bims-tremyl Biomed News
on Therapy resistance biology in myeloid leukemia
Issue of 2020‒08‒02
nineteen papers selected by
Paolo Gallipoli
Barts Cancer Institute, Queen Mary University of London


  1. Med Oncol. 2020 Jul 28. 37(8): 72
    Lapa B, Gonçalves AC, Jorge J, Alves R, Pires AS, Abrantes AM, Coucelo M, Abrunhosa A, Botelho MF, Nascimento-Costa JM, Sarmento-Ribeiro AB.
      Cancer cells alter their metabolism by switching from glycolysis to oxidative phosphorylation (OXPHOS), regardless of oxygen availability. Metabolism may be a molecular target in acute myeloid leukemia (AML), where mutations in metabolic genes have been described. This study evaluated glycolysis and OXPHOS as therapeutic targets. The sensitivity to 2-deoxy-D-glucose (2-DG; glycolysis inhibitor) and oligomycin (OXPHOS inhibitor) was tested in six AML cell lines (HEL, HL-60, K-562, KG-1, NB-4, THP-1). These cells were characterized for IDH1/2 exon 4 mutations, reactive oxygen species, and mitochondrial membrane potential. Metabolic activity was assessed by resazurin assay, whereas cell death and cell cycle were assessed by flow cytometry. Glucose uptake and metabolism-related gene expression were analyzed by 18F-FDG and RT-PCR/qPCR, respectively. No IDH1/2 exon 4 mutations were detected. HEL cells had the highest 18F-FDG uptake and peroxides/superoxide anion levels, whereas THP-1 showed the lowest. 2-DG reduced metabolic activity in all cell lines with HEL, KG-1, and NB-4 being the most sensitive cells. Oligomycin decreased metabolic activity in a cell line-dependent manner, the THP-1 resistant and HL-60 being the most sensitive. Both inhibitors induced apoptosis and cell cycle arrest in a cell line- and compound-dependent manner. 2-DG decreased 18F-FDG uptake in HEL, HL-60, KG-1, and NB-4, while oligomycin increased the uptake in K-562. Metabolism gene expression had different responses to treatments. In conclusion, HEL and KG-1 show to be more glycolytic, whereas HL-60 was more OXPHOS dependent. Results suggest that AML cells reprogram their metabolism to overcome OXPHOS inhibition suggesting that glycolysis may be a better therapeutic target.
    Keywords:  2-Deoxy-D-glucose; Acute myeloid leukemia; Glycolysis; Oligomycin; Oxidative phosphorylation; Therapeutic target
    DOI:  https://doi.org/10.1007/s12032-020-01394-6
  2. Blood. 2020 Jul 30. pii: blood.2019004586. [Epub ahead of print]
    Yoshino S, Yokoyama T, Sunami Y, Takahara T, Nakamura A, Yamazaki Y, Tsutsumi S, Aburatani H, Nakamura T.
      The pseudokinase Trib1 functions as a myeloid oncogene that recruits the E3 ubiquitin ligase COP1 to C/EBPa and interacts with MEK1 to enhance ERK phosphorylation. Close genetic effect of Trib1 on Hoxa9 has been observed in myeloid leukemogenesis where Trib1 overexpression significantly accelerates Hoxa9-induced leukemia onset. However, the mechanism underlying how Trib1 functionally modulates Hoxa9 transcription activity is unclear. Herein, we provide evidence that Trib1 modulates Hoxa9-associated super-enhancers. ChIP-seq analysis identified increased histone H3K27Ac signals at super-enhancers of the Erg, Spns2, Rgl1, and Pik3cd loci, as well as increased mRNA expression of these genes. Modification of super-enhancer activity was mostly achieved via the degradation of C/EBPa p42 by Trib1, with a slight contribution from the MEK/ERK pathway. Silencing of Erg abrogated the growth advantage acquired by Trib1 overexpression, indicating that Erg is a critical downstream target of the Trib1/Hoxa9 axis. Moreover, treatment of acute myeloid leukemia (AML) cells with the BRD4 inhibitor JQ1 showed growth inhibition in a Trib1/Erg-dependent manner both in vitro and in vivo. Upregulation of ERG by TRIB1 was also observed in human AML cell lines, suggesting that Trib1 is a potential therapeutic target of Hoxa9-associated AML. Taken together, our study demonstrates a novel mechanism by which Trib1 modulates chromatin and Hoxa9-driven transcription in myeloid leukemogenesis.
    DOI:  https://doi.org/10.1182/blood.2019004586
  3. Biomedicines. 2020 Jul 24. pii: E245. [Epub ahead of print]8(8):
    Eguchi M, Minami Y, Kuzume A, Chi S.
      FLT3-ITD and FLT3-TKD mutations were observed in approximately 20 and 10% of acute myeloid leukemia (AML) cases, respectively. FLT3 inhibitors such as midostaurin, gilteritinib and quizartinib show excellent response rates in patients with FLT3-mutated AML, but its duration of response may not be sufficient yet. The majority of cases gain secondary resistance either by on-target and off-target abnormalities. On-target mutations (i.e., FLT3-TKD) such as D835Y keep the TK domain in its active form, abrogating pharmacodynamics of type II FLT3 inhibitors (e.g., midostaurin and quizartinib). Second generation type I inhibitors such as gilteritinib are consistently active against FLT3-TKD as well as FLT3-ITD. However, a "gatekeeper" mutation F691L shows universal resistance to all currently available FLT3 inhibitors. Off-target abnormalities are consisted with a variety of somatic mutations such as NRAS, AXL and PIM1 that bypass or reinforce FLT3 signaling. Off-target mutations can occur just in the primary FLT3-mutated clone or be gained by the evolution of other clones. A small number of cases show primary resistance by an FL-dependent, FGF2-dependent, and stromal CYP3A4-mediated manner. To overcome these mechanisms, the development of novel agents such as covalently-coupling FLT3 inhibitor FF-10101 and the investigation of combination therapy with different class agents are now ongoing. Along with novel agents, gene sequencing may improve clinical approaches by detecting additional targetable mutations and determining individual patterns of clonal evolution.
    Keywords:  FMS-like tyrosine kinase 3 (FLT3); acute myeloid leukemia (AML); gilteritinib; quizartinib
    DOI:  https://doi.org/10.3390/biomedicines8080245
  4. Haematologica. 2020 Jul 30. pii: haematol.2020.254623. [Epub ahead of print]
    Onecha E, Rapado I, Morales ML, Carreño-Tarragona G, Martinez-Sanchez P, Gutierrez X, Sáchez Pina JM, Linares M, Gallardo M, Martinez-López J, Ayala R.
      In cases of treatment failure in acute myeloid leukemia (AML), the utility of mutational profiling in primary refractoriness and relapse is not established. We undertook a perspective study using next-generation sequencing (NGS) of clinical follow-up samples (n=91) from 23 patients with AML with therapeutic failure to cytarabine plus idarubicin or fludarabine. Cases of primary refractoriness to treatment were associated with a lower number of DNA variants at diagnosis than cases of relapse (median 1.67 and 3.21, respectively, p=0.029). The most frequently affected pathways in patients with primary refractoriness were signaling, transcription and tumor suppression, whereas methylation and splicing pathways were mainly implicated in relapsed patients. New therapeutic targets, either by an approved drug or within clinical trials, were not identified in any of the cases of refractoriness (0/10); however, 8 potential new targets were found in 5 relapsed patients (5/13) (p=0.027): 1 IDH2, 3 SF3B1, 2 KRAS, 1 KIT and 1 JAK2. Sixty-five percent of all variants detected at diagnosis were not detected at complete response (CR). Specifically, 100% of variants in EZH2, RUNX1, VHL, FLT3, ETV6, U2AF1, PHF6 and SF3B1 disappeared at CR, indicating their potential use as markers to evaluate minimal residual disease (MRD) for follow-up of AML. Molecular follow-up using a custom NGS myeloid panel of 32 genes in the post-treatment evaluation of AML can help in the stratification of prognostic risk, the selection of MRD markers to monitor the response to treatment and guide post-remission strategies targeting AML, and the selection of new drugs for leukemia relapse.
    Keywords:  Acute Myeloid Leukemia; Cytogenetics and Molecular Genetics; clonal evolution; sequencing
    DOI:  https://doi.org/10.3324/haematol.2020.254623
  5. Sci Rep. 2020 Jul 29. 10(1): 12761
    Lauber C, Correia N, Trumpp A, Rieger MA, Dolnik A, Bullinger L, Roeder I, Seifert M.
      Acute myeloid leukemia (AML) is a very heterogeneous and highly malignant blood cancer. Mutations of the DNA methyltransferase DNMT3A are among the most frequent recurrent genetic lesions in AML. The majority of DNMT3A-mutant AML patients shows fast relapse and poor survival, but also patients with long survival or long-term remission have been reported. Underlying molecular signatures and mechanisms that contribute to these survival differences are only poorly understood and have not been studied in detail so far. We applied hierarchical clustering to somatic gene mutation profiles of 51 DNMT3A-mutant patients from The Cancer Genome Atlas (TCGA) AML cohort revealing two robust patient subgroups with profound differences in survival. We further determined molecular signatures that distinguish both subgroups. Our results suggest that FLT3 and/or NPM1 mutations contribute to survival differences of DNMT3A-mutant patients. We observed an upregulation of genes of the p53, VEGF and DNA replication pathway and a downregulation of genes of the PI3K-Akt pathway in short- compared to long-lived patients. We identified that the majority of measured miRNAs was downregulated in the short-lived group and we found differentially expressed microRNAs between both subgroups that have not been reported for AML so far (miR-153-2, miR-3065, miR-95, miR-6718) suggesting that miRNAs could be important for prognosis. In addition, we learned gene regulatory networks to predict potential major regulators and found several genes and miRNAs with known roles in AML pathogenesis, but also interesting novel candidates involved in the regulation of hematopoiesis, cell cycle, cell differentiation, and immunity that may contribute to the observed survival differences of both subgroups and could therefore be important for prognosis. Moreover, the characteristic gene mutation and expression signatures that distinguished short- from long-lived patients were also predictive for independent DNMT3A-mutant AML patients from other cohorts and could also contribute to further improve the European LeukemiaNet (ELN) prognostic scoring system. Our study represents the first in-depth computational approach to identify molecular factors associated with survival differences of DNMT3A-mutant AML patients and could trigger additional studies to develop robust molecular markers for a better stratification of AML patients with DNMT3A mutations.
    DOI:  https://doi.org/10.1038/s41598-020-69691-8
  6. Haematologica. 2020 Jul 30. pii: haematol.2020.252817. [Epub ahead of print]
    Oppliger Leibundgut E, Haubitz M, Burington B, Ottmann OG, Spitzer G, Odenike O, McDevitt MA, Röth A, Snyder DS, Baerlocher GM.
      In a phase-2 study, the telomerase inhibitor imetelstat induced rapid hematologic responses in all patients with essential thrombocythemia who were refractory or intolerant to prior therapies. Significant molecular responses were achieved within 3-6 months in 81% of patients with phenotypic driver mutations in JAK2, CALR and MPL. Here, we investigated the dynamics of additional somatic mutations in response to imetelstat. At study entry, 50% of patients carried 1-5 additional mutations in the genes ASXL1, CBL, DNMT3A, EZH2, IDH1, SF3B1, TET2, TP53 and U2AF1. Three patients with baseline mutations also had late-emerging mutations in TP53, IDH1 and TET2. Most clones with additional mutations were responsive to imetelstat and decreased with the driver mutation, including the poor prognostic ASXL1, EZH2 and U2AF1 mutations while SF3B1 and TP53 mutations were associated with poorer molecular response. Overall, phenotypic driver mutation response was significantly deeper in patients without additional mutations (P = 0.04) and correlated with longer duration of response. In conclusion, this detailed molecular analysis of highly pretreated and partly resistant patients with essential thrombocythemia reveals a high individual patient complexity. Moreover, imetelstat demonstrates potential to inhibit efficiently co-incident mutations occurring in neoplastic clones in patients with essential thrombocythemia. (ClinicalTrials.gov number, NCT01243073 N Engl J Med 2015; 373:920-928, DOI: 10.1056/NEJMoa1503479.).
    Keywords:  Essential Thrombocythemia; Imetelstat; Molecular Response; Mutation
    DOI:  https://doi.org/10.3324/haematol.2020.252817
  7. Leukemia. 2020 Jul 30.
    Heuser M, Palmisiano N, Mantzaris I, Mims A, DiNardo C, Silverman LR, Wang ES, Fiedler W, Baldus C, Schwind S, Pardee T, Perl AE, Cai C, Kaulfuss S, Lagkadinou E, Rentzsch C, Wagner M, Wilkinson G, Wu B, Jeffers M, Genvresse I, Krämer A.
      The mutant IDH1 (mIDH1) inhibitor BAY1436032 demonstrated robust activity in preclinical AML models, supporting clinical evaluation. In the current dose-escalation study, BAY1436032 was orally administered to 27 mIDH1 AML subjects across 4 doses ranging from 300 to 1500 mg twice-daily. BAY1436032 exhibited a relatively short half-life and apparent non-linear pharmacokinetics after continuous dosing. Most subjects experienced only partial target inhibition as indicated by plasma R-2HG levels. BAY1436032 was safe and a maximum tolerated dose was not identified. The median treatment duration for all subjects was 3.0 months (0.49-8.5). The overall response rate was 15% (4/27; 1 CRp, 1 PR, 2 MLFS), with responding subjects experiencing a median treatment duration of 6.0 months (3.9-8.5) and robust R-2HG decreases. Thirty percent (8/27) achieved SD, with a median treatment duration of 5.5 months (3.1-7.0). Degree of R-2HG inhibition and clinical benefit did not correlate with dose. Although BAY1436032 was safe and modestly effective as monotherapy, the low overall response rate and incomplete target inhibition achieved at even the highest dose tested do not support further clinical development of this investigational agent in AML.
    DOI:  https://doi.org/10.1038/s41375-020-0996-5
  8. Blood. 2020 Jul 30. pii: blood.2020006158. [Epub ahead of print]
    Sallman DA, McLemore AF, Aldrich AL, Komrokji RS, McGraw KL, Dhawan A, Geyer S, Hou HA, Eksioglu EA, Sullivan A, Warren S, MacBeth KJ, Meggendorfer M, Haferlach T, Boettcher S, Ebert BL, Al-Ali N, Lancet JE, Cleveland JL, Padron E, List AF.
      Somatic gene mutations are key determinants of outcome in patients with myelodysplastic syndromes (MDS) and secondary AML (sAML). In particular, patients with TP53 mutations represent a distinct molecular cohort with uniformly poor prognosis. The precise pathogenetic mechanisms underlying these inferior outcomes have not been delineated. Here we characterize the immunological features of the malignant clone and alterations in the immune microenvironment in TP53 mutant and wild type MDS and sAML patients. Notably, PDL1 expression is significantly increased in hematopoietic stem cells of TP53 mutant patients, which is associated with MYC upregulation and marked down-regulation of MYC's negative regulator miR-34a, a p53 transcription target. Notably, TP53 mutant patients display significantly reduced numbers of bone marrow infiltrating OX40+ cytotoxic T-cells and helper T-cells, as well as decreased ICOS+ and 4-1BB+ NK cells. Further, highly immunosuppressive regulatory T-cells (i.e., ICOSHigh/PD-1neg) and MDSCs (PD-1low) are expanded in TP53 mutant cases. Finally, a higher proportion of bone marrow infiltrating ICOSHigh/PD-1neg Tregs is a highly significant independent predictor of overall survival. We conclude the microenvironment of TP53 mutant MDS and sAML has an immune privileged, evasive phenotype that may be a primary driver of poor outcomes, and submit that immunomodulatory therapeutic strategies may offer a benefit for this molecularly-defined subpopulation.
    DOI:  https://doi.org/10.1182/blood.2020006158
  9. Nature. 2020 Jul 29.
    Kadosh E, Snir-Alkalay I, Venkatachalam A, May S, Lasry A, Elyada E, Zinger A, Shaham M, Vaalani G, Mernberger M, Stiewe T, Pikarsky E, Oren M, Ben-Neriah Y.
      Somatic mutations in p53, which inactivate the tumour-suppressor function of p53 and often confer oncogenic gain-of-function properties, are very common in cancer1,2. Here we studied the effects of hotspot gain-of-function mutations in Trp53 (the gene that encodes p53 in mice) in mouse models of WNT-driven intestinal cancer caused by Csnk1a1 deletion3,4 or ApcMin mutation5. Cancer in these models is known to be facilitated by loss of p533,6. We found that mutant versions of p53 had contrasting effects in different segments of the gut: in the distal gut, mutant p53 had the expected oncogenic effect; however, in the proximal gut and in tumour organoids it had a pronounced tumour-suppressive effect. In the tumour-suppressive mode, mutant p53 eliminated dysplasia and tumorigenesis in Csnk1a1-deficient and ApcMin/+ mice, and promoted normal growth and differentiation of tumour organoids derived from these mice. In these settings, mutant p53 was more effective than wild-type p53 at inhibiting tumour formation. Mechanistically, the tumour-suppressive effects of mutant p53 were driven by disruption of the WNT pathway, through preventing the binding of TCF4 to chromatin. Notably, this tumour-suppressive effect was completely abolished by the gut microbiome. Moreover, a single metabolite derived from the gut microbiota-gallic acid-could reproduce the entire effect of the microbiome. Supplementing gut-sterilized p53-mutant mice and p53-mutant organoids with gallic acid reinstated the TCF4-chromatin interaction and the hyperactivation of WNT, thus conferring a malignant phenotype to the organoids and throughout the gut. Our study demonstrates the substantial plasticity of a cancer mutation and highlights the role of the microenvironment in determining its functional outcome.
    DOI:  https://doi.org/10.1038/s41586-020-2541-0
  10. Leukemia. 2020 Jul 29.
    Yun S, Geyer SM, Komrokji RS, Al Ali NH, Song J, Hussaini M, Sweet KL, Lancet JE, List AF, Padron E, Sallman DA.
      The implementation of next-generation sequencing (NGS) has influenced diagnostic, prognostic, and therapeutic decisions in myeloid malignancies. However, the clinical relevance of serial molecular annotation in patients with myelodysplastic syndrome (MDS) undergoing active treatment is unknown. MDS or secondary acute myeloid leukemia (sAML) patients who had at least two NGS assessments were identified. Outcomes according to mutation clearance (NGS-) on serial assessment were investigated. Univariate and multivariate Cox regression models were used to evaluate the prognostic impact of NGS trajectory on overall survival (OS). A total of 157 patients (MDS [n = 95]; sAML [n = 52]; CMML [n = 10]) were identified, with 93% of patients receiving treatment between NGS assessments. Magnitude of VAF delta from baseline was significantly associated with quality of response to treatment. Patients achieving NGS- had significantly improved OS compared to patients with mutation persistence (median OS not reached vs. 18.5 months; P = 0.002), which was confirmed in multivariate analysis (HR,0.14; 95%CI = 0.03-0.56; P = 0.0064). Serial TP53 VAF evaluation predicts outcomes with TP53 clearance representing an independent covariate for superior OS (HR,0.22; 95%CI = 0.05-0.99; P = 0.048). Collectively, our study highlights the clinical value of serial NGS during treatment and warrants prospective validation of NGS negativity as a biomarker for treatment outcome.
    DOI:  https://doi.org/10.1038/s41375-020-0997-4
  11. Blood Cells Mol Dis. 2020 Jul 14. pii: S1079-9796(20)30309-0. [Epub ahead of print]85 102477
    Kuang Y, Han X, Cao P, Xiong D, Peng Y, Liu Z, Xu Z, Liang L, Roy M, Liu J, Nie L, Zhang J.
      Chronic myeloid leukemia (CML) is a kind of myeloproliferative disorder caused by a constitutively active BCR-ABL tyrosine kinase. Tyrosine kinase inhibitors (TKIs), imatinib and its derivatives, have achieved great progress in the treatment of CML. However, many CML patients do not respond to TKIs alone. p19INK4d, a cyclin-dependent kinase inhibitor, plays important roles in proliferation, DNA damage repair, apoptosis and cell differentiation, but its role in CML is unknown. Herein, we found that the expression of p19INK4d in CML patients was significantly lower than that in healthy controls. p19INK4d overexpression inhibits cell proliferation through cell cycle arrest, and cooperates with imatinib to inhibit CML more effectively in vitro and in vivo. Mechanistically, p19INK4d decreased the expression of BCR-ABL and its downstream molecules p-Mek1/2, moreover, the expression of Gli-1, c-myc, MUC1, Shh and TC48 also reduced significantly. Collectively, p19INK4d inhibits proliferation and enhances imatinib efficacy in the treatment of CML. These findings maybe have implications for developing potential targets to increase imatinib sensitivity for CML.
    Keywords:  BCR-ABL; CML; Imatinib; Proliferation; p19(INK4d)
    DOI:  https://doi.org/10.1016/j.bcmd.2020.102477
  12. Cancer Rep (Hoboken). 2019 Apr;2(2): e1139
    Nemkov T, D'Alessandro A, Reisz JA.
      BACKGROUND: Carcinogenic transformation of white blood cells during hematopoiesis leads to the development of leukemia, a cancer characterized by incompetent immune cells and a disruption of normal bone marrow function. Leukemias are diverse in type, affected population, prognosis, and treatment regimen, yet a common theme in leukemia is the dysregulated metabolism of leukemic cells and leukemic stem cells with respect to their noncancerous counterparts.RECENT FINDINGS: In this review, we highlight current findings that elucidate metabolic traits unique to the four major types of leukemia, which confer carcinogenic survival but can be potentially exploited for therapeutic intervention. These metabolic features can work in conjunction with or be independent of unique aspects of the bone marrow microenvironment that can also influence cell survival and proliferation, thus sustaining carcinogenesis.
    CONCLUSION: Deepening our understanding of the interactions of leukemias with their niche environments in vivo will inform future treatments for leukemia, particularly for those that are refractive to tyrosine kinase inhibitors and other therapeutic mainstays.
    Keywords:  leukemia; mass spectrometry; metabolism; metabolomics; stable isotope tracing; tumor microenvironment
    DOI:  https://doi.org/10.1002/cnr2.1139
  13. Blood Res. 2020 Jul 31. 55(S1): S14-S18
    Park S, Cho BS, Kim HJ.
      Despite expanding knowledge in the molecular landscape of acute myeloid leukemia (AML) and an increasing understanding of leukemogenic pathways, little has changed in the treatment of AML in the last 40 years. Since introduction in the 1970s, combination chemotherapy consisting of anthracycline and cytarabine has been the mainstay of treatment, with major therapeutic advances based on improving supportive care rather than the introduction of novel therapeutics. Over the last decades, there have been extensive efforts to identify specific target mutations or pathways with the aim of improving clinical outcomes. Finally, after a prolonged wait, we are witnessing the next wave of AML treatment, characterized by a more "precise" and "personalized" understanding of the unique molecular or genetic mapping of individual patients. This new trend has since been further facilitated, with four new FDA approvals granted in 2017 in AML therapeutics. Currently, a total of eight targeted agents have been approved since 2017 (as of Jan. 2020). In this review, we will briefly discuss these newer agents in the context of their indication and the basis of their approval.
    Keywords:  Acute myeloid leukemia; New FDA approvals
    DOI:  https://doi.org/10.5045/br.2020.S003
  14. Cell Rep. 2020 Jul 28. pii: S2211-1247(20)30938-4. [Epub ahead of print]32(4): 107957
    Flosbach M, Oberle SG, Scherer S, Zecha J, von Hoesslin M, Wiede F, Chennupati V, Cullen JG, List M, Pauling JK, Baumbach J, Kuster B, Tiganis T, Zehn D.
      Manipulating molecules that impact T cell receptor (TCR) or cytokine signaling, such as the protein tyrosine phosphatase non-receptor type 2 (PTPN2), has significant potential for advancing T cell-based immunotherapies. Nonetheless, it remains unclear how PTPN2 impacts the activation, survival, and memory formation of T cells. We find that PTPN2 deficiency renders cells in vivo and in vitro less dependent on survival-promoting cytokines, such as interleukin (IL)-2 and IL-15. Remarkably, briefly ex vivo-activated PTPN2-deficient T cells accumulate in 3- to 11-fold higher numbers following transfer into unmanipulated, antigen-free mice. Moreover, the absence of PTPN2 augments the survival of short-lived effector T cells and allows them to robustly re-expand upon secondary challenge. Importantly, we find no evidence for impaired effector function or memory formation. Mechanistically, PTPN2 deficiency causes broad changes in the expression and phosphorylation of T cell expansion and survival-associated proteins. Altogether, our data underline the therapeutic potential of targeting PTPN2 in T cell-based therapies to augment the number and survival capacity of antigen-specific T cells.
    Keywords:  GWAS; Protein tyrosine phosphatase non‑receptor type 2 (PTPN2); T cell memory; adoptive T cell transfer; autoimmunity; effector T cells; immunotherapy; phosphoproteome; programmed T cell expansion; single point mutation
    DOI:  https://doi.org/10.1016/j.celrep.2020.107957
  15. Blood. 2020 Jul 31. pii: blood.2019000991. [Epub ahead of print]
    Warren JT, Link DC.
      Clonal hematopoiesis is common in older persons and is associated with an increased risk of hematologic cancer. Here, we review studies establishing an association between clonal hematopoiesis and hematopoietic malignancy, discuss features of clonal hematopoiesis that are predictive of leukemic progression, and explore the role of hematopoietic stressors in the evolution of clonal hematopoiesis to acute myeloid leukemia or myelodysplastic syndrome. Clonal hematopoiesis due to point mutations or structural variants, such as copy number alterations, are associated with an approximately 10-fold increased risk of hematopoietic malignancy. Although the absolute risk of hematopoietic malignancy is low, certain features of clonal hematopoiesis may confer a higher risk of transformation, including the presence of TP53 or splicesome gene mutations, a variant allele fraction greater than 10%, the presence of multiple mutations, and altered red blood indices. Clonal hematopoiesis in the setting of peripheral blood cytopenias carries a very high risk of progression to a myeloid malignancy and merits close observation. There is emerging evidence to suggest the hematopoietic stressors contribute both to the development of clonal hematopoiesis and progression to hematopoietic malignancy. Specifically, there is evidence that genotoxic stress from chemotherapy or radiation therapy, ribosome biogenesis stress, and possibly inflammation may increase the risk of transformation from clonal hematopoiesis to a myeloid malignancy. Models that incorporate features of clonal hematopoiesis along with an assessment of hematopoietic stressors may eventually help predict and prevent the development of hematopoietic malignancies.
    DOI:  https://doi.org/10.1182/blood.2019000991
  16. Nature. 2020 Jul;583(7818): 699-710
    , Moore JE, Purcaro MJ, Pratt HE, Epstein CB, Shoresh N, Adrian J, Kawli T, Davis CA, Dobin A, Kaul R, Halow J, Van Nostrand EL, Freese P, Gorkin DU, Shen Y, He Y, Mackiewicz M, Pauli-Behn F, Williams BA, Mortazavi A, Keller CA, Zhang XO, Elhajjajy SI, Huey J, Dickel DE, Snetkova V, Wei X, Wang X, Rivera-Mulia JC, Rozowsky J, Zhang J, Chhetri SB, Zhang J, Victorsen A, White KP, Visel A, Yeo GW, Burge CB, Lécuyer E, Gilbert DM, Dekker J, Rinn J, Mendenhall EM, Ecker JR, Kellis M, Klein RJ, Noble WS, Kundaje A, Guigó R, Farnham PJ, Cherry JM, Myers RM, Ren B, Graveley BR, Gerstein MB, Pennacchio LA, Snyder MP, Bernstein BE, Wold B, Hardison RC, Gingeras TR, Stamatoyannopoulos JA, Weng Z.
      The human and mouse genomes contain instructions that specify RNAs and proteins and govern the timing, magnitude, and cellular context of their production. To better delineate these elements, phase III of the Encyclopedia of DNA Elements (ENCODE) Project has expanded analysis of the cell and tissue repertoires of RNA transcription, chromatin structure and modification, DNA methylation, chromatin looping, and occupancy by transcription factors and RNA-binding proteins. Here we summarize these efforts, which have produced 5,992 new experimental datasets, including systematic determinations across mouse fetal development. All data are available through the ENCODE data portal (https://www.encodeproject.org), including phase II ENCODE1 and Roadmap Epigenomics2 data. We have developed a registry of 926,535 human and 339,815 mouse candidate cis-regulatory elements, covering 7.9 and 3.4% of their respective genomes, by integrating selected datatypes associated with gene regulation, and constructed a web-based server (SCREEN; http://screen.encodeproject.org) to provide flexible, user-defined access to this resource. Collectively, the ENCODE data and registry provide an expansive resource for the scientific community to build a better understanding of the organization and function of the human and mouse genomes.
    DOI:  https://doi.org/10.1038/s41586-020-2493-4
  17. Nat Commun. 2020 Jul 29. 11(1): 3778
    Pavani G, Laurent M, Fabiano A, Cantelli E, Sakkal A, Corre G, Lenting PJ, Concordet JP, Toueille M, Miccio A, Amendola M.
      Targeted genome editing has a great therapeutic potential to treat disorders that require protein replacement therapy. To develop a platform independent of specific patient mutations, therapeutic transgenes can be inserted in a safe and highly transcribed locus to maximize protein expression. Here, we describe an ex vivo editing approach to achieve efficient gene targeting in human hematopoietic stem/progenitor cells (HSPCs) and robust expression of clinically relevant proteins by the erythroid lineage. Using CRISPR-Cas9, we integrate different transgenes under the transcriptional control of the endogenous α-globin promoter, recapitulating its high and erythroid-specific expression. Erythroblasts derived from targeted HSPCs secrete different therapeutic proteins, which retain enzymatic activity and cross-correct patients' cells. Moreover, modified HSPCs maintain long-term repopulation and multilineage differentiation potential in transplanted mice. Overall, we establish a safe and versatile CRISPR-Cas9-based HSPC platform for different therapeutic applications, including hemophilia and inherited metabolic disorders.
    DOI:  https://doi.org/10.1038/s41467-020-17552-3
  18. Nat Metab. 2020 Jul 27.
    Orozco JM, Krawczyk PA, Scaria SM, Cangelosi AL, Chan SH, Kunchok T, Lewis CA, Sabatini DM.
      The mechanistic target of rapamycin complex 1 (mTORC1) kinase regulates cell growth by setting the balance between anabolic and catabolic processes. To be active, mTORC1 requires the environmental presence of amino acids and glucose. While a mechanistic understanding of amino acid sensing by mTORC1 is emerging, how glucose activates mTORC1 remains mysterious. Here, we used metabolically engineered human cells lacking the canonical energy sensor AMP-activated protein kinase to identify glucose-derived metabolites required to activate mTORC1 independent of energetic stress. We show that mTORC1 senses a metabolite downstream of the aldolase and upstream of the GAPDH-catalysed steps of glycolysis and pinpoint dihydroxyacetone phosphate (DHAP) as the key molecule. In cells expressing a triose kinase, the synthesis of DHAP from DHA is sufficient to activate mTORC1 even in the absence of glucose. DHAP is a precursor for lipid synthesis, a process under the control of mTORC1, which provides a potential rationale for the sensing of DHAP by mTORC1.
    DOI:  https://doi.org/10.1038/s42255-020-0250-5
  19. Biol Blood Marrow Transplant. 2020 Jul 23. pii: S1083-8791(20)30448-1. [Epub ahead of print]
    Jiang G, Capo-Chichi JM, Liu A, Atenafu EG, Kumar R, Minden MD, Chang H.
      NPM1 mutation status and allelic ratio (AR) of FLT3-Internal Tandem Duplication (FLT3-ITD) are routinely tested for disease risk stratification in patients with normal karyotype (NK) acute myeloid leukemia (AML); however, the predictive impact of immunophenotypic markers on different NPM1/FLT3 genotypes remains unclear. We performed a retrospective analysis of 423 NK-AML patients sub-classified into groups based on their NPM1/FLT3 genotypes. Allogenic HSCT was performed in 124/423 (29%) patients and was significantly associated with longer event free survival (EFS) and overall survival (OS), except for patients with the favourable genotype defined by mutated NPM1 (NPM1mut) combined with normal FLT3 status (FLT3-ITDneg) or FLT3-ITD AR < 0.5 (FLT3-ITDlow). A subset of the AML patients bearing the favourable NPM1mut/FLT3-ITDneg/low genotype share similar outcome with AML patients that have the intermediate FLT3/NPM1 genotype defined by normal NPM1 (NPM1wt) and FLT3-ITDneg/low. In these individuals, the lack of CD13 expression (CD13neg) was associated with shorter EFS (P=0.041) and OS (P=0.017). CD13neg was an independent predictor for shorter OS (P=0.028, HR=1.985).
    Keywords:  AML; FLT3-ITD; NPM1; immunophenotyping; prognosis
    DOI:  https://doi.org/10.1016/j.bbmt.2020.07.017