bims-tremyl Biomed News
on Therapy resistance biology in myeloid leukemia
Issue of 2020‒08‒09
23 papers selected by
Paolo Gallipoli
Barts Cancer Institute, Queen Mary University of London


  1. Leukemia. 2020 Aug 06.
    Au YZ, Gu M, De Braekeleer E, Gozdecka M, Aspris D, Tarumoto Y, Cooper J, Yu J, Ong SH, Chen X, Tzelepis K, Huntly BJP, Vassiliou G, Yusa K.
      Histone acetyltransferases (HATs) catalyze the transfer of an acetyl group from acetyl-CoA to lysine residues of histones and play a central role in transcriptional regulation in diverse biological processes. Dysregulation of HAT activity can lead to human diseases including developmental disorders and cancer. Through genome-wide CRISPR-Cas9 screens, we identified several HATs of the MYST family as fitness genes for acute myeloid leukemia (AML). Here we investigate the essentiality of lysine acetyltransferase KAT7 in AMLs driven by the MLL-X gene fusions. We found that KAT7 loss leads to a rapid and complete loss of both H3K14ac and H4K12ac marks, in association with reduced proliferation, increased apoptosis, and differentiation of AML cells. Acetyltransferase activity of KAT7 is essential for the proliferation of these cells. Mechanistically, our data propose that acetylated histones provide a platform for the recruitment of MLL-fusion-associated adaptor proteins such as BRD4 and AF4 to gene promoters. Upon KAT7 loss, these factors together with RNA polymerase II rapidly dissociate from several MLL-fusion target genes that are essential for AML cell proliferation, including MEIS1, PBX3, and SENP6. Our findings reveal that KAT7 is a plausible therapeutic target for this poor prognosis AML subtype.
    DOI:  https://doi.org/10.1038/s41375-020-1001-z
  2. Cancers (Basel). 2020 Aug 04. pii: E2163. [Epub ahead of print]12(8):
    Hsiao PC, Chang JH, Lee WJ, Ku CC, Tsai MY, Yang SF, Chien MH.
      Curcumin (CUR) has a range of therapeutic benefits against cancers, but its poor solubility and low bioavailability limit its clinical use. Demethoxycurcumin (DMC) and diphenyl difluoroketone (EF-24) are natural and synthetic curcumin analogues, respectively, with better solubilities and higher anti-carcinogenic activities in various solid tumors than CUR. However, the efficacy of these analogues against non-solid tumors, particularly in acute myeloid leukemia (AML), has not been fully investigated. Herein, we observed that both DMC and EF-24 significantly decrease the proportion of viable AML cells including HL-60, U937, and MV4-11, harboring different NRAS and Fms-like tyrosine kinase 3 (FLT3) statuses, and that EF-24 has a lower half maximal inhibitory concentration (IC50) than DMC. We found that EF-24 treatment induces several features of apoptosis, including an increase in the sub-G1 population, phosphatidylserine (PS) externalization, and significant activation of extrinsic proapoptotic signaling such as caspase-8 and -3 activation. Mechanistically, p38 mitogen-activated protein kinase (MAPK) activation is critical for EF-24-triggered apoptosis via activating protein phosphatase 2A (PP2A) to attenuate extracellular-regulated protein kinase (ERK) activities in HL-60 AML cells. In the clinic, patients with AML expressing high level of PP2A have the most favorable prognoses compared to various solid tumors. Taken together, our results indicate that EF-24 is a potential therapeutic agent for treating AML, especially for cancer types that lose the function of the PP2A tumor suppressor.
    Keywords:  EF-24; acute myeloid leukemia; apoptosis; extracellular-regulated protein kinase; p38 mitogen-activated protein kinase; protein phosphatase 2 a
    DOI:  https://doi.org/10.3390/cancers12082163
  3. Nat Med. 2020 Aug 03.
    Bernard E, Nannya Y, Hasserjian RP, Devlin SM, Tuechler H, Medina-Martinez JS, Yoshizato T, Shiozawa Y, Saiki R, Malcovati L, Levine MF, Arango JE, Zhou Y, Solé F, Cargo CA, Haase D, Creignou M, Germing U, Zhang Y, Gundem G, Sarian A, van de Loosdrecht AA, Jädersten M, Tobiasson M, Kosmider O, Follo MY, Thol F, Pinheiro RF, Santini V, Kotsianidis I, Boultwood J, Santos FPS, Schanz J, Kasahara S, Ishikawa T, Tsurumi H, Takaori-Kondo A, Kiguchi T, Polprasert C, Bennett JM, Klimek VM, Savona MR, Belickova M, Ganster C, Palomo L, Sanz G, Ades L, Della Porta MG, Smith AG, Werner Y, Patel M, Viale A, Vanness K, Neuberg DS, Stevenson KE, Menghrajani K, Bolton KL, Fenaux P, Pellagatti A, Platzbecker U, Heuser M, Valent P, Chiba S, Miyazaki Y, Finelli C, Voso MT, Shih LY, Fontenay M, Jansen JH, Cervera J, Atsuta Y, Gattermann N, Ebert BL, Bejar R, Greenberg PL, Cazzola M, Hellström-Lindberg E, Ogawa S, Papaemmanuil E.
      Tumor protein p53 (TP53) is the most frequently mutated gene in cancer1,2. In patients with myelodysplastic syndromes (MDS), TP53 mutations are associated with high-risk disease3,4, rapid transformation to acute myeloid leukemia (AML)5, resistance to conventional therapies6-8 and dismal outcomes9. Consistent with the tumor-suppressive role of TP53, patients harbor both mono- and biallelic mutations10. However, the biological and clinical implications of TP53 allelic state have not been fully investigated in MDS or any other cancer type. We analyzed 3,324 patients with MDS for TP53 mutations and allelic imbalances and delineated two subsets of patients with distinct phenotypes and outcomes. One-third of TP53-mutated patients had monoallelic mutations whereas two-thirds had multiple hits (multi-hit) consistent with biallelic targeting. Established associations with complex karyotype, few co-occurring mutations, high-risk presentation and poor outcomes were specific to multi-hit patients only. TP53 multi-hit state predicted risk of death and leukemic transformation independently of the Revised International Prognostic Scoring System (IPSS-R)11. Surprisingly, monoallelic patients did not differ from TP53 wild-type patients in outcomes and response to therapy. This study shows that consideration of TP53 allelic state is critical for diagnostic and prognostic precision in MDS as well as in future correlative studies of treatment response.
    DOI:  https://doi.org/10.1038/s41591-020-1008-z
  4. Cancer Chemother Pharmacol. 2020 Aug 03.
    Elmeliegy M, Den Haese J, Talati C, Wetzler M, Jusko WJ.
      BACKGROUND: AML patients with FLT3/ITD mutations have poor response to cytarabine-based chemotherapy. FLT3 inhibitors (FLT3i) may resensitize cells to cytarabine (CYT). Improving treatment outcome of this combination may benefit from a mechanistic extrapolation approach from in vitro data.METHODS: The effects of CYT and several FLT3i on cell proliferation and cell cycle kinetics were examined in AML cell lines. The effect of FLT3i (quizartinib, midostaurin, sorafenib) on cell proliferation and cell cycle kinetics was assessed in AML cell lines with differing FLT3 status; HEL (negligible expression of wild-type FLT3), EOL1 (wild-type FLT3), MV4-11 (FLT3-ITD resulting in constitutively active isoform). Semi-mechanistic cell cycle models for CYT and FLT3i were developed. Clinical CYT and quizartinib pharmacokinetic dosage regimens were modeled. Survival of AML patients was described via a hazard model. Simulations exploring different CYT/quizartinib regimens were conducted with the goal of improving treatment outcome.
    RESULTS: FLT3 status was associated with sensitivity to CYT (HEL cells most sensitive > EOL1 > MV4-11 cells). This order of sensitivity is reversed for FLT3i. Cytarabine induced apoptosis in the S-phase while all FLT3i induced apoptosis and cell cycle arrest at G1 phase. Simulations of candidate clinical regimens predict better cell kill upon adding quizartinib simultaneously with or immediately after CYT exposure. Overall survival was predicted to be significantly better with quizartinib 200 mg administered every 48 h vs every 24 h in patients with FLT3 aberrations.
    CONCLUSION: Simultaneous administration of quizartinib and CYT every other day is a promising combination regimen for AML patients with FLT3 mutations.
    Keywords:  AML; Cell cycle; Combination; Cytotoxicity; Pharmacodynamic modeling
    DOI:  https://doi.org/10.1007/s00280-020-04114-z
  5. BMC Cancer. 2020 Aug 05. 20(1): 732
    Wang Y, Wang H, Wang W, Liu W, Liu N, Liu S, Lu Y.
      BACKGROUND: Risk stratification and prognosis prediction of acute myeloid leukemia (AML) are largely dependent on pre-treatment information. However, post-treatment data also provides much useful information. In this retrospective study, we explored whether the level of blood count recovery before and after the first minimal residual disease (MRD) negative complete remission (CR) is relevant to clinical outcomes of AML patients.METHODS: For each included patient, peripheral platelet counts were measured on the day before initial treatment (PLTpre), whereas platelet peak values (PLTpeak) were recorded after marrow recovery following the chemotherapy course inducing the first MRD-negative CR. The difference (DPLT) between these two values (DPLT = PLTpeak-PLTpre) was calculated. X-tile software was utilized to establish the optimal cut-point for DPLT, which was expected to distinguish CR patients with different clinical outcomes. A cross validation analysis was conducted to confirm the robustness of the established cut-point. The results were further tested by a Cox multivariate analysis.
    RESULTS: The optimal cut-point of DPLT was determined as 212 × 109/L. Patients in high DPLT group were observed to have a significantly better PFS (p = 0.016) and a better OS (without statistical significance, p = 0.106). Cox multivariate analysis showed that higher DPLT was associated with longer PFS (HR = 2.894, 95% CI: 1.320-6.345, p = 0.008) and longer OS (HR = 3.077, 95% CI: 1.130-8.376, p = 0.028).
    CONCLUSION: Platelet recovery degree before and after achieving MRD-negative CR (DPLT) is a potential predictor of clinical outcomes in CR patients. Higher DPLT value is associated with longer PFS and OS. Our findings may help to develop simple methods for AML prognosis evaluation.
    Keywords:  Acute myeloid leukemia (AML); Complete remission (CR); Overall survival (OS); Platelet recovery degree; Progression free survival (PFS)
    DOI:  https://doi.org/10.1186/s12885-020-07222-4
  6. Cell Metab. 2020 Jul 30. pii: S1550-4131(20)30367-3. [Epub ahead of print]
    van Gastel N, Spinelli JB, Sharda A, Schajnovitz A, Baryawno N, Rhee C, Oki T, Grace E, Soled HJ, Milosevic J, Sykes DB, Hsu PP, Vander Heiden MG, Vidoudez C, Trauger SA, Haigis MC, Scadden DT.
      Cancer relapse begins when malignant cells pass through the extreme metabolic bottleneck of stress from chemotherapy and the byproducts of the massive cell death in the surrounding region. In acute myeloid leukemia, complete remissions are common, but few are cured. We tracked leukemia cells in vivo, defined the moment of maximal response following chemotherapy, captured persisting cells, and conducted unbiased metabolomics, revealing a metabolite profile distinct from the pre-chemo growth or post-chemo relapse phase. Persisting cells used glutamine in a distinctive manner, preferentially fueling pyrimidine and glutathione generation, but not the mitochondrial tricarboxylic acid cycle. Notably, malignant cell pyrimidine synthesis also required aspartate provided by specific bone marrow stromal cells. Blunting glutamine metabolism or pyrimidine synthesis selected against residual leukemia-initiating cells and improved survival in leukemia mouse models and patient-derived xenografts. We propose that timed cell-intrinsic or niche-focused metabolic disruption can exploit a transient vulnerability and induce metabolic collapse in cancer cells to overcome chemoresistance.
    Keywords:  acute myeloid leukemia; aspartate; bone marrow niche; cell metabolism; chemotherapy; glutamine; mouse models; patient-derived xenografts; pyrimidine synthesis; tumor microenvironment
    DOI:  https://doi.org/10.1016/j.cmet.2020.07.009
  7. Onco Targets Ther. 2020 ;13 6897-6905
    Luo H, Sun R, Zheng Y, Huang J, Wang F, Long D, Wu Y.
      Purpose: Acute myeloid leukemia (AML) is associated with a poor overall prognosis. PIM family genes, including PIM1, PIM2, and PIM3, are proto-oncogenes that are aberrantly overexpressed in different types of human cancers. In this study, we aimed to explore and clarify the function of PIM3 in AML.Patients and Methods: The expression of the three PIM genes in AML was detected using the Gene Expression Omnibus. The expression of PIM3 and PIM3 in patient samples and AML cell lines was measured using quantitative real-time polymerase chain reaction or Western blot analyses. The cellular behaviors of PIM3-overexpressing AML cell lines were detected using a CCK-8 assay, flow cytometry, Western blotting, immunofluorescence staining, and a cell migration assay. The interactions between PIM3 and phosphorylated CXCR4 (pCXCR4) were explored via immunoprecipitation.
    Results: Higher PIM3 expression was detected in primary AML cells than in healthy donor cells. Second, PIM3 overexpression promoted AML cell proliferation and protected against spontaneous apoptosis by phosphorylating BAD (pBAD) at Ser112. Furthermore, PIM3 overexpression might promote the migration of AML cells via CXCR4. PIM3-overexpressing AML cell lines exhibited increased CXCR4 phosphorylation at Ser339, and pCXCR4 interacted with PIM3.
    Conclusion: Our findings suggest that PIM3 regulates the proliferation, survival, and chemotaxis of AML cell lines. Moreover, pCXCR4 might mediate the regulation of PIM3-induced chemotaxis. Therefore, the inhibition of PIM3 expression may be a promising therapeutic target in AML.
    Keywords:  PIM1; PIM2; PIM3; pBAD; pCXCR4
    DOI:  https://doi.org/10.2147/OTT.S245578
  8. Cancers (Basel). 2020 Aug 05. pii: E2171. [Epub ahead of print]12(8):
    Valhondo I, Hassouneh F, Lopez-Sejas N, Pera A, Sanchez-Correa B, Guerrero B, Bergua JM, Arcos MJ, Bañas H, Casas-Avilés I, Sanchez-Garcia J, Serrano J, Martin C, Duran E, Alonso C, Solana R, Tarazona R.
      Background: Acute myeloid leukemia (AML) remains a major clinical challenge due to poor overall survival, which is even more dramatic in elderly patients. TIGIT, an inhibitory receptor that interacts with CD155 and CD112 molecules, is considered as a checkpoint in T and NK cell activation. This receptor shares ligands with the co-stimulatory receptor DNAM-1 and with TACTILE. The aim of this work was to analyze the expression of DNAM-1, TIGIT and TACTILE in NK cells and T cell subsets in AML patients. Methods: We have studied 36 patients at the time of diagnosis of AML and 20 healthy volunteers. The expression of DNAM-1, TIGIT and TACTILE in NK cells and T cells, according to the expression of CD3 and CD56, was performed by flow cytometry. Results: NK cells, CD56- T cells and CD56+ T (NKT-like) cells from AML patients presented a reduced expression of DNAM-1 compared with healthy volunteers. An increased expression of TIGIT was observed in mainstream CD56- T cells. No differences were observed in the expression of TACTILE. Simplified presentation of incredibly complex evaluations (SPICE) analysis of the co-expression of DNAM-1, TIGIT and TACTILE showed an increase in NK and T cells lacking DNAM-1 and co-expressing TIGIT and TACTILE. Low percentages of DNAM-1-TIGIT+TACTILE+ NK cells and DNAM-1- TIGIT+TACTILE+ CD56- T cells were associated with a better survival of AML patients. Conclusions: The expression of DNAM-1 is reduced in NK cells and in CD4+ and CD8+ T cells from AML patients compared with those from healthy volunteers. An increased percentage of NK and T cells lacking DNAM-1 and co-expressing TIGIT and TACTILE is associated with patient survival, supporting the role of TIGIT as a novel candidate for checkpoint blockade.
    Keywords:  DNAM-1; NK cells; NKT-like cells; T cells; TACTILE; TIGIT; acute myeloid leukemia
    DOI:  https://doi.org/10.3390/cancers12082171
  9. Blood Adv. 2020 Aug 11. 4(15): 3528-3549
    Sekeres MA, Guyatt G, Abel G, Alibhai S, Altman JK, Buckstein R, Choe H, Desai P, Erba H, Hourigan CS, LeBlanc TW, Litzow M, MacEachern J, Michaelis LC, Mukherjee S, O'Dwyer K, Rosko A, Stone R, Agarwal A, Colunga-Lozano LE, Chang Y, Hao Q, Brignardello-Petersen R.
      BACKGROUND: Older adults with acute myeloid leukemia (AML) represent a vulnerable population in whom disease-based and clinical risk factors, patient goals, prognosis, and practitioner- and patient-perceived treatment risks and benefits influence treatment recommendations.OBJECTIVE: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about management of AML in older adults.
    METHODS: ASH formed a multidisciplinary guideline panel that included specialists in myeloid leukemia, geriatric oncology, patient-reported outcomes and decision-making, frailty, epidemiology, and methodology, as well as patients. The McMaster Grading of Recommendations Assessment, Development and Evaluation (GRADE) Centre supported the guideline-development process, including performing systematic evidence reviews (up to 24 May 2019). The panel prioritized clinical questions and outcomes according to their importance to patients, as judged by the panel. The panel used the GRADE approach, including GRADE's Evidence-to-Decision frameworks, to assess evidence and make recommendations, which were subject to public comment.
    RESULTS: The panel agreed on 6 critical questions in managing older adults with AML, mirroring real-time practitioner-patient conversations: the decision to pursue antileukemic treatment vs best supportive management, the intensity of therapy, the role and duration of postremission therapy, combination vs monotherapy for induction and beyond, duration of less-intensive therapy, and the role of transfusion support for patients no longer receiving antileukemic therapy.
    CONCLUSIONS: Treatment is recommended over best supportive management. More-intensive therapy is recommended over less-intensive therapy when deemed tolerable. However, these recommendations are guided by the principle that throughout a patient's disease course, optimal care involves ongoing discussions between clinicians and patients, continuously addressing goals of care and the relative risk-benefit balance of treatment.
    DOI:  https://doi.org/10.1182/bloodadvances.2020001920
  10. Stem Cells Transl Med. 2020 Aug 05.
    Mirali S, Schimmer AD.
      The biological function of most mitochondrial proteases has not been well characterized. Moreover, most of the available information on the normal function of these proteases has been derived from studies in model organisms. Recently, the mitochondrial proteases caseinolytic protease P (CLPP) and neurolysin (NLN) have been identified as therapeutic targets in acute myeloid leukemia (AML). Both proteases are overexpressed in approximately 40% of AML patients. Mechanistically, CLPP and NLN maintain the integrity of the mitochondrial respiratory chain: CLPP cleaves defective respiratory chain proteins, while NLN promotes the formation of respiratory chain supercomplexes. In this review, we highlight the functional consequences of inhibiting and activating mitochondrial proteases and discuss their potential as therapeutic targets in AML.
    DOI:  https://doi.org/10.1002/sctm.20-0142
  11. Front Cell Dev Biol. 2020 ;8 607
    Villatoro A, Konieczny J, Cuminetti V, Arranz L.
      Acute myeloid leukemia (AML) is a heterogeneous, complex, and deadly disease, whose treatment has hardly evolved for decades and grounds on the use of intensive chemotherapy regimens. Chemotherapy helps reduce AML bulk, but promotes relapse in the long-run by selection of chemoresistant leukemia stem cells (LSC). These may diversify and result in progression to more aggressive forms of AML. In vivo models suggest that the bone marrow stem cell niche helps LSC stay dormant and protected from chemotherapy. Here, we summarize relevant changes in stem cell niche homing and adhesion of AML LSC vs. healthy hematopoietic stem cells, and provide an overview of clinical trials aiming at targeting these processes for AML treatment and future directions within this field. Promising results with various non-mutation-targeted novel therapies directed to LSC eradication via interference with their anchoring to the stem cell niche have encouraged on-going or future advanced phase III clinical trials. In the coming years, we may see a shift in the focus of AML treatment to LSC-directed therapies if the prospect of improved cure rates holds true. In the future, AML treatment should lean toward personalized therapies using combinations of these compounds plus mutation-targeted agents and/or targeted delivery of chemotherapy, aiming at LSC eradication with reduced side effects.
    Keywords:  acute myeloid leukemia; adhesion; clinical trials; hematopoietic stem cell; hematopoietic stem cell niche; homing; leukemia stem cell; mobilization
    DOI:  https://doi.org/10.3389/fcell.2020.00607
  12. PLoS One. 2020 ;15(8): e0235503
    Yoo KH, Cho J, Han B, Kim SH, Shin DY, Hong J, Kim H, Kim HJ, Zang DY, Yoon SS, Jin JY, Lee JH, Hong DS, Park SK.
      PURPOSE: We evaluated the outcomes of decitabine as first-line treatment in older patients with acute myeloid leukemia (AML) and investigated the predictors, including a baseline mini nutritional assessment short form (MNA-SF) score, of response and survival.PATIENTS AND METHODS: Between 2010 and 2018, 96 AML patients aged 65 and above who received decitabine treatment at 6 centers in Korea were retrospectively evaluated. Response rates, hematologic improvements (HI), progression-free survival (PFS), and overall survival (OS) were analyzed.
    RESULTS: The median age at diagnosis was 73.9 years, and the median number of decitabine treatments administered to the patients was 4 (range, 1-29). Of 85 patients, 15 patients (17.6%) achieved complete remission (CR) or CR with incomplete blood count recovery. Twelve patients (14.1%) showed partial remission (PR), and 18 (21.2%) demonstrated HI without an objective response. The median PFS and OS were 7.0 (95% confidence interval [CI], 4.9-9.0) and 10.6 (95% CI, 7.7-13.5%) months, respectively. In multivariate analyses, MNA-SF score ≥ 8 and the absence of peripheral blood (PB) blasts were significant predictors for improved PFS and OS.
    CONCLUSIONS: For older patients with newly diagnosed AML, a high MNA-SF score and the absence of PB blasts were independently associated with improved survival.
    DOI:  https://doi.org/10.1371/journal.pone.0235503
  13. Leuk Lymphoma. 2020 Aug 05. 1-7
    Shaikh AF, Kakirde C, Dhamne C, Bhanshe P, Joshi S, Chaudhary S, Chatterjee G, Tembhare P, Prasad M, Roy Moulik N, Gokarn A, Bonda A, Nayak L, Punatkar S, Jain H, Bagal B, Shetty D, Sengar M, Narula G, Khattry N, Banavali S, Gujral S, P G S, Patkar N.
      Panel based next generation sequencing was performed on a discovery cohort of AML with RUNX1-RUNX1T1. Supervised machine learning identified NRAS mutation and absence of mutations in ASXL2, RAD21, KIT and FLT3 genes as well as a low mutation to be associated with favorable outcome. Based on this data patients were classified into favorable and poor genetic risk classes. Patients classified as poor genetic risk had a significantly lower overall survival (OS) and relapse free survival (RFS). We could validate these findings independently on a validation cohort (n = 61). Patients in the poor genetic risk group were more likely to harbor measurable residual disease. Poor genetic risk emerged as an independent risk factor predictive of inferior outcome. Using an unbiased computational approach based we provide evidence for gene panel-based testing in AML with RUNX1-RUNX1T1 and a framework for integration of genomic markers toward clinical decision making in this heterogeneous disease entity.
    Keywords:  Acute myeloid leukemia (AML) with RUNX1-RUNX1T1; gene mutations in AML with RUNX1-RUNX1T1; gene mutations in AML with t(8;21); genomic risk stratification; machine learning
    DOI:  https://doi.org/10.1080/10428194.2020.1798951
  14. Blood Adv. 2020 Aug 11. 4(15): 3626-3638
    Garcia-Cuellar MP, Lawlor J, Böttcher M, Mougiakakos D, Metzler M, Slany RK.
      Mixed-lineage leukemia (MLL) fusions are transcriptional activators that induce leukemia, with a dismal prognosis that mandates further elucidation of their transformation mechanism. In this study, knockdown of the direct MLL-ENL target gene polypyrimidine tract binding protein-1 (PTBP1) was rate limiting for cell proliferation and caused a metabolic phenotype associated with reduced glucose consumption and lactate production. This effect was accompanied by a reduction of splice isoform-2 of pyruvate kinase M (PKM2). Because PKM2 restricts glycolytic outflow to provide anabolic intermediates, we tested the consequences of glucose, energy, and Ser/Gly starvation for cell physiology. Administration of deoxyglucose, energetic decoupling with rotenone, and inhibition of Ser biosynthesis by CBR5884 had a significantly stronger influence on self-renewal and survival of transformed cells than on normal controls. In particular, inhibition of Ser synthesis, which branches off glycolysis caused accumulation of reactive oxygen species, DNA damage, and apoptosis, predominantly in leukemic cells. Depletion of exogenous Ser/Gly affected proliferation and self-renewal of murine and human leukemia samples, even though they are classified as nonessential amino acids. Response to Ser/Gly starvation correlated with glucose transport, but did not involve activation of the AMPK energy homeostasis system. Finally, survival times in transplantation experiments were significantly extended by feeding recipients a Ser/Gly-free diet. These results suggest selective starvation as an option for supportive leukemia treatment.
    DOI:  https://doi.org/10.1182/bloodadvances.2020001710
  15. Leukemia. 2020 Aug 04.
    Hershberger CE, Moyer DC, Adema V, Kerr CM, Walter W, Hutter S, Meggendorfer M, Baer C, Kern W, Nadarajah N, Twardziok S, Sekeres MA, Haferlach C, Haferlach T, Maciejewski JP, Padgett RA.
      Myeloid neoplasms are characterized by frequent mutations in at least seven components of the spliceosome that have distinct roles in the process of pre-mRNA splicing. Hotspot mutations in SF3B1, SRSF2, U2AF1 and loss of function mutations in ZRSR2 have revealed widely different aberrant splicing signatures with little overlap. However, previous studies lacked the power necessary to identify commonly mis-spliced transcripts in heterogeneous patient cohorts. By performing RNA-Seq on bone marrow samples from 1258 myeloid neoplasm patients and 63 healthy bone marrow donors, we identified transcripts frequently mis-spliced by mutated splicing factors (SF), rare SF mutations with common alternative splicing (AS) signatures, and SF-dependent neojunctions. We characterized 17,300 dysregulated AS events using a pipeline designed to predict the impact of mis-splicing on protein function. Meta-splicing analysis revealed a pattern of reduced levels of retained introns among disease samples that was exacerbated in patients with splicing factor mutations. These introns share characteristics with "detained introns," a class of introns that have been shown to promote differentiation by detaining pro-proliferative transcripts in the nucleus. In this study, we have functionally characterized 17,300 targets of mis-splicing by the SF mutations, identifying a common pathway by which AS may promote maintenance of a proliferative state.
    DOI:  https://doi.org/10.1038/s41375-020-1002-y
  16. Expert Opin Investig Drugs. 2020 Aug 04.
    Saxena K, Konopleva M.
      INTRODUCTION: Acute myeloid leukemia (AML) is an aggressive malignancy of clonal myeloid precursor cells. Curative therapy has classically involved the use of intensive induction chemotherapy followed by consolidation with additional chemotherapy or allogeneic hematopoietic stem cell transplant. For many patients, such an approach is prohibitive because of high treatment-related toxicities. Advancements in the molecular understanding of AML have led to the introduction of new targeted therapies that are changing the treatment landscape for AML.AREAS COVERED: We review emerging small molecule inhibitors that have shown preclinical efficacy for the treatment of AML. The compounds discussed affect apoptosis, p53-mediated interactions, transcriptional regulation, and cellular metabolism. We performed a literature search of PubMed and primarily included relevant sources published from 2000 to the present, though earlier sources are also referenced.
    EXPERT OPINION: Most clinical trials for AML currently employ novel targeted therapies that demonstrate promising activity in preclinical models. We anticipate that new small molecule inhibitors will continue to enter the clinical realm and alter the treatment paradigm for AML. In a field where clinical advancement was comparatively slow for many years, it appears that we are now starting to see the rapid growth borne out of the deepening molecular understanding of AML.
    DOI:  https://doi.org/10.1080/13543784.2020.1804856
  17. Cancers (Basel). 2020 Aug 05. pii: E2187. [Epub ahead of print]12(8):
    Meazza R, Falco M, Loiacono F, Canevali P, Della Chiesa M, Bertaina A, Pagliara D, Merli P, Indio V, Galaverna F, Algeri M, Moretta F, Colomar-Carando N, Muccio L, Sivori S, Pession A, Mingari MC, Moretta L, Moretta A, Locatelli F, Pende D.
      NK cells can exert remarkable graft-versus-leukemia (GvL) effect in HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT). Here, we dissected the NK-cell repertoire of 80 pediatric acute leukemia patients previously reported to have an excellent clinical outcome after αβT/B-depleted haplo-HSCT. This graft manipulation strategy allows the co-infusion of mature immune cells, mainly NK and γδT cells, and hematopoietic stem cells (HSCs). To promote NK-cell based antileukemia activity, 36/80 patients were transplanted with an NK alloreactive donor, defined according to the KIR/KIR-Ligand mismatch in the graft-versus-host direction. The analysis of the reconstituted NK-cell repertoire in these patients showed relatively high proportions of mature and functional KIR+NKG2A-CD57+ NK cells, including the alloreactive NK cell subset, one month after HSCT. Thus, the NK cells adoptively transfused with the graft persist as a mature source of effector cells while new NK cells differentiate from the donor HSCs. Notably, the alloreactive NK cell subset was endowed with the highest anti-leukemia activity and its size in the reconstituted repertoire could be influenced by human cytomegalovirus (HCMV) reactivation. While the phenotypic pattern of donor NK cells did not impact on post-transplant HCMV reactivation, in the recipients, HCMV infection/reactivation fostered a more differentiated NK-cell phenotype. In this cohort, no significant correlation between differentiated NK cells and relapse-free survival was observed.
    Keywords:  NK alloreactivity; NK cells; haploidentical hematopoietic stem cell transplantation (HSCT); human cytomegalovirus (HCMV); killer Ig-like receptors (KIR); pediatric acute leukemia
    DOI:  https://doi.org/10.3390/cancers12082187
  18. Leuk Lymphoma. 2020 Aug 05. 1-8
    Major CK, Kantarjian H, Sasaki K, Borthakur G, Kadia T, Pemmaraju N, DiNardo C, Short NJ, Daver N, Jabbour E, Champlin R, Garcia-Manero G, Konopleva M, Andreeff M, Kornblau S, Wierda W, Pierce S, Ravandi F, Cortes J.
      Acute myeloid leukemia (AML) carries poor survival and high recurrence rate. We conducted a retrospective analysis of AML patients (N = 453) treated with chemotherapy only or chemotherapy + hematopoietic cell transplant (HCT) who maintained their first complete remission (CR) for ≥3 years. Prior comorbidities, new comorbidities, secondary malignancies, late relapse, and causes of death (COD) were documented. New comorbidities for chemotherapy only patients (n = 304) included renal disease (10%), and osteopenia/osteoporosis (38%) for HCT patients (n = 149). Incidence of hypertension was similar in the chemotherapy only cohort and chemotherapy + HCT cohort (14% vs 17%). Secondary malignancies occurred in 13%, commonly skin, prostate and breast cancers. Common COD included: secondary malignancy (4%), HCT complications (3%), and late relapses (5%). Overall, 12% had a late relapse. Median overall survival for chemotherapy only and HCT was 10.7 and 12.7 years, respectively. Long-term AML survivors need routine monitoring for comorbidities, secondary malignancies, and late relapses.
    Keywords:  Acute myeloid leukemia; comorbidities; remission; survivorship
    DOI:  https://doi.org/10.1080/10428194.2020.1802450
  19. Cancer Biomark. 2020 Jul 24.
    Zhao Y, Zhang T, Zhao Y, Zhou J.
      BACKGROUND: The runt-related transcription factor family (RUNXs) including RUNX1, RUNX2, and RUNX3 are key transcriptional regulators in normal hematopoiesis. RUNXs dysregulations caused by aberrant expression or mutation are frequently seen in various human cancers especially in acute myeloid leukemia (AML).OBJECTIVE: We systemically analyzed the expression of RUNXs and their relationship with clinic-pathological features and prognosis in AML patients.
    METHODS: Expression of RUNXs was analyzed between AML patients and normal controls from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) projects. Correlations between RUNXs expression and clinical features together with survival were further analyzed.
    RESULTS: All RUNXs expression in AML patients was significantly increased as compared with controls. RUNXs expression was found to be significantly associated with genetic abnormalities such as RUNX1 mutation, t(8;21) and inv(16)/t(16;16). By Kaplan-Meier analysis, only RUNX3 overexpression was associated with shorter overall survival (OS) and disease-free survival (DFS) among non-M3 AML patients. Notably, in high RUNX3 expression groups, patients received hematopoietic stem cell transplantation (HSCT) had markedly better OS and DFS than patients without HSCT among both all AML and non-M3 AML. In low RUNX3 expression groups, there were no significant differences in OS and DFS between HSCT and non-HSCT groups among both all AML and non-M3 AML. In addition, a total of 835 differentially expressed genes and 69 differentially expressed microRNAs were identified to be correlated with RUNX3 expression in AML.
    CONCLUSION: RUNXs overexpression was a frequent event in AML, and was closely associated with diverse genetic alterations. Moreover, RUNX3 expression may be associated with clinical outcome, and helpful for guiding treatment choice between HSCT and chemotherapy in AML.
    Keywords:  RUNX; acute myeloid leukemia; biomarker; expression; prognosis
    DOI:  https://doi.org/10.3233/CBM-200016
  20. Clin Lymphoma Myeloma Leuk. 2020 Jul 06. pii: S2152-2650(20)30334-7. [Epub ahead of print]
    Dhakal P, Shostrom V, Al-Kadhimi ZS, Maness LJ, Gundabolu K, Bhatt VR.
      INTRODUCTION: Older adults with acute myeloid leukemia (AML) often have significant comorbidities. We hypothesized that greater comorbidity burden predicts worse 1-month mortality and overall survival (OS) in patients ≥60 years with AML.MATERIALS AND METHODS: We included 50,668 patients ≥60 years diagnosed between 2004 and 2014 from the National Cancer Database; patients were divided into 3 groups with Charlson comorbidity index (CCI) 0, 1, and ≥2. Chi-square tests were used to examine the association between CCI and different variables. We used logistic regression and Cox proportional hazard models to determine predictors of 1-month mortality and OS, respectively.
    RESULTS: Among the entire cohort, 65% had CCI 0, 24% had CCI 1, and 11% had CCI ≥2. Thirty-four percent did not receive chemotherapy. Patients with CCI 0 were more likely to receive chemotherapy, especially multiagent chemotherapy and undergo upfront hematopoietic cell transplantation. In multivariate analyses, 1-month mortality and OS were significantly worse with CCI 1 or ≥2, compared with CCI 0 in the entire cohort, as the subgroup of only those patients who received chemotherapy. Younger age, male gender, higher annual income, academic facility, longer travel distance, and acute promyelocytic leukemia were associated with improved OS.
    CONCLUSION: In one of the largest real-world studies of older adults with AML, we demonstrated that greater comorbidity, measured by higher CCI, independently predicted worse early mortality and OS in older patients with AML. Higher CCI was more common with increasing age and correlated with lower likelihood of receiving chemotherapy and hematopoietic cell transplantation. Whether optimal comorbidity management and supportive care may improve outcomes needs to be studied further.
    Keywords:  Acute leukemia; Chemotherapy; Geriatrics; Older adults; Survival
    DOI:  https://doi.org/10.1016/j.clml.2020.07.002
  21. EBioMedicine. 2020 Aug 04. pii: S2352-3964(20)30279-6. [Epub ahead of print]58 102904
    Wiseman DH, Baker SM, Dongre AV, Gurashi K, Storer JA, Somervaille TC, Batta K.
      BACKGROUND: Chronic myelomonocytic leukaemia (CMML) is a clinically heterogeneous stem cell malignancy with overlapping features of myelodysplasia and myeloproliferation. Over 90% of patients carry mutations in epigenetic and/or splicing genes, typically detectable in the Lin-CD34+CD38- immunophenotypic stem cell compartment in which the leukaemia-initiating cells reside. Transcriptional dysregulation at the stem cell level is likely fundamental to disease onset and progression.METHODS: We performed single-cell RNA sequencing on 6826 Lin-CD34+CD38-stem cells from CMML patients and healthy controls using the droplet-based, ultra-high-throughput 10x platform.
    FINDINGS: We found substantial inter- and intra-patient heterogeneity, with CMML stem cells displaying distinctive transcriptional programs. Compared with normal controls, CMML stem cells exhibited transcriptomes characterized by increased expression of myeloid-lineage and cell cycle genes, and lower expression of genes selectively expressed by normal haematopoietic stem cells. Neutrophil-primed progenitor genes and a MYC transcription factor regulome were prominent in stem cells from CMML-1 patients, whereas CMML-2 stem cells exhibited strong expression of interferon-regulatory factor regulomes, including those associated with IRF1, IRF7 and IRF8. CMML-1 and CMML-2 stem cells (stages distinguished by proportion of downstream blasts and promonocytes) differed substantially in both transcriptome and pseudotime, indicating fundamentally different biology underpinning these disease states. Gene expression and pathway analyses highlighted potentially tractable therapeutic vulnerabilities for downstream investigation. Importantly, CMML patients harboured variably-sized subpopulations of transcriptionally normal stem cells, indicating a potential reservoir to restore functional haematopoiesis.
    INTERPRETATION: Our findings provide novel insights into the CMML stem cell compartment, revealing an unexpected degree of heterogeneity and demonstrating that CMML stem cell transcriptomes anticipate disease morphology, and therefore outcome.
    FUNDING: Project funding was supported by Oglesby Charitable Trust, Cancer Research UK, Blood Cancer UK, and UK Medical Research Council.
    Keywords:  CMML; Leukaemia; Stem cells; sc-RNA Seq
    DOI:  https://doi.org/10.1016/j.ebiom.2020.102904
  22. Clin Lymphoma Myeloma Leuk. 2020 Jul 06. pii: S2152-2650(20)30331-1. [Epub ahead of print]
    Genthon A, Brissot E, Malard F, van de Wyngaert Z, Bonnin A, Banet A, Marjanovic Z, Ikhlef S, Lapusan S, Sestili S, Corre E, Paviglianiti A, Adaeva R, 'Hammedi-Bouzina FM, Labopin M, Dulery R, Mohty M, Legrand O.
      BACKGROUND: More than one-third of patients with acute myeloid leukemia (AML) will relapse after allogenic hematopoietic cell transplant (allo-HCT). The main challenge is to overcome disease resistance to achieve a new complete remission while avoiding excessive toxicity. Gemtuzumab ozogamicin (GO), a conjugate of calicheamicin linked to the humanized monoclonal anti-CD33 antibody, has been used for refractory or relapsed AML with promising response rates, but liver toxicity of GO has long been considered a limiting factor.PATIENTS AND METHODS: We included 18 consecutive patients with AML relapsing after a first allo-HCT and treated with fractioned GO (fGO) and intensive chemotherapy. The median age was 40 years (range, 18-65).
    RESULTS: The overall response rate was 72% (13/18), including 7 complete remissions. No death was attributed to treatment toxicity. The main liver toxicity was transient and consisted of transaminase level elevation and hyperbilirubinemia. No cases of veno-occlusive disease were observed after the GO treatment. From the time of salvage treatment initiation, 1- and 2-year OS rates were 54% (95% confidence interval, 28%-74%) and 42% (95% confidence interval, 19%-63%), respectively.
    CONCLUSIONS: Our study suggests the feasibility, efficacy, and safety of an fGO-based salvage regimen combined with intensive chemotherapy in patients with CD33+ AML in the case of early relapse after an allo-HCT.
    Keywords:  AML; Allo-HCT; Gemtuzumab ozogamycin; Relapse; Salvage therapy
    DOI:  https://doi.org/10.1016/j.clml.2020.07.001