarchical organization at the most primitive level.
  27. Blood. 2022 Apr 18. pii: blood.2021013068. [Epub ahead of print]
      While Ras/mitogen-activated protein kinase (MAPK) signaling is activated in most human cancers, attempts to target this pathway using kinase active site inhibitors have not typically led to durable, clinical benefit. To address this shortcoming, we sought to test the feasibility of an alternative targeting strategy, focused on the ERK2 substrate binding domains, D and DBP. We found that disabling the ERK2-DBP domain in mice caused baseline erythrocytosis. Consequently, we investigated the role of the ERK2-D and -DBP domains in disease, using a JAK2-dependent model of polycythemia vera (PV). Importantly, inactivation of the ERK2-DBP domain promoted the progression of disease from PV to myelofibrosis (MF), suggesting that the ERK2-DBP domain normally opposes progression. ERK2-DBP inactivation also prevented oncogenic JAK2 kinase (JAK2V617F) from promoting oncogene-induced senescence (OIS) in vitro. The ERK2-DBP mutation attenuated JAK2-mediated OIS by preventing the physical interaction of ERK2 with the transcription factor, Egr1. Because inactivation of the ERK2-DBP created a functional ERK2 kinase limited to binding substrates through its D-domain, these data suggested that the D-domain substrates were responsible for promoting oncogene-induced progenitor growth and tumor progression, and that pharmacologic targeting of the ERK2-D domain might attenuate cancer cell growth. Indeed, pharmacologic agents targeting the ERK2-D domain were effective in attenuating the growth of JAK2-dependent myeloproliferative neoplasm cell lines. Taken together, these data indicate that the ERK-D and -DBP domains can play distinct roles in the progression of neoplasms and that the D-domain has the potential to be potent therapeutic target in Ras/MAPK dependent cancers.
  28. Cancer Cell. 2022 Apr 15. pii: S1535-6108(22)00157-X. [Epub ahead of print]
      Chimeric antigen receptor (CAR) T cell therapy is effective in lymphoid malignancies, but there has been limited data in myeloid cancers. Here, we start with a CD27-based CAR to target CD70 ("native") in acute myeloid leukemia (AML), and we find modest efficacy in vivo, consistent with prior reports. We then use orthogonal approaches to increase binding on both the tumor and CAR-T cell sides of the immune synapse: a pharmacologic approach (azacitidine) to increase antigen density of CD70 in myeloid tumors, and an engineering approach to stabilize binding of the CAR to CD70. To accomplish the latter, we design a panel of hinge-modified regions to mitigate cleavage of the extracellular portion of CD27. Our CD8 hinge and transmembrane-modified CD70 CAR-T cells are less prone to cleavage, have enhanced binding avidity, and increased expansion, leading to more potent in vivo activity. This enhanced CD70-targeted CAR is a promising candidate for further clinical development.
    Keywords:  acute myeloid leukemia; adoptive T cell therapy; cell engineering; cellular immunity; chimeric antigen receptors; combined modality therapy; hematologic neoplasms
  29. Leuk Lymphoma. 2022 Apr 22. 1-8
      The frailty index (FI) predicts clinical outcomes in oncology. However, in the acute myeloid leukemia (AML) setting, its predictive ability is poorly understood. We assessed whether the FI predicts complete remission (CR), intensive care unit (ICU) admission, and 1-year all-cause mortality in younger and older adults with AML receiving intensity chemotherapy. This was a secondary analysis of a prospective study. In total, 237 patients (n = 140 younger and n = 97 older adults) were classified as non-frail, prefrail, or frail. Frail younger adults were less likely to achieve CR compared with non-frail younger adults. Pre-frail and frail younger adults were more likely to be admitted to the ICU compared with their non-frail counterparts. The FI was not predictive of 1-year all-cause mortality. The FI predicts CR and ICU admission in younger but not older adults. Disease biology may be more important than frailty in predicting 1-year overall mortality in patients with AML undergoing chemotherapy.
    Keywords:  Frailty; acute myeloid leukemia; complete remission; intensive care unit admission; mortality
  30. Cell Metab. 2022 Apr 18. pii: S1550-4131(22)00127-9. [Epub ahead of print]
      Glycolysis, including both lactate fermentation and pyruvate oxidation, orchestrates CD8+ T cell differentiation. However, how mitochondrial pyruvate metabolism and uptake controlled by the mitochondrial pyruvate carrier (MPC) impact T cell function and fate remains elusive. We found that genetic deletion of MPC drives CD8+ T cell differentiation toward a memory phenotype. Metabolic flexibility induced by MPC inhibition facilitated acetyl-coenzyme-A production by glutamine and fatty acid oxidation that results in enhanced histone acetylation and chromatin accessibility on pro-memory genes. However, in the tumor microenvironment, MPC is essential for sustaining lactate oxidation to support CD8+ T cell antitumor function. We further revealed that chimeric antigen receptor (CAR) T cell manufacturing with an MPC inhibitor imprinted a memory phenotype and demonstrated that infusing MPC inhibitor-conditioned CAR T cells resulted in superior and long-lasting antitumor activity. Altogether, we uncover that mitochondrial pyruvate uptake instructs metabolic flexibility for guiding T cell differentiation and antitumor responses.
    Keywords:  T cell memory; chimeric antigen receptor T cell therapy; immunometabolism; mitochondrial pyruvate carrier; tumor-infiltrating lymphocyte metabolism
  31. Nat Commun. 2022 Apr 22. 13(1): 2206
      Targeting ferroptosis, a unique cell death modality triggered by unrestricted lipid peroxidation, in cancer therapy is hindered by our incomplete understanding of ferroptosis mechanisms under specific cancer genetic contexts. KEAP1 (kelch-like ECH associated protein 1) is frequently mutated or inactivated in lung cancers, and KEAP1 mutant lung cancers are refractory to most therapies, including radiotherapy. In this study, we identify ferroptosis suppressor protein 1 (FSP1, also known as AIFM2) as a transcriptional target of nuclear factor erythroid 2-related factor 2 (NRF2) and reveal that the ubiquinone (CoQ)-FSP1 axis mediates ferroptosis- and radiation- resistance in KEAP1 deficient lung cancer cells. We further show that pharmacological inhibition of the CoQ-FSP1 axis sensitizes KEAP1 deficient lung cancer cells or patient-derived xenograft tumors to radiation through inducing ferroptosis. Together, our study identifies CoQ-FSP1 as a key downstream effector of KEAP1-NRF2 pathway and as a potential therapeutic target for treating KEAP1 mutant lung cancers.
  32. RSC Chem Biol. 2022 Apr 06. 3(4): 456-467
      Epigenetic regulation is a dynamic and reversible process that controls gene expression. Abnormal function results in human diseases such as cancer, thus the enzymes that establish epigenetic marks, such as histone methyltransferases (HMTs), are potentially therapeutic targets. Noteworthily, HMTs form multiprotein complexes that in concert regulate gene expression. To probe epigenetic protein complexes regulation in cells, we developed a reliable chemical biology high-content imaging strategy to screen compound libraries simultaneously on multiple histone marks inside cells. By this approach, we identified that compound 4, a published CARM1 inhibitor, inhibits both histone mark H3R2me2a, regulated also by CARM1, and H3K79me2, regulated only by DOT1L, pointing out a crosstalk between CARM1 and DOT1L. Based on this interaction, we combined compound 4 and DOT1L inhibitor EPZ-5676 resulting in a stronger inhibition of cell proliferation and increase in apoptosis, indicating that our approach identifies possible effective synergistic drug combinations.
  33. Haematologica. 2022 Apr 21.
      Somatic mutations are recognized as an important prognostic factor in chronic myelomonocytic leukemia (CMML). However, limited data are available regarding their impact on outcomes after allogeneic hematopoietic cell transplantation (alloHCT). In this registry analysis conducted in collaboration with the Center for International Blood and Marrow Transplantation Registry (CIBMTR) database/sample repository, we identified 313 adult patients with CMML (median age: 64 years, range: 28-77) who underwent alloHCT during 2001-2017 and had an available biospecimen in the form of a peripheral blood sample obtained prior to the start of conditioning. In multivariate analysis, a CMML-specific prognostic scoring system (CPSS) score of intermediate-2 (HR=1.46, p=0.049) or high (HR=3.22, p=0.0004) correlated significantly with overall survival (OS). When the molecularly informed CPSS-Mol was applied, a high CPSS-Mol score (HR=2 p=0.0079) correlated significantly with OS. The most common somatic mutations were ASXL1 (62%), TET2 (35%), KRAS/NRAS (33% combined), and SRSF2 (31%). DNMT3A and TP53 mutations were associated with decreased OS (HR=1.70 [95%CI: 1.11-2.60], p=0.0147 and HR=2.72 [95%CI: 1.37-5.39], p=0.0042, respectively) while DNMT3A, JAK2, and TP53 mutations were associated with decreased disease-free survival (DFS) (HR=1.66 [95%CI: 1.11-2.49], p=0.0138, HR=1.79 [95%CI: 1.06- 3.03], p=0.0293, and HR=2.94 [95%CI: 1.50-5.79], p=0.0018 respectively). The only mutation associated with increased relapse was TP53 (HR=2.94, p=0.0201). Nonetheless, the impact specifically of TP53 mutations should be interpreted cautiously given its rarity in CMML. We calculated the goodness of fit measured by Harrell's C-index for both the CPSS and CPSS-Mol, which were very similar. In summary, via registry data we have provided the mutational landscape in patients with CMML who underwent alloHCT, and we demonstrated an association between CPSS-Mol and transplant outcomes although without major improvement in the risk prediction beyond the CPSS.
  34. Antioxidants (Basel). 2022 Mar 31. pii: 683. [Epub ahead of print]11(4):
      The cytosolic branched-chain aminotransferase (BCAT1) has received attention for its role in myeloid leukaemia development, where studies indicate metabolic adaptations due to BCAT1 up-regulation. BCAT1, like the mitochondria isoform (BCAT2), shares a conserved CXXC motif ~10 Å from the active site. This CXXC motif has been shown to act as a 'redox-switch' in the enzymatic regulation of the BCAT proteins, however the response to reactive oxygen species (ROS) differs between BCAT isoforms. Studies indicate that the BCAT1 CXXC motif is several orders of magnitude less sensitive to the effects of ROS compared with BCAT2. Moreover, estimation of the reduction mid-point potential of BCAT1, indicates that BCAT1 is more reductive in nature and may possess antioxidant properties. Therefore, the aim of this study was to further characterise the BCAT1 CXXC motif and evaluate its role in acute myeloid leukaemia. Our biochemical analyses show that purified wild-type (WT) BCAT1 protein could metabolise H2O2 in vitro, whereas CXXC motif mutant or WT BCAT2 could not, demonstrating for the first time a novel antioxidant role for the BCAT1 CXXC motif. Transformed U937 AML cells over-expressing WT BCAT1, showed lower levels of intracellular ROS compared with cells over-expressing the CXXC motif mutant (CXXS) or Vector Controls, indicating that the BCAT1 CXXC motif may buffer intracellular ROS, impacting on cell proliferation. U937 AML cells over-expressing WT BCAT1 displayed less cellular differentiation, as observed by a reduction of the myeloid markers; CD11b, CD14, CD68, and CD36. This finding suggests a role for the BCAT1 CXXC motif in cell development, which is an important pathological feature of myeloid leukaemia, a disease characterised by a block in myeloid differentiation. Furthermore, WT BCAT1 cells were more resistant to apoptosis compared with CXXS BCAT1 cells, an important observation given the role of ROS in apoptotic signalling and myeloid leukaemia development. Since CD36 has been shown to be Nrf2 regulated, we investigated the expression of the Nrf2 regulated gene, TrxRD1. Our data show that the expression of TrxRD1 was downregulated in transformed U937 AML cells overexpressing WT BCAT1, which taken with the reduction in CD36 implicates less Nrf2 activation. Therefore, this finding may implicate the BCAT1 CXXC motif in wider cellular redox-mediated processes. Altogether, this study provides the first evidence to suggest that the BCAT1 CXXC motif may contribute to the buffering of ROS levels inside AML cells, which may impact ROS-mediated processes in the development of myeloid leukaemia.
    Keywords:  AML; BCAT1; CXXC-motif; ROS; antioxidant; cysteine; leukaemia; myeloid
  35. Clin Cancer Res. 2022 Apr 18. pii: clincanres.4498.2021. [Epub ahead of print]
      On July 7, 2020, the Food and Drug Administration approved Inqovi (Otsuka Pharmaceutical Co.), an oral fixed dose combination tablet comprising 35 mg decitabine, a hypomethylating agent, and 100 mg cedazuridine, a cytidine deaminase inhibitor (abbreviated DEC-C) for treatment of adult patients with myelodysplastic syndromes (MDS). Evidence of effectiveness of DEC-C was established in Phase 3 ASTX727-02 (N=133) in adults with MDS. The study involved a 2-sequence crossover comparing DEC-C and intravenous (IV) decitabine 20 mg/m2 once daily for the first 5 days of each 28-day cycle in the first 2 cycles. From Cycle 3 onwards, patients received DEC-C. Five-day cumulative area under the curve (5-d AUC) of decitabine for DEC-C was similar to that of IV decitabine with geometric mean ratio 0.99 (90% confidence interval: 0.93, 1.06). Clinical benefit was supported by Study ASTX727-02 and the similarly designed Phase 2 Study ASTX727-01-B (n=80), with complete remission (CR) of 21% and 18% and median duration of CR 7.5 and 8.7 months, respectively. Adverse reactions were consistent with IV decitabine. Post-marketing assessments were issued to address the effect of cedazuridine on QT prolongation, food effect, moderate and severe hepatic impairment, and severe renal impairment on the pharmacokinetics and safety of DEC-C.
  36. Cell Death Discov. 2022 Apr 20. 8(1): 212
      Tyrosine kinase inhibitors (TKIs) such as imatinib (IM) are key drugs for treatment of chronic myeloid leukemia (CML). Development of drug resistance to TKIs due to BCR-ABL mutation, especially T315I mutation, poses a major challenge in the clinical treatment of CML. The purpose of this study was to test metabolic modulation as a potential strategy to overcome imatinib resistance based on the possible crosstalk between BCR-ABL signaling and metabolic changes in CML. 2-deoxy-d-glucose (2-DG) was used to modulate the glucose metabolism in CML cells sensitive to IM (KBM5 cell line) and resistant to imatinib with BCR-ABL T315I mutation (KBM5-T315I cell line). Seahorse XFe24 extracellular flux analyzer to quantify oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) was used to measure cellular energy metabolism. Cell proliferation was analyzed by CCK-8 assay and MTS assay. Annexin V/PI staining was used to evaluate cell apoptosis. Autophagy-related proteins and enzyme/proteins were detected by Western blotting. Cellular ATP concentration was detected using an ATP-based Cell Titer Kit. The combined action of 2-DG and IM was evaluated by calculating the drug combination index. Our results found that inhibition of glucose metabolism by 2-DG significantly impaired the viability of CML cells and co-treatment with 2-DG and imatinib induced a synergistic inhibition of KBM5 and KBM5-T315I cells. 2-DG induced cell death by autophagy, not by apoptosis, as evidenced by increased expression of Beclin1 and LC3AII and lack of annexin V/PI-positive cells. At the biochemical level, 2-DG inhibited glycolysis and mitochondrial oxygen consumption manifested by a significant decrease in ECAR and OCR, and a depletion of ATP. The severe metabolic stress induced by 2-DG in CML cells led to autophagic cell death. Our results suggested a metabolic vulnerability of CML cells that could be targeted by a combination of 2-DG and imatinib as an alternative treatment for imatinib-resistant CML.