Leukaemia exposure alters the transcriptional profile and function of BCR::ABL1 negative macrophages in the bone marrow niche.

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.

miR-1202 acts as anti-oncomiR in myeloid leukaemia by down-modulating GATA-1S expression.

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-1S). Given the common hallmark of altered miRNA expression profiles in haematological malignancies and the pro-leukaemic role of GATA-1S, 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-1S 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-1S. 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-1S levels.

The molecular and clinical significance of the Tie/angiopoietin system in leukemia.

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.

Infectious complications after intensive chemotherapy with CLAG-M versus 7+3 for AML and other high-grade myeloid neoplasms.

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.

TYRO3 Knockdown Suppresses the Growth of Myeloid Leukaemia Cells.

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.

Azoxystrobin Induces Apoptosis and Cell Cycle Arrest in Human Leukemia Cells Independent of p53 Expression.

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.

Maintenance therapy with hypomethylating agents for patients with acute myeloid leukemia in first remission not eligible for allogeneic hematopoietic cell transplantation: A systematic review and meta-analysis.

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, I2 = 30 %), and disease control (HR 0.80, 95 % CI 0.70 to 0.91, I2 = 0). A significant decrease was seen in both one year mortality (Risk Ratio [RR] 0.61, 95 % CI 0.48 to 0.77, I2 = 0) and mortality at the end of follow-up (RR 0.77, 95 % CI 0.67 to 0.88, I2 = 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, I2 = 0; 95 % CI 0.69 - 0.91, I2 = 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, I2 = 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.

Comparison of myeloid neoplasms with nonclassic 3q26.2/MECOM versus classic inv(3)/t(3;3) rearrangements reveals diverse clinicopathologic features, genetic profiles, and molecular mechanisms of MECOM activation.

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.

ETV6-NCOA2 fusion induces T/myeloid mixed-phenotype leukemia through transformation of nonthymic hematopoietic progenitor cells.

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.

Decreased CD177pos neutrophils in myeloid neoplasms is associated with NPM1, RUNX1, TET2, and U2AF1 S34F mutations.

A decreased percentage of CD177pos 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 CD177pos 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 CD177pos 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 CD177pos neutrophils when all cases were evaluated. JAK2 (OD 2.5) alteration was associated with increased percentage of CD177pos neutrophils. Differences were noted between diagnostic subgroups with no single mutation associated with decreased CD177pos neutrophils in MDS and CCUS. The findings demonstrate an association between the percentage of CD177pos neutrophils and somatically acquired mutations involving several genes.

A national Danish proof of concept on feasibility and safety of home -based intensive chemotherapy in patients with acute myeloid leukemia.

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.

Immunotherapy for Acute Myeloid Leukemia: Allogeneic hematopoietic cell transplantation is here to stay.

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.

Prognostic relevance of combined IDH1 and NPM1 mutations in the intermediate cytogenetic de novo acute myeloid leukemia.

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.

Metabolic drug survey highlights cancer cell dependencies and vulnerabilities.

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.

Demethylating therapy increases anti-CD123 CAR T cell cytotoxicity against acute myeloid leukemia.

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-4negative anti-CD123 CAR T cell numbers following infusion. Functionally, the CTLA-4negative 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-4negative anti-CD123 CAR T cells.

Human mesenchymal stem cells derived exosomes inhibit the growth of acute myeloid leukemia cells via regulating miR-23b-5p/TRIM14 pathway.

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.