bims-tremyl Biomed News
on Therapy resistance biology in myeloid leukemia
Issue of 2020‒12‒13
eighteen papers selected by
Paolo Gallipoli
Barts Cancer Institute, Queen Mary University of London

  1. Curr Opin Hematol. 2020 Dec 03.
      PURPOSE OF REVIEW: Myeloid malignancies comprise a spectrum of genetically heterogeneous disorders marked by the stepwise acquisition of somatic mutations and clonal evolution. The blood and bone marrow of patients typically consists of a mix of different clones and subclones along the path of clonal evolution that cannot be deconvoluted with most current approaches. Here, we review the application of induced pluripotent stem cell (iPSC) technology to the study of the clonal architecture and clonal evolution of these diseases, focusing on myelodysplastic syndromes and acute myeloid leukemia.RECENT FINDINGS: Reprogramming to pluripotency allows capture of the genomes of single somatic cells into stable iPSC lines. In addition, precise genome editing can introduce specific driver mutations, isolated, and in combinations, into normal iPSCs. Studies utilizing these approaches have elucidated the clonal composition and mutational order in patients with myeloid neoplasms. Importantly, they have also enabled functional interrogation of the cellular and molecular consequences of individual mutations and their combinations and allowed testing of the effects of drugs on distinct disease clones.
    SUMMARY: Human iPSCs are important tools to elucidate the mechanisms of progression from normal to malignant haematopoiesis and empower drug testing and drug discovery.
  2. Bone Marrow Transplant. 2020 Dec 07.
      We evaluated standard-of-care (SOC) treatment with or without midostaurin to prevent relapse following allogeneic hematopoietic stem cell transplant (alloHSCT) in patients with acute myeloid leukemia (AML) harboring internal tandem duplication (ITD) in FLT3. Adults (aged 18-70 years) who received alloHSCT in first complete remission, had achieved hematologic recovery, and were transfusion independent were randomized to receive SOC with or without midostaurin (50 mg twice daily) continuously in twelve 4-week cycles. The primary endpoint was relapse-free survival (RFS) 18 months post-alloHSCT. Sixty patients were randomized (30/arm); 30 completed all 12 cycles (midostaurin + SOC, n = 16; SOC, n = 14). The estimated 18-month RFS (95% CI) was 89% (69-96%) in the midostaurin arm and 76% (54-88%) in the SOC arm (hazard ratio, 0.46 [95% CI, 0.12-1.86]; P = 0.27); estimated relapse rates were 11% and 24%, respectively. Inhibition of FLT3 phosphorylation to <70% of baseline (achieved by 50% of midostaurin-treated patients) was associated with improved RFS. The most common serious adverse events were diarrhea, nausea, and vomiting. Rates of graft-vs-host disease were similar between both arms (midostaurin + SOC, 70%; SOC, 73%). The addition of midostaurin maintenance therapy following alloHSCT may provide clinical benefit in some patients with FLT3-ITD AML. ( identifier: NCT01883362).
  3. J Clin Invest. 2020 Dec 10. pii: 140242. [Epub ahead of print]
      How particular bone marrow niche factors contribute to the leukemogenic activities of leukemia-initiating cells (LICs) remain largely unknown. Here, we showed that ATP levels were markedly increased in the bone marrow niches of mice with acute myeloid leukemia (AML), and LICs preferred to localizing to the endosteal niche with relatively high ATP levels, as indicated by a sensitive ATP indicator. ATP could efficiently induce the influx of ions into LICs in an MLL-AF9-induced murine AML model via the ligand-gated ion channel P2X7. P2x7 deletion led to notably impaired homing and self-renewal capacities of LICs and contributed to an ~5-fold decrease in the number of functional LICs but had no effect on normal hematopoiesis. ATP-P2X7 signaling enhanced the calcium flux-mediated phosphorylation of CREB, which further transactivated the Phgdh expression to maintain serine metabolism and LIC fates. P2X7-knockdown resulted in a markedly extended survival of recipients transplanted with either human AML cell lines or primary leukemia cells. Blockade of ATP-P2X7 signaling could efficiently inhibit leukemogenesis. Here, we provide a unique perspective for understanding how ATP-P2X7 signaling sustains the LIC activities, which may benefit the development of specific strategies for targeting LICs or other types of cancer stem cells.
    Keywords:  Hematology; Leukemias; Stem cells
  4. FEBS Open Bio. 2020 Dec 01.
      Leukemic stem cells (LSCs) are a very rare cell population that result in the development of acute myeloid leukemia (AML). The selective targeting of drivers in LSCs with small molecule inhibitors holds promise for treatment of AML. Recently, we reported the identification of inhibitors of the histone lysine demethylase JMJD1C that preferentially kill MLL rearranged acute leukemia cells. Here, we report the identification of JMJD1C Jumomji domain Modulator 7 (JDM-7). Surface plasmon resonance (SPR) analysis showed that JDM-7 binds to JMJD1C and its family homolog JMJD1B. JDM-7 did not significantly suppress cell proliferation in liquid cell culture at higher doses, but led to a significant decrease in semi-solid colony formation experiments at lower concentrations. Moreover, low doses of JDM-7 did not suppress the proliferation of erythroid progenitor cells. We identified that JDM-7 downregulates the LSC self-renewal gene HOXA9 in leukemia cells. We further found that the structure of JDM-7 is similar to that of Tadalafil, an FDA approved drug. Molecular docking and surface plasmon resonance (SPR) analysis showed that Tadalafil binds to JMJD1C. Moreover, like JDM-7, Tadalafil suppressed colony formation of leukemia cells in semi-solid cell culture at a concentration that did not affect primary umbilical cord blood cells. In summary, we have identified JDM-7 and Tadalafil as potential JMJD1C modulators that selectively inhibit the growth of LSCs.
    Keywords:  JMJD1B; JMJD1C; Leukemic stem cells (LSCs); histone demethylases; small molecular compounds
  5. Blood. 2020 Dec 10. 136(24): 2764-2773
      Hematopoietic clones with leukemogenic mutations arise in healthy people as they age, but progression to acute myeloid leukemia (AML) is rare. Recent evidence suggests that the microenvironment may play an important role in modulating human AML population dynamics. To investigate this concept further, we examined the combined and separate effects of an oncogene (c-MYC) and exposure to interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and stem cell factor (SCF) on the experimental genesis of a human AML in xenografted immunodeficient mice. Initial experiments showed that normal human CD34+ blood cells transduced with a lentiviral MYC vector and then transplanted into immunodeficient mice produced a hierarchically organized, rapidly fatal, and serially transplantable blast population, phenotypically and transcriptionally similar to human AML cells, but only in mice producing IL-3, GM-CSF, and SCF transgenically or in regular mice in which the cells were exposed to IL-3 or GM-CSF delivered using a cotransduction strategy. In their absence, the MYC+ human cells produced a normal repertoire of lymphoid and myeloid progeny in transplanted mice for many months, but, on transfer to secondary mice producing the human cytokines, the MYC+ cells rapidly generated AML. Indistinguishable diseases were also obtained efficiently from both primitive (CD34+CD38-) and late granulocyte-macrophage progenitor (GMP) cells. These findings underscore the critical role that these cytokines can play in activating a malignant state in normally differentiating human hematopoietic cells in which MYC expression has been deregulated. They also introduce a robust experimental model of human leukemogenesis to further elucidate key mechanisms involved and test strategies to suppress them.
  6. Best Pract Res Clin Haematol. 2020 Dec;pii: S1521-6926(20)30092-X. [Epub ahead of print]33(4): 101224
      Despite the approval of a number of new targeted therapies for acute myeloid leukemia (AML), median overall survival still remains poor, ranging from 12 to 18 months in most patients. Based on the success of blinatumomab, the CD19-targeted bispecific antibody for the treatment of acute lymphoblastic leukemia, the development of several CD33-targeted bispecific antibodies for AML are being investigated in clinical trials. In this review article of CD33-targeted bispecific antibodies, we describe the rationale for targeting CD3 x CD33, summarize the data from four ongoing phase 1 studies, review the major toxicity associated with CD33-targeted bispecific antibody therapy of cytokine release syndrome (CRS) and steps to mitigate CRS, and describe possible mechanisms of resistance to CD33-targeted bispecific antibody therapy. Future development to try to improve outcomes include combination therapies to reduce the tumor burden prior to starting treatment, combining with immune checkpoint inhibition therapy such as anti-PD-1/PDL1 antibodies, and the use of second generation bispecific antibodies that target two different antigens and recruit other effector cells such as nature killer cells and macrophages.
    Keywords:  Acute myeloid leukemia; Bispecific antibodies; CD33; Cytokine release syndrome; Immunotherapy
  7. Leukemia. 2020 Dec 09.
      Most AML patients exhibit mutational activation of the PI3K/AKT signaling pathway, which promotes downstream effects including growth, survival, DNA repair, and resistance to chemotherapy. Herein we demonstrate that the inv(16)/KITD816Y AML mouse model exhibits constitutive activation of PI3K/AKT signaling, which was enhanced by chemotherapy-induced DNA damage through DNA-PK-dependent AKT phosphorylation. Strikingly, inhibitors of either PI3K or DNA-PK markedly reduced chemotherapy-induced AKT phosphorylation and signaling leading to increased DNA damage and apoptosis of inv(16)/KITD816Y AML cells in response to chemotherapy. Consistently, combinations of chemotherapy and PI3K or DNA-PK inhibitors synergistically inhibited growth and survival of clonogenic AML cells without substantially inhibiting normal clonogenic bone marrow cells. Moreover, treatment of inv(16)/KITD816Y AML mice with combinations of chemotherapy and PI3K or DNA-PK inhibitors significantly prolonged survival compared to untreated/single-treated mice. Mechanistically, our findings implicate that constitutive activation of PI3K/AKT signaling driven by mutant KIT, and potentially other mutational activators such as FLT3 and RAS, cooperates with chemotherapy-induced DNA-PK-dependent activation of AKT to promote survival, DNA repair, and chemotherapy resistance in AML. Hence, our study provides a rationale to select AML patients exhibiting constitutive PI3K/AKT activation for simultaneous treatment with chemotherapy and inhibitors of DNA-PK and PI3K to improve chemotherapy response and clinical outcome.
  8. Blood Adv. 2020 Dec 08. 4(23): 6000-6008
      Acute erythroid leukemia (AEL) is a rare subtype of acute myeloid leukemia (AML) primarily affecting older adults and was previously classified into erythroid/myeloid and pure erythroid subtypes. In this pediatric AEL study, we evaluated morphologic, immunophenotypic, cytogenetic, molecular, and clinical data of 24 (1.2%) cases from all cases undergoing central pathology review in Children's Oncology Group trials AAML0531 and AAML1031. Of 24 cases, 5 had a pure erythroid phenotype, and 19 had an erythroid/myeloid phenotype. NUP98 fusions were highly enriched in patients with AEL, occurring in 7 of 22 cases for which molecular data were available (31.8% vs 6.7% in other AML subtypes). Of 5 cases of pure erythroid leukemias (PELs), 3 had NUP98 fusions, and 4 had complex karyotypes. Erythroid/myeloid leukemias were reclassified by using the 2017 World Health Organization hematopathology classification as: myelodysplastic syndrome (MDS) with excess blasts-1 (n = 3), MDS with excess blasts-2 (n = 7), AML (nonerythroid, n = 5), and unknown MDS/AML (n = 4); the 5 cases of nonerythroid AML included 1 with an NUP98-NSD1 fusion, 2 with myelodysplasia-related changes, and 1 with a complex karyotype. Three cases of MDS with excess blasts-2 also had NUP98 rearrangements. WT1 mutations were present in 5 of 14 cases, all erythroid/myeloid leukemia. Outcomes assessment revealed statistically poorer overall survival (5-year, 20% ± 36% vs 66% ± 23%; P = .004) and event-free survival (5-year, 20% ± 36% vs 46% ± 23%; P = .019) for those with PEL than those with erythroid/myeloid leukemia. Our study supports that AEL is a morphologically and genetically heterogeneous entity that is enriched in NUP98 fusions, with the pure erythroid subtype associated with particularly adverse outcomes.
  9. Leuk Res. 2020 Nov 22. pii: S0145-2126(20)30185-5. [Epub ahead of print]100 106480
      Central nervous system (CNS) involvement in patients with acute myeloid leukemia (AML) varies, ranging from 0.6%-46%. Leukocyte immunoglobulin-like receptor B4 (LILRB4) has been shown to be critical in orchestration of infiltration of AML cells into the CNS in animal models, however it is unknown if an association exists between LILRB4 and CNS involvement (CNS+) in human patients with AML. LILRB4 was measured by flow cytometry in a heterogeneous population of fifty-six AML patients. Patients were then followed clinically for the development of CNS + . LILRB4 was positive in 91 % of patients with CNS + compared to 38 % without CNS involvement (p < 0.002). In logistic analysis: age, BMI, serum albumin and positive LILRB4 were predictive for CNS+ [OR, 95 % CI, p-value]: 0.95, 0.92-0.99, p < 0.01; 0.85, 0.73-0.998, p < 0.05; 0.23, 0.066-0.78, p < 0.02; 16.46, 1.93-140.2, p < 0.02, respectively. This finding of the association of LILRB4 with CNS + in combination with earlier findings suggests that LILRB4 has a mechanistic role in infiltration of the CNS and may provide insight into the pathogenesis of AML seeding the CNS. Moreover, this proof of concept and the findings in the present study may lead to the development of innovative and novel therapies to improve the lives of patients with AML.
    Keywords:  Clinical results; Molecular genetics; Myeloid leukemias and dysplasias; Prognostication
  10. Biomark Res. 2020 Nov 25. 8(1): 65
      Recently, novel drugs like venetoclax plus 5-azacytidine (VA) were reported to have promising efficacy in refractory acute myeloid leukemia (AML). However, there are still some cases presented with novel drugs resistance, and its genetics composition and clinical phenotype are urging to study. We described a 58-year-old patient who was resistant to intensive chemotherapy. This refractory AML was presented with the persistence of RUNX1, IDH1 and DNMT3A mutations. RUNX1 mutations disappeared and leukemia cutis ensued after multiple chemotherapies. Leukemia cutis exhibited NRAS mutations in addition to IDH1 and DNMT3A mutations. With the VA salvage treatment, platelets were recovered to the normal level and blasts in bone marrow and peripheral blood were moderately controlled. However, leukemia cutis did not resolve. Unexpectedly, BM blasts obtained the new NRAS mutations after VA treatment, and consequently experienced leukostasis with two distinct leukemia clones. After survival of 230 days, this patient died because of spontaneous cerebral hemorrhage. This case highlights presentation of leukemia cutis with simultaneous mutations of IDH1, DNMT3A and NRAS in AML patients might act as a resistant niche to avoid the toxicity of multiple drugs including VA. There is unmet need to validate this result in the clinical trials or a large cohort of patients in the future.
    Keywords:  Acute myeloid leukemia; BCL-2 inhibitors; Leukemia cutis
  11. J Biol Chem. 2020 Dec 10. pii: jbc.RA120.015285. [Epub ahead of print]
      BCR-Abl is a driver oncogene that causes chronic myeloid leukemia and a subset of acute lymphoid leukemias. Although tyrosine kinase inhibitors provide an effective treatment for these diseases, they generally do not kill leukemic stem cells, the cancer-initiating cells that compete with normal hematopoietic stem cells for the bone marrow niche. New strategies to target cancers driven by BCR-Abl are therefore urgently needed.  We performed a small molecule screen based on competition between isogenic untransformed cells and BCR-Abl-transformed cells, and identified several compounds that selectively impair the fitness of BCR-Abl-transformed cells. Interestingly, systems-level analysis of one of these novel compounds, DJ34, revealed that it induced depletion of c-Myc and activation of p53. DJ34-mediated c-Myc depletion occurred in a wide range of tumor cell types, including lymphoma, lung, glioblastoma, breast cancer, and several forms of leukemia, with primary leukemic stem cells being particularly sensitive to DJ34. Further analyses revealed that DJ34 interferes with c-Myc synthesis at the level of transcription, and we provide data showing that DJ34 is a DNA intercalator and topoisomerase II inhibitor. Physiologically, DJ34 induced apoptosis, cell cycle arrest and cell differentiation. Taken together, we have identified a novel compound that dually targets c-Myc and p53 in a wide variety of cancers, and with particularly strong activity against leukemic stem cells.
    Keywords:  ABL tyrosine kinase; Myc (c-Myc); anticancer drug; drug screening; leukemia; mRNA; p53; phosphoproteomics
  12. Diagnostics (Basel). 2020 Dec 04. pii: E1048. [Epub ahead of print]10(12):
      Advances in acute myeloid leukemia (AML) genomics and targeted therapies include the recently approved BCL2 inhibitor venetoclax. The association between BCL2 expression and patient outcome was analyzed in a series of 176 consecutive AML patients at diagnosis (Dx), post-induction (PI), complete remission (CR) and relapse (RL). Levels increased significantly at relapse (mean 1.07 PI/0.96 CR vs. 2.17 RL, p = 0.05/p = 0.03). In multivariate analysis, high BCL2-Dx were marginally associated with worse progression-free survival, while high PI levels or at CR had an independent negative impact on outcome (PI: HR 1.58, p = 0.014; CR: HR 1.96, p = 0.008). This behavior of high PI or CR BCL2 levels and increased risk was maintained in a homogeneous patient subgroup of age <70 and intermediate cytogenetic risk (PI: HR 2.44, p = 0.037; CR: HR 2.71, p = 0.049). Finally, for this subgroup, high BCL2 at relapse indicated worse overall survival (OS, HR 1.15, p = 0.05). In conclusion, high BCL2 levels PI or at CR had an independent negative impact on patient outcome. Therefore, BCL2 expression is a dynamic marker that may be useful during AML patient follow up, and BCL2 levels at PI and/or CR may influence response to anti-BCL2 therapy.
    Keywords:  BCL2 inhibitors; acute myeloid leukemia; biomarkers; induction therapy; molecular diagnostics; patient outcome
  13. Syst Rev. 2020 Dec 07. 9(1): 285
      BACKGROUND: FMS-like tyrosine kinase 3 (FLT3) is the most frequent mutation in AML. With two FLT3 inhibitors recently approved by the FDA (midostaurin and gilteritinib), there is a need to evaluate these targeted agents.PURPOSE: To assess the clinical effectiveness of FLT3 inhibitors in AML patients.
    METHODS: Standard systematic review methods were utilised. Searches were conducted to July 2020 for completed and in-progress randomised controlled trials of FLT3 inhibitors in AML. A fixed-effect meta-analysis was undertaken.
    RESULTS: Eight completed trials involving 2656 patients and assessing five different FLT3 inhibitors (sorafenib, lestaurtinib, midostaurin, gilteritinib and quizartinib) were included. The pooled results were as follows (FLT3 inhibitor/control): overall survival hazard ratio (HR) = 0.83 (95% confidence interval [CI] 0.75 to 0.92, p = 0.0005), event-free survival HR = 0.85 (95% CI 0.77 to 0.94, p = 0.002), relapse-free survival HR = 0.76 (95% CI 0.64 to 0.90, p = 0.001), complete remission relative risk (RR) = 1.11 (95% CI 1.00 to 1.22. p = 0.05) and 60-day mortality RR = 1.04 (95% CI 0.77 to 1.40, p = 0.79). Relative risk of grade 3 and above vascular, dermatological, respiratory and hepatobiliary adverse events were found to be statistically significantly higher in the FLT3 inhibitor group compared to control, but the actual numbers of events were relatively small. Nineteen ongoing trials are still in progress, only one of which specifically targets older patients with AML.
    CONCLUSIONS: There is evidence to support the use of FLT3 inhibitors in patients with AML, but more data is needed to verify the optimum use of the drugs regarding type of inhibitor, disease stage and patient characteristics, not only in relation to disease control, but adverse events and quality of life. There are a large number of ongoing trials; therefore, the results of this review are not a fait accompli; thus, is it recommended that the review be updated in a couple of years' time. Given the challenges in extracting the complete data set required to assess clinical effectiveness, it is highly recommended that ongoing and future trials improve transparency and consistency of reporting of all trial outcomes, particularly disease control and adverse events, to enable a global clinical effectiveness assessment.
    Keywords:  AML; Adverse events; FLT3 inhibitors; Gilteritinib; Meta-analysis; Midostaurin; Quizartinib; Sorafenib; Survival; Systematic review
  14. Blood Adv. 2020 Dec 08. 4(23): 6077-6085
      Machine learning (ML) is rapidly emerging in several fields of cancer research. ML algorithms can deal with vast amounts of medical data and provide a better understanding of malignant disease. Its ability to process information from different diagnostic modalities and functions to predict prognosis and suggest therapeutic strategies indicates that ML is a promising tool for the future management of hematologic malignancies; acute myeloid leukemia (AML) is a model disease of various recent studies. An integration of these ML techniques into various applications in AML management can assure fast and accurate diagnosis as well as precise risk stratification and optimal therapy. Nevertheless, these techniques come with various pitfalls and need a strict regulatory framework to ensure safe use of ML. This comprehensive review highlights and discusses recent advances in ML techniques in the management of AML as a model disease of hematologic neoplasms, enabling researchers and clinicians alike to critically evaluate this upcoming, potentially practice-changing technology.
  15. Elife. 2020 Dec 07. pii: e61405. [Epub ahead of print]9
      Mutations in genes encoding subunits of the cohesin complex are common in several cancers, but may also expose druggable vulnerabilities. We generated isogenic MCF10A cell lines with deletion mutations of genes encoding cohesin subunits SMC3, RAD21 and STAG2 and screened for synthetic lethality with 3,009 FDA-approved compounds. The screen identified several compounds that interfere with transcription, DNA damage repair and the cell cycle. Unexpectedly, one of the top 'hits' was a GSK3 inhibitor, an agonist of Wnt signaling. We show that sensitivity to GSK3 inhibition is likely due to stabilization of b-catenin in cohesin mutant cells, and that Wnt-responsive gene expression is highly sensitized in STAG2-mutant CMK leukemia cells. Moreover, Wnt activity is enhanced in zebrafish mutant for cohesin subunits stag2b and rad21. Our results suggest that cohesin mutations could progress oncogenesis by enhancing Wnt signaling, and that targeting the Wnt pathway may represent a novel therapeutic strategy for cohesin mutant cancers.
    Keywords:  cancer biology; chromosomes; gene expression; human; zebrafish
  16. Leuk Lymphoma. 2020 Dec 07. 1-14
      Tyrosine kinase inhibitors (TKIs) are teratogenic. Chronic myeloid leukemia (CML) is increasingly identified in younger patients who wish to conceive, the management of CML during pregnancy is challenging. We reviewed 51 pregnancies involving 37 patients (30 women, 10 with >1 pregnancy and 7 men) who were either diagnosed with CML during pregnancy or receiving TKI at the time of conception. Ten women were involved in >1 pregnancies. Fifteen women were diagnosed with CML during pregnancy: 10 were treated with hydroxyurea (n = 5), interferon-alfa (n = 3), leukapheresis (n = 1), or nilotinib (n = 1). There were 14 (82%) healthy babies born on term including 2 sets of twins, 2 spontaneous miscarriages (12%), and 1 elective abortion (6%). Within 1 month of delivery or abortion, all women started TKI and achieved MR4.5 (n = 6) and MMR (n = 8) within 3-48 months. One patient, treated with interferon during pregnancy, died of blast phase within 2 months. Four of the 14 remaining women later conceived 5 other pregnancies while on TKI (3 unplanned, 2 planned). Twenty-six patients (7 men; 19 women) conceived while on TKI, with a total of 36 pregnancies. Fifteen women had 20 unplanned pregnancies while receiving TKI and discontinued immediately upon recognition of pregnancy. The median time of TKI exposure was 3 weeks (range, 2-11). Five pregnancies ended in miscarriages and 3 in elective abortion. All 7 men fathered 7 full-term healthy babies. Of 20 babies born to men and women (including one set of twins), 1 had minor abnormality. Seven women lost their responses during pregnancy but at the end of pregnancy all but 2 resumed TKI and regained responses. Seven women involved in 9 planned pregnancies discontinued TKI prior to conception for a median of 4 months (range, 1-20); 3 lost responses during pregnancy. Only 5 patients resumed therapy after delivery. Outcomes were 6 full-term healthy babies, one premature, and two miscarriages. Conception among CML patients while on TKI could be uncomplicated. While patients may lose response following treatment interruption, nearly all regain response upon resuming therapy. Therapy during pregnancy is rarely needed.
    Keywords:  CML; TKI; malformation; pregnancy; spontaneous abortion