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Background: Acute promyelocytic leukemia (APL) is the sub-type of Acute myeloid leukemia (AML) which is described by differentiation block at promyelocytic stage and t(15; 17) translocation with All trans retinoic acid (ATRA) and arsenic trioxide (ATO) as standard treatments. Chronic myeloid leukemia (CML) translocation t (19; 22) causes a rise in granulocytes and their immature precursors in the blood. Different mutations cause resistance to first-line tyrosine kinase therapies in CML. Beside drug resistance, leukemia stem cells (LSC) are critical resources for relapse and resistance in APL and CML. The drug toxicity and resistant profile associated with LSC and current therapeutics of APL and CML necessitate the development of new therapies. Imidazoles are heterocyclic nitrogen compounds with diverse cellular actions. The purpose of this research was to assess the anti-leukemic properties of four novel imidazole derivatives including L-4, L-7, R-35, and R-NIM04., Methods and Results: Pharmacological and biochemical approaches were used which showed that all four imidazole derivatives interfere with the NB4 cells proliferation, an APL cell line, while only L-7 exhibit anti-proliferative activity against K562 cells, a CML cell line. The anti-proliferative effect of imidazole derivatives was linked to apoptosis induction. Further real-time polymerase chain reaction (RT-PCR) analysis revealed downregulation of AXL-Receptor Tyrosine Kinase (AXL-RTK) and target genes of Wnt/beta-catenin pathway like c-Myc, Axin2 and EYA3. An additive effect was observed after combinatorial treatment of L-7 with standard drugs ATRA or Imatinib on the proliferation of NB4 and K562 cells respectively which was related to further downregulation of target genes of Wnt/beta catenin pathway., Conclusion: Imidazole derivatives significantly reduce proliferation of NB4 and K562 cells by inducing apoptosis, down regulating of AXL-RTK and Wnt/β-catenin target genes., (© 2024. The Author(s).)

Differentiation therapy has proven to be a success story for patients with acute promyelocytic leukemia. However, the remaining subtypes of acute myeloid leukemia (AML) are treated with cytotoxic chemotherapies that have limited efficacy and a high likelihood of resistance. As differentiation arrest is a hallmark of AML, there is increased interest in developing differentiation-inducing agents to enhance disease-free survival. Here, we provide a comprehensive review of current reports and future avenues of nucleic acid therapeutics for AML, focusing on the use of targeted nucleic acid drugs to promote differentiation. Specifically, we compare and discuss the precision of small interfering RNA, small activating RNA, antisense oligonucleotides, and aptamers to modulate gene expression patterns that drive leukemic cell differentiation. We delve into preclinical and clinical studies that demonstrate the efficacy of nucleic acid-based differentiation therapies to induce leukemic cell maturation and reduce disease burden. By directly influencing the expression of key genes involved in myeloid maturation, nucleic acid therapeutics hold the potential to induce the differentiation of leukemic cells towards a more mature and less aggressive phenotype. Furthermore, we discuss the most critical challenges associated with developing nucleic acid therapeutics for myeloid malignancies. By introducing the progress in the field and identifying future opportunities, we aim to highlight the power of nucleic acid therapeutics in reshaping the landscape of myeloid leukemia treatment., (© 2024. The Author(s).)

Objective: To investigate the role of ginsenoside Rd (GRd) in acute myeloid leukemia (AML) cell differentiation., Methods: AML cells were treated with GRd (25, 50, 100 and 200 µg/mL), retinoic acid (RA, 0.1g/L) and PD98059 (20 mg/mL) for 72 h, cell survival was detected by methylthiazolyldiphenyl-tetrazolium bromide and colony formation assays, and cell cycle was detected by flow cytometry. Cell morphology and differentiation were observed by Wright-Giemsa staining, peroxidase chemical staining and cellular immunochemistry assay, respectively. The protein expression levels of GATA binding protein 1 (GATA-1), purine rich Box-1 (PU.1), phosphorylated-extracellular signal-related kinase (p-ERK), ERK, phosphorylated-glycogen synthase kinase-3β (p-GSK3β), GSK3β and signal transducer and activator of transcription 1 (STAT1) were detected by Western blot. Thirty-six mice were randomly divided into 3 groups using a random number table: model control group (non-treated), GRd group [treated with 200 mg/(kg·d) GRd] and homoharringtonine (HTT) group [treated with 1 mg/(kg·d) HTT]. A tumor-bearing nude mouse model was established, and tumor weight and volume were recorded. Changes of subcutaneous tumor tissue were observed after hematoxylin and eosin staining. WT1 and GATA-1 expressions were detected by immunohistochemical staining., Results: The cell survival was inhibited by GRd in a dose-dependent manner and GRd caused G0/G1 cell arrest (p<0.05). GRd treatment induced leukemia cell differentiation, showing increased expressions of peroxidase and specific proteins concerning erythrogenic or granulocytic differentiation (p<0.05). GRd treatment elicited upregulation of p-ERK, p-GSK-3β and STAT1 expressions in cells, and reversed the effects of PD98059 on inhibiting the expressions of peroxidase, GATA-1 and PU.1 (P<0.05). After GRd treatment, tumor weight and volume of mice were decreased, and tumor cells underwent massive apoptosis and necrosis (P<0.05). WT1 level was decreased, and GATA-1 level was significantly increased in subcutaneous tumor tissues (P<0.05 or P<0.01)., Conclusion: GRd might induce the differentiation of AML cells via regulating the ERK/GSK-3β signaling pathway., (© 2023. The Chinese Journal of Integrated Traditional and Western Medicine Press and Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose of Review: This review meticulously delves into existing literature and recent findings to elucidate the intricate link between obesity and clonal hematopoiesis of indeterminate potential (CHIP) associated clonal hematopoiesis. It aims to enhance our comprehension of this multifaceted association, offering insights into potential avenues for future research and therapeutic interventions., Recent Findings: Recent insights reveal that mutations in CHIP-associated genes are not limited to symptomatic patients but are also present in asymptomatic individuals. This section focuses on the impact of obesity-induced inflammation and fatty bone marrow (FBM) on the development of CHIP-associated diseases. Common comorbidities such as obesity, diabetes, and infection, fostering pro-inflammatory environments, play a pivotal role in the acceleration of these pathologies. Our research underscores a notable association between CHIP and an increased waist-to-hip ratio (WHR), emphasizing the link between obesity and myeloid leukemia. Recent studies highlight a strong correlation between obesity and myeloid leukemias in both children and adults, with increased risks and poorer survival outcomes in overweight individuals., Summary: We discuss recent insights into how CHIP-associated pathologies respond to obesity-induced inflammation, offering implications for future studies in the intricate field of clonal hematopoiesis., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Macrophages are fundamental cells of the innate immune system that support normal haematopoiesis and play roles in both anti-cancer immunity and tumour progression. Here we use a chimeric mouse model of chronic myeloid leukaemia (CML) and human bone marrow (BM) derived macrophages to study the impact of the dysregulated BM microenvironment on bystander macrophages. Utilising single-cell RNA sequencing (scRNA-seq) of Philadelphia chromosome (Ph) negative macrophages we reveal unique subpopulations of immature macrophages residing in the CML BM microenvironment. CML exposed macrophages separate from their normal counterparts by reduced expression of the surface marker CD36, which significantly reduces clearance of apoptotic cells. We uncover aberrant production of CML-secreted factors, including the immune modulatory protein lactotransferrin (LTF), that suppresses efferocytosis, phagocytosis, and CD36 surface expression in BM macrophages, indicating that the elevated secretion of LTF is, at least partially responsible for the supressed clearance function of Ph- macrophages., (© 2024. The Author(s).)

Transient abnormal myelopoiesis (TAM) is a Down syndrome-related pre-leukaemic condition characterized by somatic mutations in the haematopoietic transcription factor GATA-1 that result in exclusive production of its shorter isoform (GATA-1 S ). Given the common hallmark of altered miRNA expression profiles in haematological malignancies and the pro-leukaemic role of GATA-1 S , we aimed to search for miRNAs potentially able to modulate the expression of GATA-1 isoforms. Starting from an in silico prediction of miRNA binding sites in the GATA-1 transcript, miR-1202 came into our sight as potential regulator of GATA-1 expression. Expression studies in K562 cells revealed that miR-1202 directly targets GATA-1, negatively regulates its expression, impairs GATA-1 S production, reduces cell proliferation, and increases apoptosis sensitivity. Furthermore, data from TAM and myeloid leukaemia patients provided substantial support to our study by showing that miR-1202 down-modulation is accompanied by increased GATA-1 levels, with more marked effects on GATA-1 S . These findings indicate that miR-1202 acts as an anti-oncomiR in myeloid cells and may impact leukaemogenesis at least in part by down-modulating GATA-1 S levels.

Reactive oxygen species (ROS) work as a second messenger, modulating cell response and establishing homeostasis. Abrupt changes in ROS are used to modulate transient cell response to different stimuli, from viral infection to inflammation. Chronic exposure to high ROS concentration can cause cellular damage and promote the development of diseases. Leukemogenesis is adapted to high concentrations of ROS, hijacking the ROS system, and uses kinase cascades to promote survival advantages. The oxidation-reduction (redox) machinery is composed of enzymes that orchestrate all classes of protein and use available Cys as transmitters and sensors, to disseminate stress signals through cells via kinase cascades. Myeloid leukemias (MLs) are known for being a heterogeneous disease, and clonal diversity is remarkably characterized by differences in the activation of kinase-regulated signaling cascades to provide survival advantage. Stress-activated kinase cascades and other cascades are regulated by the ROS system. Several studies present nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) and the ER-resident NOX4 as key elements of ROS activity in healthy myeloid cells and myeloid leukemia. Targeting ROS presents an attractive therapeutic strategy for (MLs) patients, but the boundaries between pro-apoptotic and anti-apoptotic ROS concentrations are not well established. Detailed understanding of the signaling switches that determine cell fate needs to be well understood. This work explores several aspects of the redox system and thiol-mediated reactions with focus on kinase signaling in myeloid cancers and highlights some of the challenges., (Copyright © 2024. Published by Elsevier Inc.)

Competing Interests: The authors declare that they have no conflict of interest.

Contemporary data on infections after intensive chemotherapy for acute myeloid leukemia (AML) are scarce. Cladribine, high-dose cytarabine, G-CSF, and dose-escalated mitoxantrone ("CLAG-M") may result in higher remission rates than standard-dose cytarabine plus anthracycline ("7 + 3") but may result in more infections. We compared moderate to severe infections occurring up to 90 days after the first induction cycle for AML or other high-grade myeloid neoplasms in patients receiving CLAG-M for newly diagnosed (n = 196) or relapsed/refractory disease (n = 131) or 7 + 3 for newly diagnosed disease (n = 115). For newly diagnosed disease, microbiologically documented infections were more frequent after CLAG-M compared to 7 + 3 (adjusted rate ratio, 1.65 [95% CI, 1.06-2.58]; P = 0.03), with a cumulative incidence of 27.8% and 16.5% by day 90, respectively. Patients receiving CLAG-M for relapsed/refractory disease had the highest cumulative incidence of 50.7%. Bacterial bloodstream infections were the most frequent followed by respiratory tract infections. Among 29 patients (7%) who died, infection was a primary or contributing cause of death in 59%. These data indicate that infections continue to cause substantial morbidity in patients treated for AML, especially those treated for relapsed/refractory disease, and are more common with newer, more myelosuppressive regimens such as CLAG-M. Improved strategies for infection prevention are needed., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Angiogenesis and factors affecting it are one of the most critical elements in vascular proliferation. Although they are essential in generating new vessels, their potential to generate solid tumors is accepted as a pathological condition. Leukemia can be an appropriate example of this condition., Aim: This study aims to evaluate the Tie/angiopoietin system effect in Leukemia., Methods: Leukemia is a pathological condition in which the uncontrolled proliferation of abnormal cells occurs in the bone marrow or lymphatic system., Results: Based on severity and speed of development, many different types of Leukemia have been discovered through years of studying. Acute lymphocytic Leukemia (ALL), acute myeloid Leukemia (AML), chronic lymphocytic Leukemia (CLL), and chronic myeloid Leukemia (CML) are the four main types of Leukemia., Conclusion: Leukemia's function, effects, and medication have been a great concern over the years. Angiogenic factors such as angiopoietin-1 (Ang1), angiopoietin-2 (Ang2), angiopoietin-4 (Ang4), a combination of them and their receptors and their effect on Leukemia are the main purposes discussed in this article., Competing Interests: Conflict of Interest Authors don’t have any interest., (Copyright © 2023 Elsevier GmbH. All rights reserved.)

Background/aim: TYRO3 is a member of the TAM family (TYRO3, AXL, and MERTK) of receptor tyrosine kinases. While the roles of activated AXL and MERTK in the growth of leukaemia cells have been reported, the effect of TYRO3 has not been determined. Therefore, we examined the effects of TYRO3 knockdown on the growth of leukaemia cell lines., Materials and Methods: Three human leukaemia cell lines (AA derived from pure erythroid leukaemia, OCI/AML2, and K562), which express TYRO3 protein were used in this study. To induce TYRO3 knockdown, small interfering RNA (siRNA) against TYRO3 was transfected using an electroporation system. Cell growth was assessed by a colorimetric assay. The expression levels and activation of various signalling proteins were examined by immunoblotting. Changes in comprehensive gene expression after TYRO3 knockdown were examined by microarray analysis., Results: TYRO3 knockdown suppressed cell growth in the leukaemia cell lines tested. Additionally, the knockdown suppressed phosphorylation of signal transducer and activator of transcription-3 in AA cells, and extracellular signal-regulated kinase (ERK) 1/2 in AA and OCI/AML2 cells; both are downstream molecules of TYRO3 signalling. TYRO3 knockdown also suppressed the expression of survivin in all the cell lines. TYRO3 knockdown potently suppressed TYRO3 mRNA expression but not that of AXL and MERTK. Furthermore, TYRO3 knockdown suppressed cyclin D1 mRNA expression, which is a downstream molecule of ERK., Conclusion: TYRO3 plays a role in leukaemia cell growth and is a potential therapeutic target for leukaemia., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background/aim: Azoxystrobin (AZOX), a methoxyacrylate derivative, has potent antimicrobial and antitumor activities. Here, we report the anticancer effects of AZOX on the p53-negative human myelogenous leukemia cell line HL-60RG and the p53 positive human T-cell leukemia cell line MOLT-4F., Materials and Methods: Using both leukemia cells, the anticancer effect of AZOX treatment was analyzed throughout the cell cycle., Results: AZOX damaged both cell lines dose-dependently, and the cell damage rates were almost the same in both lines. Cell cycle distribution analysis showed that the treated MOLT-4F cells arrested at the S phase, whereas HL-60RG cells increased during the subG1 phase, suggesting that cell death was occurring. AZOX-induced cell death in HL-60RG was inhibited with the addition of uridine, which is used as a substrate for the salvage pathway of pyrimidine nucleotides., Conclusion: AZOX has p53-independent anticancer effects in leukemia cells, but the mechanisms underlying the damage differ between cell lines., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

MECOM rearrangements are recurrent in myeloid neoplasms and associated with poor prognosis. However, only inv(3)(q21q26.2) and t(3;3)(q21;q26.2), the classic MECOM rearrangements resulting in RPN1-MECOM rearrangement with Mecom overexpression and GATA2 haploinsufficiency, define the distinct subtype of acute myeloid leukemia (AML), and serve as presumptive evidence for myelodysplastic syndrome based on the current World Health Organization classification. Myeloid neoplasms with nonclassic 3q26.2/MECOM rearrangements have been found to be clinically aggressive, but comparative analysis of clinicopathologic and genomic features is limited. We retrospectively studied cohorts of myeloid neoplasms with classic and nonclassic MECOM rearrangements. Cases with classic rearrangements consisted predominantly of AML, often with inv(3) or t(3;3) as the sole chromosome abnormality, whereas the group of nonclassic rearrangements included a variety of myeloid neoplasms, often with complex karyotype without TP53 mutations and similarly dismal overall survival. Immunohistochemistry revealed Mecom protein overexpression in both groups, but overexpression in cases with nonclassic rearrangements was mediated through a mechanism other than GATA2 distal enhancer involvement typical for classic rearrangement. Our results demonstrated that myeloid neoplasms with nonclassic 3q26.2/MECOM rearrangements encompass a diverse group of diseases with poor clinical outcome, overexpression of Mecom protein as a result of the nonclassic mechanism of MECOM activation., (© 2021 Wiley Periodicals LLC.)

Background: Older patients encompass about 75 % of patients with acute myeloid leukemia (AML). Today therapeutic options to prevent relapse in older patients who managed to achieve complete remission (CR) after intensive chemotherapy are scarce. Recent randomized controlled trials (RCTs) have aimed to reduce the risk of relapse by means of post-CR maintenance therapy., Methods: We performed a systematic review and meta-analysis of RCTs comparing the efficacy and safety of maintenance with hypomethylating agents (HMA) vs. observation, conventional care or placebo in older patients with AML who are not candidates for allogeneic hematopoietic transplantation (allo-HCT). We searched Cochrane Library, PubMed and conference proceedings up to August 2021., Results: Six trials were included. Treatment with hypomethylating agents significantly improved overall survival (HR 0.80, 95 % CI 0.70 to 0.91, I 2 = 30 %), and disease control (HR 0.80, 95 % CI 0.70 to 0.91, I 2 = 0). A significant decrease was seen in both one year mortality (Risk Ratio [RR] 0.61, 95 % CI 0.48 to 0.77, I 2 = 0) and mortality at the end of follow-up (RR 0.77, 95 % CI 0.67 to 0.88, I 2 = 0). The rate of relapse at 6 months and at one-two years was lower in the HMA arm vs. control (RR, 0.59; 95 % CI, 0.47-0.72; RR, 0.74, I 2 = 0; 95 % CI 0.69 - 0.91, I 2 = 41 %, respectively). HMA were associated with a statistically non-significant increase in the risk of serious adverse events (RR 3.44, 95 % CI 0.93-12.74, I 2 = 80 %)., Conclusions: Our meta-analysis shows that in older patients who are not candidates for allo-HCT, maintenance therapy with HMA improves OS and disease control without a statistically significant increase in adverse events., (Copyright © 2021. Published by Elsevier Ltd.)

Mixed-phenotype acute leukemia is a rare subtype of leukemia in which both myeloid and lymphoid markers are co-expressed on the same malignant cells. The pathogenesis is largely unknown, and the treatment is challenging. We previously reported the specific association of the recurrent t(8;12)(q13;p13) chromosomal translocation that creates the ETV6-NCOA2 fusion with T/myeloid leukemias. Here we report that ETV6-NCOA2 initiates T/myeloid leukemia in preclinical models; ectopic expression of ETV6-NCOA2 in mouse bone marrow hematopoietic progenitors induced T/myeloid lymphoma accompanied by spontaneous Notch1-activating mutations. Similarly, cotransduction of human cord blood CD34+ progenitors with ETV6-NCOA2 and a nontransforming NOTCH1 mutant induced T/myeloid leukemia in immunodeficient mice; the immunophenotype and gene expression pattern were similar to those of patient-derived ETV6-NCOA2 leukemias. Mechanistically, we show that ETV6-NCOA2 forms a transcriptional complex with ETV6 and the histone acetyltransferase p300, leading to derepression of ETV6 target genes. The expression of ETV6-NCOA2 in human and mouse nonthymic hematopoietic progenitor cells induces transcriptional dysregulation, which activates a lymphoid program while failing to repress the expression of myeloid genes such as CSF1 and MEF2C. The ETV6-NCOA2 induced arrest at an early immature T-cell developmental stage. The additional acquisition of activating NOTCH1 mutations transforms the early immature ETV6-NCOA2 cells into T/myeloid leukemias. Here, we describe the first preclinical model to depict the initiation of T/myeloid leukemia by a specific somatic genetic aberration., (© 2022 by The American Society of Hematology.)

Technological advances have made it possible to offer home-based chemotherapy to patients without health care professionals being present. Prior studies on effects of home-based treatment lack inclusion of patients with hematologic malignancies. We present data from a multicenter single-arm feasibility and safety study of home-based intensive chemotherapy in patients with newly diagnosed acute myeloid leukemia and their quality of life and psychological wellbeing. This national study included patients from six sites in Denmark who received intensive chemotherapy on programmed CADD Solis infusion pumps through a central venous catheter and were also managed as outpatients during treatment-induced pancytopenia. Data are presented from 104 patients, receiving 272 treatments with 1.096 (mean 4.57, SD 3.0) home infusion days out of 1.644 treatment days (67 %). Sixty-two of 168 (36.9 %) reinduction and consolidation treatment cycles ensuing pancytopenia phases were solely handled in the outpatient clinic. Patients reported high satisfaction with home-based treatment, which had a positive influence on their ability to be involved in their treatment and be socially and physically active. No unexpected events occurred during the intervention. Overall, patients improved in all quality of life outcomes over time. Home-based intensive chemotherapy treatment was feasible and safe in this population. ClinicalTrials.gov identifier: NCT04904211., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

A decreased percentage of CD177 pos neutrophils is frequently present in MDS and AML and is a useful flow cytometry (FCM) marker for the identification of MDS. The underlying mechanism leading to the low percentage of CD177 pos neutrophils in MDS has not been explained. The aim of this study was to identify whether specific somatic mutations in myeloid neoplasms are associated with the low percentage of CD177 pos neutrophils. 507 myeloid neoplasms with one or more pathogenic molecular abnormality identified by NGS and in which CD177 expression was assessed were evaluated. Correlation with CD177 expression was determined for 39 variables (including genes mutated, diagnostic groups and gender) using a 40 % cutoff level for low CD177 expression. In multivariate analysis mutations involving NPM1 (OD 0.26), RUNX1 (OD 0.39), TET2 (OD 0.58), and U2AF1 S34F (OD 0.25) were associated with low percentage of CD177 pos neutrophils when all cases were evaluated. JAK2 (OD 2.5) alteration was associated with increased percentage of CD177 pos neutrophils. Differences were noted between diagnostic subgroups with no single mutation associated with decreased CD177 pos neutrophils in MDS and CCUS. The findings demonstrate an association between the percentage of CD177 pos neutrophils and somatically acquired mutations involving several genes., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Acute Myeloid Leukemia (AML) represents 1 % of all new cancer diagnosis made annually in the US and has a five-year survival of 30 %. Traditional treatment includes aggressive induction therapy followed by consolidation therapy that may include a hematopoietic stem cell transplant (HSCT). Thus far, HSCT remains the only potentially curative therapy for many patients with AML owing to the graft-versus-leukemia effect elicited by this treatment. The use of novel therapies, specifically immunotherapy, in the treatment of AML has been limited by the lack of appropriate target antigens, therapy associated toxicities and variable success with treatment. Antigenic variability on leukemia cells and the sharing of antigens by malignant and non-malignant cells makes the identification of appropriate antigens problematic. While studies with immunotherapeutic agents are underway, prior investigations have demonstrated a mixed response with some studies prematurely discontinued due to associated toxicities. This review presents a discussion of the envisioned role of immunotherapy in the treatment of AML in the setting of mixed therapeutic success and potentially lethal toxicities., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Interrogation of cellular metabolism with high-throughput screening approaches can unravel contextual biology and identify cancer-specific metabolic vulnerabilities. To systematically study the consequences of distinct metabolic perturbations, we assemble a comprehensive metabolic drug library (CeMM Library of Metabolic Drugs; CLIMET) covering 243 compounds. We, next, characterize it phenotypically in a diverse panel of myeloid leukemia cell lines and primary patient cells. Analysis of the drug response profiles reveals that 77 drugs affect cell viability, with the top effective compounds targeting nucleic acid synthesis, oxidative stress, and the PI3K/mTOR pathway. Clustering of individual drug response profiles stratifies the cell lines into five functional groups, which link to specific molecular and metabolic features. Mechanistic characterization of selective responses to the PI3K inhibitor pictilisib, the fatty acid synthase inhibitor GSK2194069, and the SLC16A1 inhibitor AZD3965, bring forth biomarkers of drug response. Phenotypic screening using CLIMET represents a valuable tool to probe cellular metabolism and identify metabolic dependencies at large., (© 2021. The Author(s).)

Children with Down syndrome are at an elevated risk of leukemia, especially myeloid leukemia (ML-DS). This malignancy is frequently preceded by transient abnormal myelopoiesis (TAM), which is self-limited expansion of fetal liver-derived megakaryocyte progenitors. An array of international studies has led to consensus in treating ML-DS with reduced-intensity chemotherapy, leading to excellent outcomes. In addition, studies performed in the past 20 years have revealed many of the genetic and epigenetic features of the tumors, including GATA1 mutations that are arguably associated with all cases of both TAM and ML-DS. Despite these advances in understanding the clinical and biological aspects of ML-DS, little is known about the mechanisms of relapse. Upon relapse, patients face a poor outcome, and there is no consensus on treatment. Future studies need to be focused on this challenging aspect of leukemia in children with DS., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Despite the great advance in treatment, cytogenetically normal Acute myeloid leukemia (CN-AML) is still a challenging entity. The discovery of IDH1 mutation in AML together with the frequent co-mutations; NPM1 and FLT3-ITD throughs a new insight into the pathogenesis and outcome of CN-AML. Recently, there has been an increasing number of recurring mutations in other genes for which the forecasting effect is still required. Despite the large number of risk variables established, there are relatively few prognostic indicators that can help in treatment decisions in AML patients. This study aimed at recording the frequency of IDH1 and NPM1 mutations in newly diagnosed AML and, dual clinicopathological significance. IDH1 and NPM1 mutations were analyzed using High-Resolution Melting curve analysis PCR in 78 newly diagnosed AML patients; 30 pediatric and 48 adult AML patients. IDH1 mutation was detected in 6 out of the 48 adult AML cases (12.5%) and all of them had intermediate cytogenetic prognostic stratification. 5/6 mutant IDH1 patients showed NPM1 co-mutation (P-value= 0.008). Mutant IDH1 patients showed significant resistance to induction therapy (P-value <0.001) and even those who achieved complete remission were relapsed later. Within the intermediate cytogenetic group, the IDH1 mutated patients had short overall survival (HR 12.9, 95% CI (3.1- 53.45) and event-free survival (HR 15.7, 95% CI (2.99-82.72) and P-value <0.001). IDH1 mutation is closely linked to the intermediate cytogenetic stratified group and in particular old age patients and has a great impact on their survival.

Successful treatment of acute myeloid leukemia (AML) with chimeric antigen receptor (CAR) T cells is hampered by toxicity on normal hematopoietic progenitor cells and low CAR T cell persistence. Here, we develop third-generation anti-CD123 CAR T cells with a humanized CSL362-based ScFv and a CD28-OX40-CD3ζ intracellular signaling domain. This CAR demonstrates anti-AML activity without affecting the healthy hematopoietic system, or causing epithelial tissue damage in a xenograft model. CD123 expression on leukemia cells increases upon 5'-Azacitidine (AZA) treatment. AZA treatment of leukemia-bearing mice causes an increase in CTLA-4 negative anti-CD123 CAR T cell numbers following infusion. Functionally, the CTLA-4 negative anti-CD123 CAR T cells exhibit superior cytotoxicity against AML cells, accompanied by higher TNFα production and enhanced downstream phosphorylation of key T cell activation molecules. Our findings indicate that AZA increases the immunogenicity of AML cells, enhancing recognition and elimination of malignant cells by highly efficient CTLA-4 negative anti-CD123 CAR T cells., (© 2021. The Author(s).)

Mechanical stiffness is closely related to cell adhesion and rounding in some cells. In leukocytes, dephosphorylation of ezrin/radixin/moesin (ERM) proteins is linked to cell adhesion events. To elucidate the relationship between surface stiffness, cell adhesion, and ERM dephosphorylation in leukocytes, we examined the relationship in the myelogenous leukemia line, KG-1, by treatment with modulation drugs. KG-1 cells have ring-shaped cortical actin with microvilli as the only F-actin cytoskeleton, and the actin structure constructs the mechanical stiffness of the cells. Phorbol 12-myristate 13-acetate and staurosporine, which induced cell adhesion to fibronectin surface and ERM dephosphorylation, caused a decrease in surface stiffness in KG-1 cells. Calyculin A, which inhibited ERM dephosphorylation and had no effect on cell adhesion, did not affect surface stiffness. To clarify whether decreasing cell surface stiffness and inducing cell adhesion are equivalent, we examined KG-1 cell adhesion by treatment with actin-attenuated cell softening reagents. Cytochalasin D clearly diminished cell adhesion, and high concentrations of Y27632 slightly induced cell adhesion. Only Y27632 slightly decreased ERM phosphorylation in KG-1 cells. Thus, decreasing cell surface stiffness and inducing cell adhesion are not equivalent, but these phenomena are coordinately regulated by ERM dephosphorylation in KG-1 cells., (© 2021. Japan Human Cell Society.)

Background: Acute myeloid leukemia (AML) is a malignancy commonly seen in adults. Previous studies indicated that TRIM14 played a tumorigenic role in various types of cancer and miR-23b-5p was down-regulated in human mesenchymal stem cell-derived exosomes (HMSC-exos) of AML patients. However, their roles in AML remains unclear. Our study aims to investigate the role of TRIM14 and miR-23b-5p in the pathogenesis of AML., Materials and Methods: The blood specimen was collected from de novo AML patients and healthy donators. Exosomes were extracted from the culture medium of human mesenchymal stem cells under ultracentrifugation. Then exosomes were co-cultured with AML cells to determine the effect of their contents. The cell proliferation was detected by cell counting kit-8 assay, whereas the cell apoptosis was detected by flow cytometry. The expression of miR-23b-5p and TRIM14 was silenced or overexpressed to explore their biological functions in AML. Luciferase reporter assay was conducted to validate the interaction between miR-23b-5p and TRIM14. Gene expression was determined by quantitative real-time PCR and immunoblots., Results: TRIM14 was significantly increased in AML patients and cell lines. The inhibition of TRIM14 significantly reduced the proliferation and induced the apoptosis of AML cells via activating PI3K/AKT pathway, whereas its overexpression exhibited reversed effects. HMSC-exos could suppress the proliferation of AML cells through the delivery of miR-23b-5p. Moreover, miR-23b-5p inhibited the transcription of TRIM14 by binding on its 3'UTR region. Overexpression of TRIM14 exhibited reversed effect against the function of miR-23b-5p mimic., Conclusion: TRIM14 could promote the proliferation of AML cells via activating PI3K/AKT pathway, which was reversed by HMSC-exos through delivering miR-23b-5p. These findings indicated that miR-23b-5p and TRIM14 could be applied as potential targets for the treatment of AML., (© 2021. The Author(s).)

Recent genome-wide studies have revealed that aging or chronic inflammation can cause clonal expansion of cells in normal tissues. Clonal hematopoiesis has been the most intensively studied form of clonal expansion in the last decade. Clonal hematopoiesis of indeterminate potential (CHIP) is an age-related phenomenon observed in elderly individuals with no history of hematological malignancy. The most frequently mutated genes in CHIP are DNMT3A, TET2, and ASXL1, which are associated with initiation of leukemia. Importantly, CHIP has been the focus of a number of studies because it is an independent risk factor for myeloid malignancy, cardiovascular disease (CVD), and all-cause mortality. Animal models recapitulating human CHIP revealed that CHIP-associated mutations alter the number and function of hematopoietic stem and progenitor cells (HSPCs) and promote leukemic transformation. Moreover, chronic inflammation caused by infection or aging confers a fitness advantage to the CHIP-associated mutant HSPCs. Myeloid cells, such as macrophages with a CHIP-associated mutation, accelerate chronic inflammation and are associated with increased levels of inflammatory cytokines. This positive feedback loop between CHIP and chronic inflammation promotes development of atherosclerosis and chronic heart failure and thereby increases the risk for CVD. Notably, HSPCs with a CHIP-associated mutation may alter not only innate but also acquired immune cells. This suggests that CHIP is involved in the development of solid cancers or immune disorders, such as aplastic anemia. In this review, we provide an overview of recent findings on CHIP. We also discuss potential interventions for treating CHIP and preventing myeloid transformation and CVD progression., (© 2021 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Chromosomal rearrangements are a frequent cause of oncogene deregulation in human malignancies. Overexpression of EVI1 is found in a subgroup of acute myeloid leukemia (AML) with 3q26 chromosomal rearrangements, which is often therapy resistant. In AMLs harboring a t(3;8)(q26;q24), we observed the translocation of a MYC super-enhancer (MYC SE) to the EVI1 locus. We generated an in vitro model mimicking a patient-based t(3;8)(q26;q24) using CRISPR-Cas9 technology and demonstrated hyperactivation of EVI1 by the hijacked MYC SE. This MYC SE contains multiple enhancer modules, of which only one recruits transcription factors active in early hematopoiesis. This enhancer module is critical for EVI1 overexpression as well as enhancer-promoter interaction. Multiple CTCF binding regions in the MYC SE facilitate this enhancer-promoter interaction, which also involves a CTCF binding site upstream of the EVI1 promoter. We hypothesize that this CTCF site acts as an enhancer-docking site in t(3;8) AML. Genomic analyses of other 3q26-rearranged AML patient cells point to a common mechanism by which EVI1 uses this docking site to hijack enhancers active in early hematopoiesis., (© 2021. The Author(s).)

Cohesin is a multisubunit protein complex that forms a ring-like structure around DNA. It is essential for sister chromatid cohesion, chromatin organization, transcriptional regulation, and DNA damage repair and plays a major role in dynamically shaping the genome architecture and maintaining DNA integrity. The core complex subunits STAG2, RAD21, SMC1, and SMC3, as well as its modulators PDS5A/B, WAPL, and NIPBL, have been found to be recurrently mutated in hematologic and solid malignancies. These mutations are found across the full spectrum of myeloid neoplasia, including pediatric Down syndrome-associated acute megakaryoblastic leukemia, myelodysplastic syndromes, chronic myelomonocytic leukemia, and de novo and secondary acute myeloid leukemias. The mechanisms by which cohesin mutations act as drivers of clonal expansion and disease progression are still poorly understood. Recent studies have described the impact of cohesin alterations on self-renewal and differentiation of hematopoietic stem and progenitor cells, which are associated with changes in chromatin and epigenetic state directing lineage commitment, as well as genomic integrity. Herein, we review the role of the cohesin complex in healthy and malignant hematopoiesis. We discuss clinical implications of cohesin mutations in myeloid malignancies and discuss opportunities for therapeutic targeting., (© 2021 by The American Society of Hematology.)

Age-related clonal hematopoiesis (ARCH) is characterized by age-associated accumulation of somatic mutations in hematopoietic stem cells (HSCs) or their pluripotent descendants. HSCs harboring driver mutations will be positively selected and cells carrying these mutations will rise in frequency. While ARCH is a known risk factor for blood malignancies, such as Acute Myeloid Leukemia (AML), why some people who harbor ARCH driver mutations do not progress to AML remains unclear. Here, we model the interaction of positive and negative selection in deeply sequenced blood samples from individuals who subsequently progressed to AML, compared to healthy controls, using deep learning and population genetics. Our modeling allows us to discriminate amongst evolutionary classes with high accuracy and captures signatures of purifying selection in most individuals. Purifying selection, acting on benign or mildly damaging passenger mutations, appears to play a critical role in preventing disease-predisposing clones from rising to dominance and is associated with longer disease-free survival. Through exploring a range of evolutionary models, we show how different classes of selection shape clonal dynamics and health outcomes thus enabling us to better identify individuals at a high risk of malignancy., (© 2021. The Author(s).)

Gene abnormalities, including mutations and fusions, are important determinants in the molecular diagnosis of myeloid neoplasms. The use of bone marrow (BM) smears as a source of DNA and RNA for next-generation sequencing (NGS) enables molecular diagnosis to be done with small amounts of bone marrow and is especially useful for patients without stocked cells, DNA or RNA. The present study aimed to analyze the quality of DNA and RNA derived from smear samples and the utility of NGS for diagnosing myeloid neoplasms. Targeted DNA sequencing using paired BM cells and smears yielded sequencing data of adequate quality for variant calling. The detected variants were analyzed using the bioinformatics approach to detect mutations reliably and increase sensitivity. Noise deriving from variants with extremely low variant allele frequency (VAF) was detected in smear sample data and removed by filtering. Consequently, various driver gene mutations were detected across a wide range of allele frequencies in patients with myeloid neoplasms. Moreover, targeted RNA sequencing successfully detected fusion genes using smear-derived, very low-quality RNA, even in a patient with a normal karyotype. These findings demonstrated that smear samples can be used for clinical molecular diagnosis with adequate noise-reduction methods even if the DNA and RNA quality is inferior., Competing Interests: The authors have declared that no competing interests exist.

Children with Down syndrome have a 150-fold increased risk of developing myeloid leukemia, but the mechanism of predisposition is unclear. Because Down syndrome leukemogenesis initiates during fetal development, we characterized the cellular and developmental context of preleukemic initiation and leukemic progression using gene editing in human disomic and trisomic fetal hematopoietic cells and xenotransplantation. GATA binding protein 1 ( GATA1 ) mutations caused transient preleukemia when introduced into trisomy 21 long-term hematopoietic stem cells, where a subset of chromosome 21 microRNAs affected predisposition to preleukemia. By contrast, progression to leukemia was independent of trisomy 21 and originated in various stem and progenitor cells through additional mutations in cohesin genes. CD117 + /KIT proto-oncogene (KIT) cells mediated the propagation of preleukemia and leukemia, and KIT inhibition targeted preleukemic stem cells., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Fever can provide a survival advantage during infection. Metabolic processes are sensitive to environmental conditions, but the effect of fever on T cell metabolism is not well characterized. We show that in activated CD8 + T cells, exposure to febrile temperature (39 °C) augmented metabolic activity and T cell effector functions, despite having a limited effect on proliferation or activation marker expression. Transcriptional profiling revealed an up-regulation of mitochondrial pathways, which was consistent with increased mass and metabolism observed in T cells exposed to 39 °C. Through in vitro and in vivo models, we determined that mitochondrial translation is integral to the enhanced metabolic activity and function of CD8 + T cells exposed to febrile temperature. Transiently exposing donor lymphocytes to 39 °C prior to infusion in a myeloid leukemia mouse model conferred enhanced therapeutic efficacy, raising the possibility that exposure of T cells to febrile temperatures could have clinical potential., Competing Interests: Competing interest statement: E.L.P. is a Scientific Advisory Board member of ImmunoMet Therapeutics, and E.J.P. and E.L.P. are founders of Rheos Medicines., (Copyright © 2021 the Author(s). Published by PNAS.)

Induced granulocytic differentiation of human leukemic cells under all- trans -retinoid acid (ATRA) treatment underlies differentiation therapy of acute myeloid leukemia. Knowing the regulation of this process it is possible to identify potential targets for antileukemic drugs and develop novel approaches to differentiation therapy. In this study, we have performed transcriptomic and proteomic profiling to reveal up- and down-regulated transcripts and proteins during time-course experiments. Using data on differentially expressed transcripts and proteins we have applied upstream regulator search and obtained transcriptome- and proteome-based regulatory networks of induced granulocytic differentiation that cover both up-regulated (HIC1, NFKBIA, and CASP9) and down-regulated (PARP1, VDR, and RXRA) elements. To verify the designed network we measured HIC1 and PARP1 protein abundance during granulocytic differentiation by selected reaction monitoring (SRM) using stable isotopically labeled peptide standards. We also revealed that transcription factor CEBPB and LYN kinase were involved in differentiation onset, and evaluated their protein levels by SRM technique. Obtained results indicate that the omics data reflect involvement of the DNA repair system and the MAPK kinase cascade as well as show the balance between the processes of the cell survival and apoptosis in a p53-independent manner. The differentially expressed transcripts and proteins, predicted transcriptional factors, and key molecules such as HIC1, CEBPB, LYN, and PARP1 may be considered as potential targets for differentiation therapy of acute myeloid leukemia.

There is paucity of data regarding the diagnostic yield and safety of skin biopsies in patients with acute myeloid leukemia (AML), though skin eruptions are common in these patients. We evaluated 216 patients treated in our hemato-oncology unit at a tertiary medical center between 2007 and 2018 and identified 35 patients who underwent 37 skin biopsies. The majority of biopsies were performed during induction treatment for AML (n = 26, 70%), whereas the remainder of biopsies were done prior to induction initiation (n = 8, 22%) or during consolidation chemotherapy (n = 3, 8%). Pathology findings were inconclusive in 13 cases (35%), while diagnostic biopsies were positive for drug eruptions (24%), leukemia cutis (16%), infections (11%), reactive processes (8%) and Sweet syndrome (5.5%). In almost half of cases (16/37) tissue cultures were performed. Of those, only a quarter (4/16) were positive. Histopathology and tissue culture results altered immediate patient care in 3 cases (8%), yet information obtained from biopsies had potential to affect long term patient care in 8 additional cases (21.6%). Although most skin biopsies were performed while patients had severe thrombocytopenia and neutropenia, only one patient had a complication due to the biopsy (fever and local bleeding). With the limitation of a retrospective analysis, our study suggests that skin biopsies in patients treated for AML are relatively safe. Although biopsy results infrequently alter immediate patient management, long term effect on patient care expand the potential diagnostic yield of skin biopsies.

Acute myeloid leukemia (AML) is a heterogenous hematopoietic neoplasm with various genetic abnormalities in myeloid stem cells leading to differentiation arrest and accumulation of leukemic cells in bone marrow (BM). The multiple genetic alterations identified in leukemic cells at diagnosis are the mainstay of World Health Organization classification for AML and have important prognostic implications. Recently, understanding of heterogeneous and complicated molecular abnormalities of the disease could lead to the development of novel targeted therapeutic agents. In the past years, gemtuzumab ozogamicin, BCL-2 inhibitors (venetovlax), IDH 1/2 inhibitors (ivosidenib and enasidenib) FLT3 inhibitors (midostaurin, gilteritinib, and enasidenib), and hedgehog signaling pathway inhibitors (gladegib) have received US Food and Drug Administration (FDA) approval for the treatment of AML. Especially, AML patients with elderly age and/or significant comorbidities are not currently suitable for intensive chemotherapy. Thus, novel therapeutic planning including the abovementioned target therapies could lead to improve clinical outcomes in the patients. In the review, we will present various important and frequent molecular abnormalities of AML and introduce the targeted agents of AML that received FDA approval based on the previous studies.

Ethanol has been shown to exhibit therapeutic properties as an ablative agent alone and in combination with thermal ablation. Ethanol may also increase sensitivity of cancer cells to certain physical and chemical antitumoral agents. The aim of our study was to assess the potential influence of nontoxic concentrations of ethanol on hyperthermia therapy, an antitumoral modality that is continuously growing and that can be combined with classical chemotherapy and radiotherapy to improve their efficiency. Human leukemia cells were included as a model in the study. The results indicated that ethanol augments the cytotoxicity of hyperthermia against U937 and HL60 cells. The therapeutic benefit of the hyperthermia/ethanol combination was associated with an increase in the percentage of apoptotic cells and activation of caspases-3, -8 and -9. Apoptosis triggered either by hyperthermia or hyperthermia/ethanol was almost completely abolished by a caspase-8 specific inhibitor, indicating that this caspase plays a main role in both conditions. The role of caspase-9 in hyperthermia treated cells acquired significance whether ethanol was present during hyperthermia since the alcohol enhanced Bid cleavage, translocation of Bax from cytosol to mitochondria, release of mitochondrial apoptogenic factors, and decreased of the levels of the anti-apoptotic factor myeloid cell leukemia-1 (Mcl-1). The enhancement effect of ethanol on hyperthermia-activated cell death was associated with a reduction in the expression of HSP70, a protein known to interfere in the activation of apoptosis at different stages. Collectively, our findings suggest that ethanol could be useful as an adjuvant in hyperthermia therapy for cancer.

Although the majority of patients with acute myeloid leukemia (AML) treated with intensive chemotherapy achieve a complete remission (CR), many are destined to relapse if treated with intensive chemotherapy alone. Allogeneic stem cell transplant (allo-SCT) represents a pivotally important treatment strategy in fit adults with AML because of its augmented anti-leukemic activity consequent upon dose intensification and the genesis of a potent graft-versus-leukemia effect. Increased donor availability coupled with the advent of reduced intensity conditioning (RIC) regimens has dramatically increased transplant access and consequently allo-SCT is now a key component of the treatment algorithm in both patients with AML in first CR (CR1) and advanced disease. Although transplant related mortality has fallen steadily over recent decades there has been no real progress in reducing the risk of disease relapse which remains the major cause of transplant failure and represents a major area of unmet need. A number of therapeutic approaches with the potential to reduce disease relapse, including advances in induction chemotherapy, the development of novel conditioning regimens and the emergence of the concept of post-transplant maintenance, are currently under development. Furthermore, the use of genetics and measurable residual disease technology in disease assessment has improved the identification of patients who are likely to benefit from an allo-SCT which now represents an increasingly personalized therapy. Future progress in optimizing transplant outcome will be dependent on the successful delivery by the international transplant community of randomized prospective clinical trials which permit examination of current and future transplant therapies with the same degree of rigor as is routinely adopted for non-transplant therapies., Competing Interests: CC has received honoraria from Celgene, Daichi-Sankyo, Novartis and Pfizer as well as research funding from Celgene. JL has received travel funding from Novartis and Daichi-Sankyo, honoraria from Pfizer, Janssen and Amgen. The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer CS has declared past co-authorships with one of the authors CC, to the handling editor, at the time of review., (Copyright © 2021 Loke, Buka and Craddock.)

According to the cancer stem cell (CSC) hypothesis, CSCs are the only cancer cells that can give rise to and sustain all cells that constitute a cancer as they possess inherent or acquired self-renewal potential, and their elimination is required and potentially sufficient to achieve a cure. Whilst establishing CSC identity remains challenging in most cancers, studies of low-intermediate risk myelodysplastic syndromes (MDS), other chronic myeloid malignancies and clonal haematopoiesis of indeterminant potential (CHIP) strongly support that the primary target cell usually resides in the rare haematopoietic stem cell (HSC) compartment. This probably reflects the unique self-renewal potential of HSCs in normal human haematopoiesis, combined with the somatic initiating genomic driver lesion not conferring extensive self-renewal potential to downstream progenitor cells. Mutational 'fate mapping' further supports that HSCs are the only disease-propagating cells in low-intermediate risk MDS, but that MDS-propagating potential might be extended to progenitors upon disease progression. The clinical importance of MDS stem cells has been highlighted through the demonstration of selective persistence of MDS stem cells in patients at complete remission in response to therapy. This implies that MDS stem cells might possess unique resistance mechanisms responsible for relapses following otherwise efficient treatments. Specific surveillance of MDS stem cells should be considered to assess the efficiency of therapies and as an early indicator of emerging relapses in patients in clinical remission. Moreover, further molecular characterization of purified MDS stem cells should facilitate identification and validation of improved and more stem cell-specific therapies for MDS., (© 2021 The Association for the Publication of the Journal of Internal Medicine.)

RUNX3, a transcription factor, has been implicated as a tumor suppressor in various cancers, including hematological malignancies; however, recent studies revealed an oncogenic function of RUNX3 in the pathogenesis of myeloid malignancies, such as myelodysplastic syndrome and acute myeloid leukemia. In contrast to the high frequency of mutations in the RUNX1 gene, deletion of and loss-of-function mutations in RUNX3 are rarely detected in patients with hematopoietic malignancies. Although RUNX3 is expressed in normal hematopoietic stem and progenitor cells, its expression decreases with aging in humans. The loss of Runx3 did not result in the development of lethal hematological diseases in mice despite the expansion of myeloid cells. Therefore, RUNX3 does not appear to initiate the transformation of normal hematopoietic stem cells. However, the overexpression of RUNX3 inhibits the expression and transcriptional function of the RUNX1 gene, but activates the expression of key oncogenic pathways, such as MYC, resulting in the transformation of premalignant stem cells harboring a driver genetic mutation. We herein discuss the mechanisms by which RUNX3 is activated and how RUNX3 exerts oncogenic effects on the cellular function of and transcriptional program in premalignant stem cells to drive myeloid transformation., Competing Interests: Conflict of interest disclosure The authors declare that there are no potential conflicts of interest., (Copyright © 2021 ISEH -- Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.)

Vertebrates have evolved three paralogs, termed LUC7L, LUC7L2, and LUC7L3, of the essential yeast U1 small nuclear RNA (snRNA)-associated splicing factor Luc7p. We investigated the mechanistic and regulatory functions of these putative splicing factors, of which one (LUC7L2) is mutated or deleted in myeloid neoplasms. Protein interaction data show that all three proteins bind similar core but distinct regulatory splicing factors, probably mediated through their divergent arginine-serine-rich domains, which are not present in Luc7p. Knockdown of each factor reveals mostly unique sets of significantly dysregulated alternative splicing events dependent on their binding locations, which are largely non-overlapping. Notably, knockdown of LUC7L2 alone significantly upregulates the expression of multiple spliceosomal factors and downregulates glycolysis genes, possibly contributing to disease pathogenesis. RNA binding studies reveal that LUC7L2 and LUC7L3 crosslink to weak 5' splice sites and to the 5' end of U1 snRNA, establishing an evolutionarily conserved role in 5' splice site selection., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Ecotropic viral integration site 1 (Evi1) was discovered in 1988 as a common site of ecotropic viral integration resulting in myeloid malignancies in mice. EVI1 is an oncogenic zinc-finger transcription factor whose overexpression contributes to disease progression and an aggressive phenotype, correlating with poor clinical outcome in myeloid malignancies. Despite progress in understanding the biology of EVI1 dysregulation, significant improvements in therapeutic outcome remain elusive. Here, we highlight advances in understanding EVI1 biology and discuss how this new knowledge informs development of novel therapeutic interventions. EVI1 is overexpression is correlated with poor outcome in some epithelial cancers. However, the focus of this review is the genetic lesions, biology, and current therapeutics of myeloid malignancies overexpressing EVI1.

Signal transducers and activators of transcription 5A and 5B (STAT5A and STAT5B) are two closely related STAT family members that are crucial downstream effectors of tyrosine kinase oncoproteins such as FLT3-ITD in acute myeloid leukemia (AML) and BCR-ABL in chronic myeloid leukemia (CML). We recently developed and reported the synthesis of a first molecule called 17 f that selectively inhibits STAT5 signaling in myeloid leukemia cells and overcomes their resistance to chemotherapeutic agents. To improve the antileukemic effect of 17 f, we synthesized ten analogs of this molecule and analyzed their impact on cell growth, survival, chemoresistance and STAT5 signaling. Two compounds, 7 a and 7 a', were identified as having similar or higher antileukemic effects in various AML and CML cell lines. Both molecules were found to be more effective than 17 f at inhibiting STAT5 activity/expression and suppressing the chemoresistance of CML., (© 2020 Wiley-VCH GmbH.)

Janus kinase 2 (JAK2) is the most important signal-transducing tyrosine kinase in erythropoietic precursor cells. Its malfunction drives several myeloproliferative disorders. Heme is a small metal-ion-carrying molecule that is incorporated into hemoglobin in erythroid precursor cells to transport oxygen. In addition, heme is a signaling molecule and regulator of various biochemical processes. Here, we show that heme exposure leads to hyperphosphorylation of JAK2 in a myeloid cancer cell line. Two peptides identified in JAK2 are heme-regulatory motifs and show low-micromolar affinities for heme. These peptides map to the kinase domain of JAK2, which is essential for downstream signaling. We suggest these motifs to be the interaction sites of heme with JAK2, which drive the heme-induced hyperphosphorylation. The results presented herein could facilitate the development of heme-related pharmacological tools to combat myeloproliferative disorders., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

Execution of the intrinsic apoptotic pathway is controlled by the BCL-2 proteins at the level of the mitochondrial outer membrane (MOM). This family of proteins consists of prosurvival (e.g., BCL-2, MCL-1) and proapoptotic (e.g., BIM, BAD, HRK) members, the functional balance of which dictates the activation of BAX and BAK. Once activated, BAX/BAK form pores in the MOM, resulting in cytochrome c release from the mitochondrial intermembrane space, leading to apoptosome formation, caspase activation, and cleavage of intracellular targets. This pathway is induced by cellular stress including DNA damage, cytokine and growth factor withdrawal, and chemotherapy/drug treatment. A well-documented defense of leukemia cells is to shift the balance of the BCL-2 family in favor of the prosurvival proteins to protect against such intra- and extracellular stimuli. Small molecule inhibitors targeting the prosurvival proteins, named 'BH3 mimetics', have come to the fore in recent years to treat hematological malignancies, both as single agents and in combination with standard-of-care therapies. The most significant example of these is the BCL-2-specific inhibitor venetoclax, given in combination with standard-of-care therapies with great success in AML in clinical trials. As the number and variety of available BH3 mimetics increases, and investigations into applying these novel inhibitors to treat myeloid leukemias continue apace the need to evaluate where we currently stand in this rapidly expanding field is clear.

MYB plays vital roles in regulating proliferation and differentiation of hematopoietic progenitor cells, dysregulation of MYB has been implicated in the pathogenesis of leukemia. Although the transcription of MYB has been well studied, its detailed underlying regulatory mechanisms still remain elusive. Here, we detected the long-range interaction between the upstream regions, -34k and -88k, and the MYB promoter in K562, U937, and HL-60 cells using circularized chromosome conformation capture (4C) assay, which declined when MYB was downregulated during chemical-induced differentiation. The enrichment of enhancer markers, H3K4me1 and H3K27ac, and enhancer activity at the -34k and -88k regions were confirmed by ChIP-qPCR and luciferase assay respectively. ChIP-qPCR showed the dynamic binding of GATA1, TAL1, and CCAAT/enhancer-binding protein (C/EBPβ) at -34k and -88k during differentiation of K562 cells. Epigenome editing by a CRISPR-Cas9-based method showed that H3K27ac at -34k enhanced TF binding and MYB expression, while DNA methylation inhibited MYB expression. Taken together, our data revealed that enhancer elements at -34k are required for MYB expression, TF binding, and epigenetic modification are closely involved in this process in human myeloid leukemia cells.