Ablation of Wnt signaling in bone marrow stromal cells overcomes microenvironment-mediated drug resistance in acute myeloid leukemia.

The survival of leukemic cells is significantly influenced by the bone marrow microenvironment, where stromal cells play a crucial role. While there has been substantial progress in understanding the mechanisms and pathways involved in this crosstalk, limited data exist regarding the impact of leukemic cells on bone marrow stromal cells and their potential role in drug resistance. In this study, we identify that leukemic cells prime bone marrow stromal cells towards osteoblast lineage and promote drug resistance. This biased differentiation of stroma is accompanied by dysregulation of the canonical Wnt signaling pathway. Inhibition of Wnt signaling in stroma reversed the drug resistance in leukemic cells, which was further validated in leukemic mice models. This study evaluates the critical role of leukemic cells in establishing a drug-resistant niche by influencing the bone marrow stromal cells. Additionally, it highlights the potential of targeting Wnt signaling in the stroma by repurposing an anthelmintic drug to overcome the microenvironment-mediated drug resistance.

Single cell and bulk RNA expression analyses identify enhanced hexosamine biosynthetic pathway and O-GlcNAcylation in acute myeloid leukemia blasts and stem cells.

Introduction: Acute myeloid leukemia (AML) is the most common acute leukemia in adults with an overall poor prognosis and high relapse rate. Multiple factors including genetic abnormalities, differentiation defects and altered cellular metabolism contribute to AML development and progression. Though the roles of oxidative phosphorylation and glycolysis are defined in AML, the role of the hexosamine biosynthetic pathway (HBP), which regulates the O-GlcNAcylation of cytoplasmic and nuclear proteins, remains poorly defined. Methods: We studied the expression of the key enzymes involved in the HBP in AML blasts and stem cells by RNA sequencing at the single-cell and bulk level. We performed flow cytometry to study OGT protein expression and global O-GlcNAcylation. We studied the functional effects of inhibiting O-GlcNAcylation on transcriptional activation in AML cells by Western blotting and real time PCR and on cell cycle by flow cytometry. Results: We found higher expression levels of the key enzymes in the HBP in AML as compared to healthy donors in whole blood. We observed elevated O-GlcNAc Transferase (OGT) and O-GlcNAcase (OGA) expression in AML stem and bulk cells as compared to normal hematopoietic stem and progenitor cells (HSPCs). We also found that both AML bulk cells and stem cells show significantly enhanced OGT protein expression and global O-GlcNAcylation as compared to normal HSPCs, validating our in silico findings. Gene set analysis showed substantial enrichment of the NF-κB pathway in AML cells expressing high OGT levels. Inhibition of O-GlcNAcylation decreased NF-κB nuclear translocation and the expression of selected NF-κB-dependent genes controlling cell cycle. It also blocked cell cycle progression suggesting a link between enhanced O-GlcNAcylation and NF-κB activation in AML cell survival and proliferation. Discussion: Our study suggests the HBP may prove a potential target, alone or in combination with other therapeutic approaches, to impact both AML blasts and stem cells. Moreover, as insufficient targeting of AML stem cells by traditional chemotherapy is thought to lead to relapse, blocking HBP and O-GlcNAcylation in AML stem cells may represent a novel promising target to control relapse.

Validation of the 2022 European LeukemiaNet risk stratification for acute myeloid leukemia.

This study aimed to validate the 2022 European LeukemiaNet (ELN) risk stratification for acute myeloid leukemia (AML). A total of 624 newly diagnosed AML patients from 1998 to 2014 were included in the analysis. Genetic profiling was conducted using targeted deep sequencing of 45 genes based on recurrent driver mutations. In total, 134 (21.5%) patients had their risk classification reassessed according to the 2022 ELN risk stratification. Among those initially classified as having a favorable risk in 2017 (n = 218), 31 and 3 patients were reclassified as having intermediate risk or adverse risk, respectively. Among the three subgroups, the 2022 ELN favorable-risk group showed significantly longer survival outcomes than the other groups. Within the 2017 ELN intermediate-risk group (n = 298), 21 and 46 patients were reclassified as having favorable risk or adverse risk, respectively, and each group showed significant stratifications in survival outcomes. Some patients initially classified as having adverse risk in 2017 were reclassified into the intermediate-risk group (33 of 108 patients), but no prognostic improvements were observed in this group. A multivariable analysis identified the 2022 ELN risk stratification, age, and receiving allogeneic hematopoietic cell transplantation as significant prognostic factors for survival. The 2022 ELN risk stratification enables more precise decisions for proceeding with allogeneic hematopoietic cell transplantation for AML patients.

A chest CT-based nomogram for predicting survival in acute myeloid leukemia.

BACKGROUND: The identification of survival predictors is crucial for early intervention to improve outcome in acute myeloid leukemia (AML). This study aim to identify chest computed tomography (CT)-derived features to predict prognosis for acute myeloid leukemia (AML). METHODS: 952 patients with pathologically-confirmed AML were retrospectively enrolled between 2010 and 2020. CT-derived features (including body composition and subcutaneous fat features), were obtained from the initial chest CT images and were used to build models to predict the prognosis. A CT-derived MSF nomogram was constructed using multivariate Cox regression incorporating CT-based features. The performance of the prediction models was assessed with discrimination, calibration, decision curves and improvements. RESULTS: Three CT-derived features, including myosarcopenia, spleen_CTV, and SF_CTV (MSF) were identified as the independent predictors for prognosis in AML (P < 0.01). A CT-MSF nomogram showed a performance with AUCs of 0.717, 0.794, 0.796 and 0.792 for predicting the 1-, 2-, 3-, and 5-year overall survival (OS) probabilities in the validation cohort, which were significantly higher than the ELN risk model. Moreover, a new MSN stratification system (MSF nomogram plus ELN risk model) could stratify patients into new high, intermediate and low risk group. Patients with high MSN risk may benefit from intensive treatment (P = 0.0011). CONCLUSIONS: In summary, the chest CT-MSF nomogram, integrating myosarcopenia, spleen_CTV, and SF_CTV features, could be used to predict prognosis of AML.

Unlocking the potential: A novel prognostic index signature for acute myeloid leukemia.

Acute myeloid leukemia (AML) is an aggressive malignancy characterized by challenges in treatment, including drug resistance and frequent relapse. Recent research highlights the crucial roles of tumor microenvironment (TME) in assisting tumor cell immune escape and promoting tumor aggressiveness. This study delves into the interplay between AML and TME. Through the exploration of potential driver genes, we constructed an AML prognostic index (AMLPI). Cross-platform data and multi-dimensional internal and external validations confirmed that the AMLPI outperforms existing models in terms of areas under the receiver operating characteristic curves, concordance index values, and net benefits. High AMLPIs in AML patients were indicative of unfavorable prognostic outcomes. Immune analyses revealed that the high-AMLPI samples exhibit higher expression of HLA-family genes and immune checkpoint genes (including PD1 and CTLA4), along with lower T cell infiltration and higher macrophage infiltration. Genetic variation analyses revealed that the high-AMLPI samples associate with adverse variation events, including TP53 mutations, secondary NPM1 co-mutations, and copy number deletions. Biological interpretation indicated that ALDH2 and SPATS2L contribute significantly to AML patient survival, and their abnormal expression correlates with DNA methylation at cg12142865 and cg11912272. Drug response analyses revealed that different AMLPI samples tend to have different clinical selections, with low-AMLPI samples being more likely to benefit from immunotherapy. Finally, to facilitate broader access to our findings, a user-friendly and publicly accessible webserver was established and available at http://bioinfor.imu.edu.cn/amlpi. This server provides tools including TME-related AML driver genes mining, AMLPI construction, multi-dimensional validations, AML patients risk assessment, and figures drawing.

Targeting PRAME for acute myeloid leukemia therapy.

Despite significant progress in targeted therapy for acute myeloid leukemia (AML), clinical outcomes are disappointing for elderly patients, patients with less fit disease characteristics, and patients with adverse disease risk characteristics. Over the past 10 years, adaptive T-cell immunotherapy has been recognized as a strategy for treating various malignant tumors. However, it has faced significant challenges in AML, primarily because myeloid blasts do not contain unique surface antigens. The preferentially expressed antigen in melanoma (PRAME), a cancer-testis antigen, is abnormally expressed in AML and does not exist in normal hematopoietic cells. Accumulating evidence has demonstrated that PRAME is a useful target for treating AML. This paper reviews the structure and function of PRAME, its effects on normal cells and AML blasts, its implications in prognosis and follow-up, and its use in antigen-specific immunotherapy for AML.

Myeloid neoplasms post cytotoxic therapy: epidemiology, pathogenesis outcomes, prognostic factors, and treatment options.

Myeloid neoplasms post cytotoxic therapy (MN-pCT) are a category includes AML, MDS, and MDS/MPN arising in patients exposed to cytotoxic (DNA-damaging) therapy for an unrelated condition in 2022 version World Health Organization (WHO) classification. With improved survival of patients with tumors, the incidence of MN-pCT after chemotherapy and/or radiation therapy among patients with tumors has gradually risen. However, the outcome of MN-pCT is poorer than that of primary myeloid neoplasms. This review summarizes the current understanding based on existing research, as a foundation for further research on MN-pCT.

Comprehensive Molecular Profiling of NPM1-Mutated Acute Myeloid Leukemia Using RNAseq Approach.

Acute myeloid leukemia (AML) is a complex hematologic malignancy with high morbidity and mortality. Nucleophosmin 1 (NPM1) mutations occur in approximately 30% of AML cases, and NPM1-mutated AML is classified as a distinct entity. NPM1-mutated AML patients without additional genetic abnormalities have a favorable prognosis. Despite this, 30-50% of them experience relapse. This study aimed to investigate the potential of total RNAseq in improving the characterization of NPM1-mutated AML patients. We explored genetic variations independently of myeloid stratification, revealing a complex molecular scenario. We showed that total RNAseq enables the uncovering of different genetic alterations and clonal subtypes, allowing for a comprehensive evaluation of the real expression of exome transcripts in leukemic clones and the identification of aberrant fusion transcripts. This characterization may enhance understanding and guide improved treatment strategies for NPM1mut AML patients, contributing to better outcomes. Our findings underscore the complexity of NPM1-mutated AML, supporting the incorporation of advanced technologies for precise risk stratification and personalized therapeutic strategies. The study provides a foundation for future investigations into the clinical implications of identified genetic variations and highlights the importance of evolving diagnostic approaches in leukemia management.

m6A-dependent upregulation of DDX21 by super-enhancer-driven IGF2BP2 and IGF2BP3 facilitates progression of acute myeloid leukaemia.

BACKGROUND: Acute myeloid leukaemia (AML) is a haematological malignancy with unfavourable prognosis. Despite the effectiveness of chemotherapy and targeted therapy, relapse or drug resistance remains a major threat to AML patients. N6-methyladenosine (m6A) RNA methylation and super-enhancers (SEs) are extensively involved in the leukaemogenesis of AML. However, the potential relationship between m6A and SEs in AML has not been elaborated. METHODS: Chromatin immunoprecipitation (ChIP) sequencing data from Gene Expression Omnibus (GEO) cohort were analysed to search SE-related genes. The mechanisms of m6 A-binding proteins IGF2BP2 and IGF2BP3 on DDX21 were explored via methylated RNA immunoprecipitation (MeRIP) assays, RNA immunoprecipitation (RIP) assays and luciferase reporter assays. Then we elucidated the roles of DDX21 in AML through functional assays in vitro and in vivo. Finally, co-immunoprecipitation (Co-IP) assays, RNA sequencing and ChIP assays were performed to investigate the downstream mechanisms of DDX21. RESULTS: We identified two SE-associated transcripts IGF2BP2 and IGF2BP3 in AML. High enrichment of H3K27ac, H3K4me1 and BRD4 was observed in IGF2BP2 and IGF2BP3, whose expression were driven by SE machinery. Then IGF2BP2 and IGF2BP3 enhanced the stability of DDX21 mRNA in an m6A-dependent manner. DDX21 was highly expressed in AML patients, which indicated a poor survival. Functionally, knockdown of DDX21 inhibited cell proliferation, promoted cell apoptosis and led to cell cycle arrest. Mechanistically, DDX21 recruited transcription factor YBX1 to cooperatively trigger ULK1 expression. Moreover, silencing of ULK1 could reverse the promoting effects of DDX21 overexpression in AML cells. CONCLUSIONS: Dysregulation of SE-IGF2BP2/IGF2BP3-DDX21 axis facilitated the progression of AML. Our findings provide new insights into the link between SEs and m6A modification, elucidate the regulatory mechanisms of IGF2BP2 and IGF2BP3 on DDX21, and reveal the underlying roles of DDX21 in AML.

[Safety and efficacy of 7-day administration of azacitidine and venetoclax combination therapy (7+7 therapy)].

Acute myelogenous leukemia (AML) has a poor prognosis in patients who are ineligible for intensive chemotherapy. The combination of azacitidine and venetoclax has been shown to have high overall efficiency and remission rates, even in patients ineligible for aggressive chemotherapy. However, myelosuppression is often prolonged after treatment, and infection can also occur. Severe myelosuppression is often addressed by dose titration, but specific dose titration methods have not been clarified. We used the standard induction therapy with azacitidine plus venetoclax, and if blasts decreased to 20% or less, switched to 7+7 therapy to shorten venetoclax to 7 days starting from the next cycle. In the 19 patients we treated (median age 80 years), response rate above MLFS was 100%, CR 57.9%, CRc (CR+CRi) 78.8%, median OS 693 days, median PFS 458 days, and median OS was not reached in previously untreated patients. This indicates that 7+7 is a highly effective and well-tolerated treatment.

[Fulminant Clostridioides difficile infection during treatment with FLT3 inhibitor for acute myeloid leukemia].

An 80-year-old man with FLT3-TKD mutation-positive acute myeloid leukemia (AML) relapsed during consolidation therapy with venetoclax/azacitidine and was started on gilteritinib as salvage therapy. On the day after treatment initiation, febrile neutropenia was observed, but the fever resolved promptly after initiation of antimicrobial therapy. On the fifth day after completion of antimicrobial therapy, the patient experienced fever and watery diarrhea over 10 times a day, and a diagnosis of Clostridioides difficile infection (CDI) was made based on stool examination. The patient was treated with intravenous metronidazole, but renal dysfunction, hypotension, and hypoxemia developed, and a CT scan showed pleural and intraperitoneal effusion, significant intestinal wall thickening, and intestinal dilatation. Fidaxomicin was started under general monitoring in the intensive care unit and response was achieved. The patient was discharged from the intensive care unit on the 18th day after the onset of CDI. We report this case not only due to the rarity of fulminant CDI during AML treatment, but also because it is a valuable example of effective treatment of fulminant CDI with fidaxomicin.

[Veno-venous extracorporeal membrane oxygenation for capillary leak syndrome during induction chemotherapy in acute myeloid leukemia].

A 44-year-old woman was diagnosed with acute myeloid leukemia (RUNX1::RUNX1T1 translocation) and received induction chemotherapy with idarubicin hydrochloride and cytosine arabinoside. The pneumonia that had been present since admission worsened, and a drug-induced skin rash appeared. On day 17, she presented with respiratory failure and shock, complicated by hemoconcentration and hypoalbuminemia. This was considered capillary leak syndrome due to pneumonia and drug allergy, so she was started on pulse steroid therapy and IVIG, and was intubated on the same day. On day 18, venovenous-extracorporeal membrane oxygenation (VV-ECMO) was started due to worsening blood gas parameters despite ventilatory management. Bronchoalveolar lavage fluid was serous, and both blood and sputum cultures yielded negative. The patient was weaned from VV-ECMO on day 26 as the pneumonia improved with recovery of hematopoiesis. She was disoriented, and a CT scan on day 28 revealed cerebral hemorrhage. Her strength recovered with rehabilitation. After induction chemotherapy, RUNX1::RUNX1T1 mRNA was not detected in bone marrow. The patient received consolidation chemotherapy, and has maintained complete remission. Severe respiratory failure during induction chemotherapy for acute leukemia can be fatal, but VV-ECMO may be lifesaving.

Targeting Metabolic Dependencies Fueling the TCA Cycle to Circumvent Therapy Resistance in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is one of the most prevalent blood cancers, characterized by a dismal survival rate. This poor outcome is largely attributed to AML cells that persist despite treatment and eventually result in relapse. Relapse-initiating cells exhibit diverse resistance mechanisms, encompassing genetic factors and, more recently discovered, nongenetic factors such as metabolic adaptations. Leukemic stem cells (LSC) rely on mitochondrial metabolism for their survival, whereas hematopoietic stem cells primarily depend on glycolysis. Furthermore, following treatments such as cytarabine, a standard in AML treatment for over four decades, drug-persisting leukemic cells exhibit an enhanced reliance on mitochondrial metabolism. In this issue of Cancer Research, two studies investigated dependencies of AML cells on two respiratory substrates, α-ketoglutarate and lactate-derived pyruvate, that support mitochondrial oxidative phosphorylation (OXPHOS) following treatment with the imipridone ONC-213 and the BET inhibitor INCB054329, respectively. Targeting lactate utilization by interfering with monocarboxylate transporter 1 (MCT1 or SLC16A1) or lactate dehydrogenase effectively sensitized cells to BET inhibition in vitro and in vivo. In addition, ONC-213 affected αKGDH, a pivotal NADH-producing enzyme of the TCA cycle, to induce a mitochondrial stress response through ATF4 activation that diminished the expression of the antiapoptotic protein MCL1, consequently promoting apoptosis of AML cells. In summary, targeting these mitochondrial dependencies might be a promising strategy to kill therapy-naïve and treatment-resistant OXPHOS-reliant LSCs and to delay or prevent relapse. See related articles by Monteith et al., p. 1101 and Su et al., p. 1084.

Sweet syndrome induced by FLT3 inhibitors: case report and literature review.

BACKGROUND: Acute febrile neutrophilic dermatosis, also commonly referred to as Sweet syndrome, is often associated with tumors, infections, immune disorders and medications. FLT3 inhibitor-induced Sweet syndrome is a rare complication. METHODS AND RESULTS: We report a patient with relapsed and refractory acute monocytic leukemia harboring high-frequency FLT3-ITD and DNMT3a mutations. The FLT3 inhibitor gilteritinib was administered for reinduction therapy after failure of chemotherapy with a combination of venetoclax, decitabine, aclarubicin, cytarabine and granulocyte colony-stimulating factor. The leukemia patient achieved remission after 1 month of treatment. However, Sweet syndrome induced by gilteritinib, which was confirmed by skin biopsy, developed during induction therapy. Similar cases of Sweet syndrome following FLT3 inhibitor therapy for acute myeloid leukemia were reviewed. CONCLUSION: Attention should be given to this rare complication when FLT3 inhibitors are used for acute myeloid leukemia therapy, and appropriate treatments need to be administered in a timely manner.

Haploidentical and matched unrelated donor allogeneic hematopoietic stem cell transplantation offer similar survival outcomes for acute leukemia.

BACKGROUND: Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has emerged as an effective approach for acute leukemia, primarily due to the inherent difficulty in finding human leukocyte antigen-matched unrelated donors (MUD). Nevertheless, it remains uncertain whether haplo-HSCT and MUD-HSCT can provide comparable outcomes in patients with acute leukemia. AIMS: This study aimed to assess the overall survival (OS) and leukemia-free survival (LFS) outcomes between the MUD-HSCT and haplo-HSCT groups. METHODS AND RESULTS: This retrospective analysis encompassed adult patients with acute leukemia undergoing the initial allo-HSCT. Among these 85 patients, we stratified 33 patients into the MUD-HSCT group and 52 to the haplo-HSCT group. The primary outcomes were OS and LFS. The median OS was not reached in the haplo-HSCT group, while it reached 29.8 months in patients undergoing MUD-HSCT (p = .211). Likewise, the median LFS periods were 52.6 months in the haplo-HSCT group and 12.7 months in the MUD-HSCT group (p = .212). Importantly, neither the OS nor LFS showed substantial differences between the MUD-HSCT and haplo-HSCT groups. Furthermore, univariate analyses revealed that haplo-HSCT did not demonstrate a significantly higher risk of worse LFS (hazard ratio [HR], 0.69; 95% confidence interval [CI], 0.38-1.25; p = .216) or OS (HR, 0.67; 95% CI, 0.36-1.26; p = .214) than MUD-HSCT. Notably, a high European Group for Blood and Marrow Transplantation risk score (HR, 1.44; 95% CI, 1.10-1.87; p = .007) and non-complete remission (HR, 2.48; 95% CI, 1.17-5.23; p = .017) were significantly correlated with worse OS. CONCLUSION: Haplo-HSCT may serve as an alternative to MUD-HSCT for the treatment of acute leukemia, offering similar survival outcomes.

Structure-guided functional suppression of AML-associated DNMT3A hotspot mutations.

DNA methyltransferases DNMT3A- and DNMT3B-mediated DNA methylation critically regulate epigenomic and transcriptomic patterning during development. The hotspot DNMT3A mutations at the site of Arg822 (R882) promote polymerization, leading to aberrant DNA methylation that may contribute to the pathogenesis of acute myeloid leukemia (AML). However, the molecular basis underlying the mutation-induced functional misregulation of DNMT3A remains unclear. Here, we report the crystal structures of the DNMT3A methyltransferase domain, revealing a molecular basis for its oligomerization behavior distinct to DNMT3B, and the enhanced intermolecular contacts caused by the R882H or R882C mutation. Our biochemical, cellular, and genomic DNA methylation analyses demonstrate that introducing the DNMT3B-converting mutations inhibits the R882H-/R882C-triggered DNMT3A polymerization and enhances substrate access, thereby eliminating the dominant-negative effect of the DNMT3A R882 mutations in cells. Together, this study provides mechanistic insights into DNMT3A R882 mutations-triggered aberrant oligomerization and DNA hypomethylation in AML, with important implications in cancer therapy.

Exploring the role of GHRH antagonist MIA-602 in overcoming Doxorubicin-resistance in acute myeloid leukemia.

Acute myeloid leukemia (AML) is characterized by the rapid proliferation of mutagenic hematopoietic progenitors in the bone marrow. Conventional therapies include chemotherapy and bone marrow stem cell transplantation; however, they are often associated with poor prognosis. Notably, growth hormone-releasing hormone (GHRH) receptor antagonist MIA-602 has been shown to impede the growth of various human cancer cell lines, including AML. This investigation examined the impact of MIA-602 as monotherapy and in combination with Doxorubicin on three Doxorubicin-resistant AML cell lines, KG-1A, U-937, and K-562. The in vitro results revealed a significant reduction in cell viability for all treated wild-type cells. Doxorubicin-resistant clones were similarly susceptible to MIA-602 as the wild-type counterpart. Our in vivo experiment of xenografted nude mice with Doxorubicin-resistant K-562 revealed a reduction in tumor volume with MIA-602 treatment compared to control. Our study demonstrates that these three AML cell lines, and their Doxorubicin-resistant clones, are susceptible to GHRH antagonist MIA-602.

Efficacy of delayed pegfilgrastim administration following consolidation therapy with high-dose cytarabine (HiDAC) in acute myeloid leukemia (AML) patients.

PURPOSE: To study the effects of delaying pegfilgrastim administration following high-dose cytarabine (HiDAC) consolidation in AML patients on time to neutrophil count recovery, infectious complications, and survival. METHODS: Single-center retrospective chart review of 55 patients receiving pegfilgrastim as early administration (within 72 h) or delayed administration (after 72 h) of HiDAC. RESULTS: The difference in neutrophil recovery time was similar between the early and delayed groups (18 days versus 19 days, p < 0.28). Infections were seen in four patients in the early administration group following chemotherapy compared to none in the delayed group (p = 0.04). Febrile neutropenia rates were also decreased in the delayed administration group (23.1% versus 10.3%, p = 0.28) as well as a trend towards longer median survival (16 months versus 19 months, p = 0.69) and overall survival (21 months versus 31 months, p = 0.47). CONCLUSION: A difference in time to neutrophil recovery was not observed between the early and delayed administration groups yet decreased infectious complications may support the delayed administration of pegfilgrastim in these patients.