Acute myeloid leukemia: current progress and future directions

Automated manufacture of ΔNPM1 TCR-engineered T cells for AML therapy

Acute myeloid leukemia (AML) is a heterogeneous malignancy that requires further therapeutic improvement, especially for the elderly and for subgroups with poor prognosis. A recently discovered T cell receptor (TCR) targeting mutant nucleophosmin 1 (ΔNPM1) presents an attractive option for the development of a cancer antigen-targeted cellular therapy. Manufacturing of TCR-modified T cells, however, is still limited by a complex, time-consuming, and laborious procedure. Therefore, this study specifically addressed the requirements for a scaled manufacture of ΔNPM1-specific T cells in an automated, closed, and good manufacturing practice-compliant process. Starting from cryopreserved leukapheresis, 2E8 CD8-positive T cells were enriched, activated, lentivirally transduced, expanded, and finally formulated. By adjusting and optimizing culture conditions, we additionally reduced the manufacturing time from 12 to 8 days while still achieving a clinically relevant yield of up to 5.5E9 ΔNPM1 TCR-engineered T cells. The cellular product mainly consisted of highly viable CD8-positive T cells with an early memory phenotype. ΔNPM1 TCR CD8 T cells manufactured with the optimized process showed specific killing of AML in vitro and in vivo. The process has been implemented in an upcoming phase 1/2 clinical trial for the treatment of NPM1-mutated AML.

IL-33-dependent NF-κB activation inhibits apoptosis and drives chemoresistance in acute myeloid leukemia

BACKGROUND

Despite recent advances in therapeutic regimens, the prognosis of acute myeloid leukemia (AML) remains poor. Following our previous finding that interleukin-33 (IL-33) promotes cell survival along with activated NF-κB in AML, we further investigated the role of NF-κB during leukemia development.

METHODS

Flow cytometry was performed to value the apoptosis and proliferation. qRT-PCR and western blot were performed to detect the expression of IL-6, active caspase 3, BIRC2, Bcl-2, and Bax, as well as activated NF-κB p65 and AKT. Finally, xenograft mouse models and AML patient samples were used to verify the findings observed in AML cell lines.

RESULTS

IL-33-mediated NF-κB activation in AML cell lines contributes to a reduction in apoptosis, an increase in proliferation rate as well as a decrease in drug sensitivity, which were reversed by NF-κB inhibitor, Bay-117085. Moreover, IL-33 decreased the expression of active caspase-3 while increasing the levels of BIRC2, Bcl-2, and Bax, and these effects were blocked by Bay-117085. Additionally, NF-κB activation induced by IL-33 increases the production of IL-6 and autocrine activation of AKT. Co-culture of bone marrow stroma with AML cells resulted in increased IL-33 expression by leukemia cells, along with decreased apoptosis level and reduced drug sensitivity. Finally, we confirmed the in vivo pro-tumor effect mediated by IL-33/ NF-κB axis using a xenograft model of AML.

CONCLUSION

Our data indicate that IL-33/IL1RL1-dependent signaling contributes to AML cell activation of NF-κB, which in turn causes autocrine IL-6-induced activation of pAKT, supporting IL-33/NF-κB/pAKT as a potential target for AML therapy.

Silencing of the DNA damage repair regulator PPP1R15A sensitizes acute myeloid leukemia cells to chemotherapy

Acute Myeloid Leukemia (AML) is a life-threatening disease whose induction treatment consists of combination chemotherapy with Idarubicin and Cytarabine for fit patients. Treatment failures are frequent, urging the need for novel treatments for this disease. The DNA Damage Response Mechanism (DDR) comprises numerous molecules and pathways intended to arrest the cell cycle until DNA damage is repaired or else drive the cell to apoptosis. AML-derived cell lines after treatment with Idarubicin and Cytarabine were used for studying the expression profile of 84 DDR genes, through PCR arrays. Utilizing de novo AML patient and control samples we studied the expression of PPP1R15A, CDKN1A, GADD45A, GADD45G, and EXO1. Next, we performed PPP1R15A silencing in AML cell lines in two separate experiments using siRNA and CRISPR-cas9, respectively. Our findings highlight that DDR regulators demonstrate increased expression in patients with high cytogenetic risk possibly reflecting increased genotoxic stress. Especially, PPP1R15A is mainly involved in the recovery of the cells from stress and it was the only DDR gene upregulated in AML patients. The PPP1R15A silencing resulted in decreased viability of Idarubicin and Cytarabine-treated cell lines, in contrast to untreated cells. These findings shed light on new strategies to enhance chemotherapy efficacy and demonstrate that PPP1R15A is an important DDR regulator in AML and its downregulation might be a safe and effective way to increase sensitivity to chemotherapy in this disease.

In silico predicted compound targeting the IQGAP1-GRD domain selectively inhibits growth of human acute myeloid leukemia

Acute myeloid leukemia (AML) is fatal in the majority of adults. Identification of new therapeutic targets and their pharmacologic modulators are needed to improve outcomes. Previous studies had shown that immunization of rabbits with normal peripheral WBCs that had been incubated with fluorodinitrobenzene elicited high titer antibodies that bound to a spectrum of human leukemias. We report that proteomic analyses of immunoaffinity-purified lysates of primary AML cells showed enrichment of scaffolding protein IQGAP1. Immunohistochemistry and gene-expression analyses confirmed IQGAP1 mRNA overexpression in various cytogenetic subtypes of primary human AML compared to normal hematopoietic cells. shRNA knockdown of IQGAP1 blocked proliferation and clonogenicity of human leukemia cell-lines. To develop small molecules targeting IQGAP1 we performed in-silico screening of 212,966 compounds, selected 4 hits targeting the IQGAP1-GRD domain, and conducted SAR of the 'fittest hit' to identify UR778Br, a prototypical agent targeting IQGAP1. UR778Br inhibited proliferation, induced apoptosis, resulted in G2/M arrest, and inhibited colony formation by leukemia cell-lines and primary-AML while sparing normal marrow cells. UR778Br exhibited favorable ADME/T profiles and drug-likeness to treat AML. In summary, AML shows response to IQGAP1 inhibition, and UR778Br, identified through in-silico studies, selectively targeted AML cells while sparing normal marrow.

Polyphyllin I induces rapid ferroptosis in acute myeloid leukemia through simultaneous targeting PI3K/SREBP-1/SCD1 axis and triggering of lipid peroxidation

Acute myeloid leukemia (AML) is a malignant disease that is difficult to completely cure. Polyphyllin I (PPI), a steroidal saponin isolated from Paris polyphylla, has exhibited multiple biological activities. Here, we discovered the superior cytotoxicity of PPI on AML cells MOLM-13 with an IC50 values of 0.44 ± 0.09 μM. Mechanically, PPI could cause ferroptosis via the accumulation of intracellular iron concentration and triggering lipid peroxidation. Interestingly, PPI could induced stronger ferroptosis in a short time of about 6 h compared to erastin. Furthermore, we demonstrate that PPI-induced rapid ferroptosis is due to the simultaneous targeting PI3K/SREBP-1/SCD1 axis and triggering lipid peroxidation, and PI3K inhibitor Alpelisib can enhance the activity of erastin-induced ferroptosis. Molecular docking simulations and kinase inhibition assays demonstrated that PPI is a PI3K inhibitor. In addition, PPI significantly inhibited tumor progression and prolonged mouse survival at 4 mg/kg with well tolerance. In summary, our study highlights the therapeutic potential of PPI for AML and shows its unique dual mechanism.

ONC212 enhances YM155 cytotoxicity by triggering SLC35F2 expression and NOXA-dependent MCL1 degradation in acute myeloid leukemia cells

Although the anticancer activity of ONC212 has been reported, the precise mechanism underlying its apoptotic effects remains unclear. In this study, we investigated the apoptotic mechanism of ONC212 in acute myeloid leukemia (AML) cells. ONC212 induces apoptosis, MCL1 downregulation, and mitochondrial depolarization in AML U937 cells. Ectopic MCL1 expression alleviates mitochondria-mediated apoptosis in ONC212-treated U937 cells. ONC212 triggers AKT phosphorylation, inducing NOX4-dependent ROS production and promoting HuR transcription. HuR-mediated ATF4 mRNA stabilization stimulates NOXA and SLC35F2 expression; ONC212-induced upregulation of NOXA leads to MCL1 degradation. The synergistic effect of ONC212 on YM155 cytotoxicity was dependent on increased SLC35F2 expression. In addition, YM155 feedback facilitated the activation of the ONC212-induced signaling pathway. A similar mechanism explains ONC212- and ONC212/YM155-induced AML HL-60 cell death. The continuous treatment of U937 cells with the benzene metabolite hydroquinone (HQ) generated U937/HQ cells, exhibiting enhanced responsiveness to the cytotoxic effects of ONC212. In U937/HQ cells, ONC212 triggered apoptosis through NOXA-mediated MCL1 downregulation, enhancing YM155 cytotoxicity. Collectively, our data suggested that ONC212 upregulated SLC35F2 expression and triggered NOXA-mediated MCL1 degradation in U937, U937/HQ, and HL-60 cells by activating the AKT/NOX4/HuR/ATF4 pathway. The ONC212-induced signaling pathway showed anti-AML activity and enhanced YM155 cytotoxicity.

Targeting the innate immune system in pediatric and adult AML

While the introduction of T cell-based immunotherapies has improved outcomes in many cancer types, the development of immunotherapies for both adult and pediatric AML has been relatively slow and limited. In addition to the need to identify suitable target antigens, a better understanding of the immunosuppressive tumor microenvironment is necessary for the design of novel immunotherapy approaches. To date, most immune characterization studies in AML have focused on T cells, while innate immune lineages such as monocytes, granulocytes and natural killer (NK) cells, received less attention. In solid cancers, studies have shown that innate immune cells, such as macrophages, myeloid-derived suppressor cells and neutrophils are highly plastic and may differentiate into immunosuppressive cells depending on signals received in their microenvironment, while NK cells appear to be functionally impaired. Hence, an in-depth characterization of the innate immune compartment in the TME is urgently needed to guide the development of immunotherapeutic interventions for AML. In this review, we summarize the current knowledge on the innate immune compartment in AML, and we discuss how targeting its components may enhance T cell-based- and other immunotherapeutic approaches.

Long non-coding RNA as potential diagnostic markers for acute myeloid leukemia: A systematic review and meta-analysis

BACKGROUND

Acute myeloid leukemia (AML) is aggressive type of hematological malignancy. Its poses challenges in early diagnosis, necessitating the identification of an effective biomarker. This study aims to assess the diagnostic accuracy of long noncoding RNAs (lncRNA) in the diagnosis of AML through a meta-analysis. The study is registered on the PROSPERO website with the number 493518.

METHOD

A literature search was conducted in the PubMed, Embase, Hinari, and the Scopus databases to identify relevant studies. We pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the summary receiver operating characteristics (ROC) using Stata 14.1 software. Heterogeneity between studies was determined through the I2 statistic and Cochran-Q test. A random effect model was chosen due to significant heterogeneity among included studies. Meta-regression and subgroup analysis were performed to assess the potential source of heterogeneity. Furthermore, potential publication bias was estimated using Deek's funnel plot asymmetry test.

RESULTS

A total of 14 articles covering 19 studies were included in this meta-analysis comprising 1588 AML patients and 529 healthy participants. The overall pooled sensitivity, specificity, PLR, NLR, DOR, and the area under the summary ROC curve were 0.85 (95% CI = 0.78-0.91), 0.82 (95% CI = 0.72-0.89), 4.7 (95% CI = 2.9-7.4), 0.18 (95% CI = 0.12-0.28), 26 (95% CI = 12-53), and 0.90 (95% CI = 0.87-0.93), respectively. Moreover, lncRNAs from non-bone marrow mononuclear cells (BMMC) had superior diagnostic value with pooled sensitivity, specificity, and AUC were 0.93, 0.82, and 0.95, respectively.

CONCLUSION

This meta-analysis demonstrated that circulating lncRNAs can serve as potential diagnostic markers for AML. High accuracy of diagnosis was observed in non-BMMC lncRNAs, given cutoff value, and the GADPH internal reference gene used. However, further studies with large sample size are required to confirm our results.

INSPIRED Symposium Part 5: Expanding the Use of CAR T Cells in Children and Young Adults

Chimeric antigen receptor (CAR) T cell therapy has demonstrated remarkable efficacy in relapsed/refractory (r/r) B cell malignancies, including in pediatric patients with acute lymphoblastic leukemia (ALL). Expanding this success to other hematologic and solid malignancies is an area of active research and, although challenges remain, novel solutions have led to significant progress over the past decade. Ongoing clinical trials for CAR T cell therapy for T cell malignancies and acute myeloid leukemia (AML) have highlighted challenges, including antigen specificity with off-tumor toxicity and persistence concerns. In T cell malignancies, notable challenges include CAR T cell fratricide and prolonged T cell aplasia, which are being addressed with strategies such as gene editing and suicide switch technologies. In AML, antigen identification remains a significant barrier, due to shared antigens across healthy hematopoietic progenitor cells and myeloid blasts. Strategies to limit persistence and circumvent the immunosuppressive tumor microenvironment (TME) created by AML are also being explored. CAR T cell therapies for central nervous system and solid tumors have several challenges, including tumor antigen heterogeneity, immunosuppressive and hypoxic TME, and potential for off-target toxicity. Numerous CAR T cell products have been designed to overcome these challenges, including "armored" CARs and CAR/T cell receptor (TCR) hybrids. Strategies to enhance CAR T cell delivery, augment CAR T cell performance in the TME, and ensure the safety of these products have shown promising results. In this manuscript, we will review the available evidence for CAR T cell use in T cell malignancies, AML, central nervous system (CNS), and non-CNS solid tumor malignancies, and recommend areas for future research.

PROteolysis-Targeting Chimeras (PROTACs) in leukemia: overview and future perspectives

Leukemia is a heterogeneous group of life-threatening malignant disorders of the hematopoietic system. Immunotherapy, radiotherapy, stem cell transplantation, targeted therapy, and chemotherapy are among the approved leukemia treatments. Unfortunately, therapeutic resistance, side effects, relapses, and long-term sequelae occur in a significant proportion of patients and severely compromise the treatment efficacy. The development of novel approaches to improve outcomes is therefore an unmet need. Recently, novel leukemia drug discovery strategies, including targeted protein degradation, have shown potential to advance the field of personalized medicine for leukemia patients. Specifically, PROteolysis-TArgeting Chimeras (PROTACs) are revolutionary compounds that allow the selective degradation of a protein by the ubiquitin-proteasome system. Developed against a wide range of cancer targets, they show promising potential in overcoming many of the drawbacks associated with conventional therapies. Following the exponential growth of antileukemic PROTACs, this article reviews PROTAC-mediated degradation of leukemia-associated targets. Chemical structures, in vitro and in vivo activities, pharmacokinetics, pharmacodynamics, and clinical trials of PROTACs are critically discussed. Furthermore, advantages, challenges, and future perspectives of PROTACs in leukemia are covered, in order to understand the potential that these novel compounds may have as future drugs for leukemia treatment.

Tailoring Therapy in Older Adults With Hematologic Malignancies

Hematologic malignancies most often present in the sixth or seventh decade of life. Even so, many older adults may be unable to tolerate standard chemotherapy or require supplementary care or dose adjustments to do so. Both in community and academic centers, geriatric assessment (GA) can be used to improve the care of older adults with blood cancers. For example, hematologic oncologists can use GA to guide treatment selection, adjusting for patient frailty and goals, as well as prompt initiation of enhanced supportive care. After initial therapy, GA can improve the identification of older adults with aggressive myeloid malignancies who would benefit from hematopoietic cell transplantation (HCT), inform shared decision making, as well as allow transplanters to tailor conditioning regimen, donor selection, graft-versus-host disease prophylaxis, and pre- and post-HCT treatments. As in HCT, GA can improve the care of older patients with relapsed lymphoma or multiple myeloma eligible for chimeric antigen receptor-T therapy, identifying patients at higher risk for toxicity and providing a baseline for subsequent neurocognitive testing. Here, we review the data supporting GA for the care of older adults with blood cancers, from the community to the academic center. In addition, we explore future directions to optimize outcomes for older adults with hematologic malignancies.

Treatment outcomes of pediatrics acute myeloid leukemia (AML) and associated factors in the country's tertiary referral hospital, Ethiopia

BACKGROUND

Pediatric Acute Myeloid Leukemia (AML) is a major cause of morbidity and mortality in children with cancer in Africa and other developing continents. Systemic chemotherapy and effective supportive care have significantly contributed to increased survival rates of pediatric AML in developed countries reaching approximately 70%. There is a paucity of contextual data regarding overall and event-free survival outcomes in children with acute myeloid leukemia in developing countries and most centers in Africa provide palliative care. The objective of this study was to assess the overall survival, event-free survival, and associated factors in pediatric AML patients treated in Ethiopia.

METHODS

This retrospective study was conducted on Pediatric AML patients treated at Tikur Anbessa Hospital between January 1, 2015, and May 30, 2022. The socio-demographic profile of patients, the clinical characteristics, the biochemical and morphological subtypes of AML were analyzed using SPSS version 25. The Kaplan-Meier survival curve was used to estimate the probabilities of overall and event-free survival. Statistical significance was set at p < 0.05.

RESULTS

A total of 92 children with AML were included in this study. The median age at diagnosis was 7 years (interquartile range: 5-10 years) with a slight male predominance. The median duration of symptoms was one month. Neutropenic fever (56, 86.2%) was the most common complication during treatment. About 29.3% of the patients succumbed to early death. The corresponding 1-year and 3-year OS probabilities were 28.2% and 23% respectively. The median event-free survival time for all pediatric AML patients was one-month (95% CI: 0.77-1.23). The determinants of poorer survival outcomes were FAB subtype, type of protocol used, and signs of CNS involvement (p < 0.05).

CONCLUSION

The survival rates of children from AML were low in the study setting. More than 25% of AML patients succumbed to early death, and febrile neutropenia was the most common complication. Effective supportive and therapeutic measures should be taken to manage febrile neutropenia and to prevent early death in AML patients.

Valrubicin-loaded immunoliposomes for specific vesicle-mediated cell death in the treatment of hematological cancers

We created valrubicin-loaded immunoliposomes (Val-ILs) using the antitumor prodrug valrubicin, a hydrophobic analog of daunorubicin. Being lipophilic, valrubicin readily incorporated Val-lLs that were loaded with specific antibodies. Val-ILs injected intravenously rapidly reached the bone marrow and spleen, indicating their potential to effectively target cancer cells in these areas. Following the transplantation of human pediatric B-cell acute lymphoblastic leukemia (B-ALL), T-cell acute lymphoblastic leukemia (T-ALL), or acute myeloid leukemia (AML) in immunodeficient NSG mice, we generated patient-derived xenograft (PDX) models, which were treated with Val-ILs loaded with antibodies to target CD19, CD7 or CD33. Only a small amount of valrubicin incorporated into Val-ILs was needed to induce leukemia cell death in vivo, suggesting that this approach could be used to efficiently treat acute leukemia cells. We also demonstrated that Val-ILs could reduce the risk of contamination of CD34+ hematopoietic stem cells by acute leukemia cells during autologous peripheral blood stem cell transplantation, which is a significant advantage for clinical applications. Using EL4 lymphoma cells on immunocompetent C57BL/6 mice, we also highlighted the potential of Val-ILs to target immunosuppressive cell populations in the spleen, which could be valuable in impairing cancer cell expansion, particularly in lymphoma cases. The most efficient Val-ILs were found to be those loaded with CD11b or CD223 antibodies, which, respectively, target the myeloid-derived suppressor cells (MDSC) or the lymphocyte-activation gene 3 (LAG-3 or CD223) on T4 lymphocytes. This study provides a promising preclinical demonstration of the effectiveness and ease of preparation of Val-ILs as a novel nanoparticle technology. In the context of hematological cancers, Val-ILs have the potential to be used as a precise and effective therapy based on targeted vesicle-mediated cell death.

Relapse Prevention in Acute Myeloid Leukemia: The Role of Immunotherapy with Histamine Dihydrochloride and Low-Dose Interleukin-2

The treatment and management of acute myeloid leukemia (AML) has improved in recent decennia by targeted therapy for subgroups of patients, expanded indications for allogeneic stem cell transplantation (allo-SCT) and surveillance of residual or arising leukemia. However, hematological relapse among patients who have attained complete remission (CR) after the initial courses of chemotherapy remains a significant cause of morbidity and mortality. Here, we review an immunotherapeutic option using histamine dihydrochloride and low-dose interleukin-2 (HDC/LD-IL-2) for remission maintenance in AML. The treatment is approved in Europe in the post-consolidation phase to avoid relapse among patients in CR who are not candidates for upfront allo-SCT. We present aspects of the purported anti-leukemic mechanism of this regimen, including translation of preclinical results into the clinical setting, along with relapse prevention in subgroups of patients. We consider that HDC/LD-IL-2 is a conceivable option for younger adults, in particular patients with AML of normal karyotype and those with favorable responses to the initial chemotherapy. HDC/LD-IL-2 may form an emerging landscape of remission maintenance in AML.

Homoharringtonine: updated insights into its efficacy in hematological malignancies, diverse cancers and other biomedical applications

HHT has emerged as a notable compound in the realm of cancer treatment, particularly for hematological malignancies. Its multifaceted pharmacological properties extend beyond traditional applications, warranting an extensive review of its mechanisms and efficacy. This review aims to synthesize comprehensive insights into the efficacy of HHT in treating hematological malignancies, diverse cancers, and other biomedical applications. It focuses on elucidating the molecular mechanisms, therapeutic potential, and broader applications of HHT. A comprehensive search for peer-reviewed papers was conducted across various academic databases, including ScienceDirect, Web of Science, Scopus, American Chemical Society, Google Scholar, PubMed/MedLine, and Wiley. The review highlights HHT's diverse mechanisms of action, ranging from its role in leukemia treatment to its emerging applications in managing other cancers and various biomedical conditions. It underscores HHT's influence on cellular processes, its efficacy in clinical settings, and its potential to alter pathological pathways. HHT demonstrates significant promise in treating various hematological malignancies and cancers, offering a multifaceted approach to disease management. Its ability to impact various physiological pathways opens new avenues for therapeutic applications. This review provides a consolidated foundation for future research and clinical applications of HHT in diverse medical fields.

A chemically adjustable BMP6-IL6 axis in mesenchymal stem cells drives acute myeloid leukemia cell differentiation

Chemotherapy alone or in combination with allogeneic stem cell transplantation has been the standard of care for acute myeloid leukemia (AML) for decades. Leukemia relapse with limited treatment options remains the main cause of treatment failure. Therefore, an effective and safe approach to improve treatment outcomes is urgently needed for most AML patients. Mesenchymal stem cells (MSCs) have been reported to efficiently induce apoptosis and shape the fate of acute myeloid leukemia cells. Here, we identified LG190155 as a potent compound that enhances the antileukemia efficiency of MSCs. Pretreatment of MSCs with LG190155 significantly provoked differentiation in both AML patient-derived primary leukemia cells and AML cell lines and reduced the tumor burden in the AML mouse model. Using the quantitative proteomic technique, we discovered a pivotal mechanism that mediates AML cell differentiation, in which autocrine bone morphogenetic protein 6 (BMP6) in MSCs boosted IL-6 secretion and further acted on leukemic cells to trigger differentiation. Furthermore, the activity of the BMP6-IL6 axis was dramatically enhanced by activating vitamin D receptor (VDR) in MSCs. Our data illustrated an effective preactivated approach to reinforcing the antileukemia effect of MSCs, which could serve as an effective therapeutic strategy for AML.

Proteomics for optimizing therapy in acute myeloid leukemia: venetoclax plus hypomethylating agents versus conventional chemotherapy

The use of Hypomethylating agents combined with Venetoclax (VH) for the treatment of Acute Myeloid Leukemia (AML) has greatly improved outcomes in recent years. However not all patients benefit from the VH regimen and a way to rationally select between VH and Conventional Chemotherapy (CC) for individual AML patients is needed. Here, we developed a proteomic-based triaging strategy using Reverse-phase Protein Arrays (RPPA) to optimize therapy selection. We evaluated the expression of 411 proteins in 810 newly diagnosed adult AML patients, identifying 109 prognostic proteins, that divided into five patient expression profiles, which are useful for optimizing therapy selection. Furthermore, using machine learning algorithms, we determined a set of 14 proteins, among those 109, that were able to accurately recommend therapy, making it feasible for clinical application. Next, we identified a group of patients who did not benefit from either VH or CC and proposed target-based approaches to improve outcomes. Finally, we calculated that the clinical use of our proteomic strategy would have led to a change in therapy for 30% of patients, resulting in a 43% improvement in OS, resulting in around 2600 more cures from AML per year in the United States.

Pracinostat combined with azacitidine in newly diagnosed adult acute myeloid leukemia (AML) patients unfit for standard induction chemotherapy: PRIMULA phase III study

Non-intensive therapies such as the hypomethylating agent (HMA) azacitidine (AZA) have been used in patients with AML ineligible for intensive induction chemotherapy (IC) or stem cell transplant due to advanced age, comorbidities, and/or risk factors. However, response rates and survival remain dismal. Pre-clinical studies indicate the epigenetic combination of HMAs and HDAC inhibitors induce re-expression of silenced genes synergistically. The activity of pracinostat, an oral pan-HDAC inhibitor, has been shown in xenograft tumor models of AML and promising efficacy was seen in a Phase 2 study. This Phase 3 study (NCT03151408) evaluated the efficacy/safety of pracinostat administered with AZA in adult patients with newly diagnosed AML ineligible to receive IC. Patients were randomized to either pracinostat plus AZA or placebo/AZA and stratified by cytogenetic risk and ECOG status. As planned, an interim analysis was performed when 232/390 events (deaths) occurred. A total of 406 patients were randomized (203/group) at the time of the analysis. Median overall survival was 9.95 months for both treatment groups (p=0.8275). There was no significant difference between treatments in secondary efficacy endpoints, reflecting a lack of clinical response. This study did not show a benefit of adding pracinostat to AZA in elderly patients unfit for IC.

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.

Mathematical modelling of clonal reduction therapeutic strategies in acute myeloid leukemia

Over the years, the overall survival of older patients diagnosed with acute myeloid leukemia (AML) has not significantly increased. Although standard cytotoxic therapies that rapidly eliminate dividing myeloblasts are used to induce remission, relapse can occur due to surviving therapy-resistant leukemic stem cells (LSCs). Hence, anti-LSC strategies have become a key target to cure AML. We have recently shown that previously approved cardiac glycosides and glucocorticoids target LSC-enriched CD34+ cells in the primary human AML 8227 model with more efficacy than normal hematopoietic stem cells (HSCs). To translate these in vitro findings into humans, we developed a mathematical model of stem cell dynamics that describes the stochastic evolution of LSCs in AML post-standard-of-care. To this, we integrated population pharmacokinetic-pharmacodynamic (PKPD) models to investigate the clonal reduction potential of several promising candidate drugs in comparison to cytarabine, which is commonly used in high doses for consolidation therapy in AML patients. Our results suggest that cardiac glycosides (proscillaridin A, digoxin and ouabain) and glucocorticoids (budesonide and mometasone) reduce the expansion of LSCs through a decrease in their viability. While our model predicts that effective doses of cardiac glycosides are potentially too toxic to use in patients, simulations show the possibility of mometasone to prevent relapse through the glucocorticoid's ability to drastically reduce LSC population size. This work therefore highlights the prospect of these treatments for anti-LSC strategies and underlines the use of quantitative approaches to preclinical drug translation in AML.

Kikuchi disease in acute leukaemia: a distinct clinical syndrome with HLA association

AIMS

To report the clinicopathological features of Kikuchi disease in patients with acute leukaemia, emphasising similarities among cases.

METHODS AND RESULTS

In a cohort of 454 Kikuchi disease patients, we identified three cases of concurrent acute leukaemia. These patients shared similar clinical traits, with Kikuchi disease emerging approximately a month after induction chemotherapy onset, featuring neck-region lymphadenopathy. Notably, two patients were middle-aged, deviating from the typical age distribution of Kikuchi disease. Histologically, these cases aligned with typical Kikuchi disease. Negative immunohistochemical stains (CD34, CD117, ERG, TdT) indicated the absence of extramedullary leukaemic infiltration. Herpes simplex virus immunohistochemical staining was also negative. Significantly, a human leucocyte antigen (HLA) association was observed in these three cases. HLA-B*15:01, C*04:01, and DRB1*04:06 were more prevalent in these patients compared to the general population (compared with three independent control cohorts: Taiwanese Han Chinese (n = 504), Tzu Chi Taiwanese bone marrow donors (n = 364) and Hong Kong Chinese (n = 5266)).

CONCLUSIONS

Our study underscores the unique link between Kikuchi disease and acute leukaemia, characterised by specific features and HLA associations. This underlines Kikuchi disease as a possible differential diagnosis in pertinent clinical scenarios. Furthermore, this syndrome offers insights into postchemotherapy immunology in acute leukaemia, enhancing comprehension.

Metabolic reprogramming regulated by TRAF6 contributes to the leukemia progression

TNF receptor associated factor 6 (TRAF6) is an E3 ubiquitin ligase that has been implicated in myeloid malignancies. Although altered TRAF6 expression is observed in human acute myeloid leukemia (AML), its role in the AML pathogenesis remains elusive. In this study, we showed that the loss of TRAF6 in AML cells significantly impairs leukemic function in vitro and in vivo, indicating its functional importance in AML subsets. Loss of TRAF6 induces metabolic alterations, such as changes in glycolysis, TCA cycle, and nucleic acid metabolism as well as impaired mitochondrial membrane potential and respiratory capacity. In leukemic cells, TRAF6 expression shows a positive correlation with the expression of O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT), which catalyzes the addition of O-GlcNAc to target proteins involved in metabolic regulation. The restoration of growth capacity and metabolic activity in leukemic cells with TRAF6 loss, achieved through either forced expression of OGT or pharmacological inhibition of O-GlcNAcase (OGA) that removes O-GlcNAc, indicates the significant role of O-GlcNAc modification in the TRAF6-related cellular and metabolic dynamics. Our findings highlight the oncogenic function of TRAF6 in leukemia and illuminate the novel TRAF6/OGT/O-GlcNAc axis as a potential regulator of metabolic reprogramming in leukemogenesis.

Emetine induces oxidative stress, cell differentiation and NF-κB inhibition, suppressing AML stem/progenitor cells

Acute myeloid leukemia (AML) is a fatal malignancy of the blood and bone marrow. Leukemic stem cells (LSCs) are a rare subset of leukemic cells that promote the development and progression of AML, and eradication of LSCs is critical for effective control of this disease. Emetine is an FDA-approved antiparasitic drug with antitumor properties; however, little is known about its potential against LSCs. Herein, we explored the antileukemic potential of emetine, focusing on its effects on AML stem/progenitor cells. Emetine exhibited potent cytotoxic activity both in hematologic and solid cancer cells and induced AML cell differentiation. Emetine also inhibited AML stem/progenitor cells, as evidenced by decreased expression of CD34, CD97, CD99, and CD123 in KG-1a cells, indicating anti-AML stem/progenitor cell activities. The administration of emetine at a dosage of 10 mg/kg for two weeks showed no significant toxicity and significantly reduced xenograft leukemic growth in vivo. NF-κB activation was reduced in emetine-treated KG-1a cells, as shown by reduced phospho-NF-κB p65 (S529) and nuclear NF-κB p65. DNA fragmentation, YO-PRO-1 staining, mitochondrial depolarization and increased levels of active caspase-3 and cleaved PARP (Asp214) were detected in emetine-treated KG-1a cells. Moreover, treatment with the pancaspase inhibitor Z-VAD(OMe)-FMK partially prevented the apoptotic cell death induced by emetine. Emetine treatment also increased cellular and mitochondrial reactive oxygen species, and emetine-induced apoptosis in KG-1a cells was partially prevented by the antioxidant N-acetylcysteine, indicating that emetine induces apoptosis, at least in part, by inducing oxidative stress. Overall, these studies indicate that emetine is a novel potential anti-AML agent with promising activity against stem/progenitor cells, encouraging the development of further studies aimed at its clinical application.

Combining 5-azacitidine with the E-selectin antagonist uproleselan is an effective strategy to augment responses in myelodysplasia and acute myeloid leukaemia

The interaction of acute myeloid leukaemic (AML) blasts with the bone marrow (BM) microenvironment is a major determinant governing disease progression and resistance to treatment. The constitutive expression of E-selectin in the vascular compartment of BM, a key endothelial cell factor, directly mediates chemoresistance via E-selectin ligand/receptors. Despite the success of hypomethylating agent (HMA)-containing regimens to induce remissions in older AML patients, the development of primary or secondary resistance is common. We report that following treatment with 5-azacitidine, promoter regions regulating the biosynthesis of the E-selectin ligands, sialyl Lewis X, become further hypomethylated. The resultant upregulation of these gene products, in particular α(1,3)-fucosyltransferase VII (FUT7) and α(2,3)-sialyltransferase IV (ST3GAL4), likely causes functional E-selectin binding. When combined with the E-selectin antagonist uproleselan, the adhesion to E-selectin is reversed and the survival of mice transplanted with AML cells is prolonged. Finally, we present clinical evidence showing that BM myeloid cells from higher risk MDS and AML patients have the potential to bind E-selectin, and these cells are more abundant in 5-azacitidine-non-responsive patients. The collective data provide a strong rationale to evaluate 5-azacitidine in combination with the E-selectin antagonist, uproleselan, in this patient population.

Systems Biology for Drug Target Discovery in Acute Myeloid Leukemia

Combining new therapeutics with all-trans-retinoic acid (ATRA) could improve the efficiency of acute myeloid leukemia (AML) treatment. Modeling the process of ATRA-induced differentiation based on the transcriptomic profile of leukemic cells resulted in the identification of key targets that can be used to increase the therapeutic effect of ATRA. The genome-scale transcriptome analysis revealed the early molecular response to the ATRA treatment of HL-60 cells. In this study, we performed the transcriptomic profiling of HL-60, NB4, and K562 cells exposed to ATRA for 3-72 h. After treatment with ATRA for 3, 12, 24, and 72 h, we found 222, 391, 359, and 1032 differentially expressed genes (DEGs) in HL-60 cells, as well as 641, 1037, 1011, and 1499 DEGs in NB4 cells. We also found 538 and 119 DEGs in K562 cells treated with ATRA for 24 h and 72 h, respectively. Based on experimental transcriptomic data, we performed hierarchical modeling and determined cyclin-dependent kinase 6 (CDK6), tumor necrosis factor alpha (TNF-alpha), and transcriptional repressor CUX1 as the key regulators of the molecular response to the ATRA treatment in HL-60, NB4, and K562 cell lines, respectively. Mapping the data of TMT-based mass-spectrometric profiling on the modeling schemes, we determined CDK6 expression at the proteome level and its down-regulation at the transcriptome and proteome levels in cells treated with ATRA for 72 h. The combination of therapy with a CDK6 inhibitor (palbociclib) and ATRA (tretinoin) could be an alternative approach for the treatment of acute myeloid leukemia (AML).

Unveiling novel insights in acute myeloid leukemia through single-cell RNA sequencing

Acute myeloid leukemia (AML) is a complex and heterogeneous group of aggressive hematopoietic stem cell disease. The presence of diverse and functionally distinct populations of leukemia cells within the same patient's bone marrow or blood poses a significant challenge in diagnosing and treating AML. A substantial proportion of AML patients demonstrate resistance to induction chemotherapy and a grim prognosis upon relapse. The rapid advance in next generation sequencing technologies, such as single-cell RNA-sequencing (scRNA-seq), has revolutionized our understanding of AML pathogenesis by enabling high-resolution interrogation of the cellular heterogeneity in the AML ecosystem, and their transcriptional signatures at a single-cell level. New studies have successfully characterized the inextricably intertwined interactions among AML cells, immune cells and bone marrow microenvironment and their contributions to the AML development, therapeutic resistance and relapse. These findings have deepened and broadened our understanding the complexity and heterogeneity of AML, which are difficult to detect with bulk RNA-seq. This review encapsulates the burgeoning body of knowledge generated through scRNA-seq, providing the novel insights and discoveries it has unveiled in AML biology. Furthermore, we discuss the potential implications of scRNA-seq in therapeutic opportunities, focusing on immunotherapy. Finally, we highlight the current limitations and future direction of scRNA-seq in the field.

NET-related gene signature for predicting AML prognosis

Acute Myeloid Leukemia (AML) is a malignant blood cancer with a high mortality rate. Neutrophil extracellular traps (NETs) influence various tumor outcomes. However, NET-related genes (NRGs) in AML had not yet received much attention. This study focuses on the role of NRGs in AML and their interaction with the immunological microenvironment. The gene expression and clinical data of patients with AML were downloaded from the TCGA-LAML and GEO cohorts. We identified 148 NRGs through the published article. Univariate Cox regression was used to analyze the association of NRGs with overall survival (OS). The least absolute shrinkage and selection operator were utilized to assess the predictive efficacy of NRGs. Kaplan-Meier plots visualized survival estimates. ROC curves assessed the prognostic value of NRG-based features. A nomogram, integrating clinical information and prognostic scores of patients, was constructed using multivariate logistic regression and Cox proportional hazards regression models. Twenty-seven NRGs were found to significantly impact patient OS. Six NRGs-CFTR, ENO1, PARVB, DDIT4, MPO, LDLR-were notable for their strong predictive ability regarding patient survival. The ROC values for 1-, 3-, and 5-year survival rates were 0.794, 0.781, and 0.911, respectively. In the training set (TCGA-LAML), patients in the high NRG risk group showed a poorer prognosis (p < 0.001), which was validated in two external datasets (GSE71014 and GSE106291). The 6-NRG signature and corresponding nomograms exhibit superior predictive accuracy, offering insights for pre-immune response evaluation and guiding future immuno-oncology treatments and drug selection for AML patients.

Chimeric antigen receptor (CAR) modified T Cells in acute myeloid leukemia: limitations and expectations

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy with a poor prognosis despite the advent of novel therapies. Consequently, a major need exists for new therapeutic options, particularly for patients with relapsed/refractory (R/R) AML. In recent years, it has been possible to individualize the treatment of a subgroup of patients, particularly with the emergence of multiple targeted therapies. Nonetheless, a considerable number of patients remain without therapeutic options, and overall prognosis remains poor because of a high rate of disease relapse. In this sense, cellular therapies, especially chimeric antigen receptor (CAR)-T cell therapy, have dramatically shifted the therapeutic options for other hematologic malignancies, such as diffuse large B cell lymphoma and acute lymphoblastic leukemia. In contrast, effectively treating AML with CAR-based immunotherapy poses major biological and clinical challenges, most of them derived from the unmet need to identify target antigens with expression restricted to the AML blast without compromising the viability of the normal hematopoietic stem cell counterpart. Although those limitations have hampered CAR-T cell therapy translation to the clinic, there are several clinical trials where target antigens, such as CD123, CLL-1 or CD33 are being used to treat AML patients showing promising results. Moreover, there are continuing efforts to enhance the specificity and efficacy of CAR-T cell therapy in AML. These endeavors encompass the exploration of novel avenues, including the development of dual CAR-T cells and next-generation CAR-T cells, as well as the utilization of gene editing tools to mitigate off-tumor toxicities. In this review, we will summarize the ongoing clinical studies and the early clinical results reported with CAR-T cells in AML, as well as highlight CAR-T cell limitations and the most recent approaches to overcome these barriers. We will also discuss how and when CAR-T cells should be used in the context of AML.

Efficacy and safety of venetoclax plus hypomethylating agents in relapsed/refractory acute myeloid leukemia: a multicenter real-life experience

Venetoclax (VEN) has been shown to play a synergistic effect in combination with hypomethylating agents (HMAs) in the frontline treatment of acute myeloid leukemia (AML). However, the potential role of this therapy in the relapsed/refractory (R/R) AML setting, still needs to be further unveiled. The aim of the current study was to retrospectively outline the safety profile, response and survival outcomes of R/R AML patients treated with VEN in association with HMAs. Clinical, biological, and molecular data were collected from 57 patients with R/R AML treated with VEN combined with azacitidine or decitabine between 2018 and 2023. The median age of patients was 63 years, 38 (66.7%) received treatment for relapsed disease while 19 (33.3%) for refractory disease, 5 (8.7%) were treated for molecular relapse. A consistent proportion of the cohort was represented by patients with unfavorable prognostic factors such as complex karyotype (36.8%), secondary AML (29.8%), previous exposure to HMAs (38.6%), and relapse after allogeneic stem cell transplant (22.8%). A total of 14 patients achieved CR (24.6%), 3 (5.3%) CRi, 3 (5.3%) MLFS, and 3 (5.3%) PR, accounting for an ORR of 40.4%. The CR/CRi rate was higher in the group treated with azacitidine than in the group treated with decitabine (37.8% vs. 15%). The median OS was 8.2 months, reaching 20.1 months among responding patients. VEN-HMAs treatment allowed to bridge to allogeneic stem cell transplantation 11 (23.9%) of eligible patients, for which a median OS of 19.8 months was shown. On multivariate analysis, ECOG performance status ≥2, complex karyotype and not proceeding to allogeneic stem cell transplantation after therapy with VEN-HMAs were the factors independently associated with shorter OS. Patients treated with the azacitidine rather than the decitabine containing regimen generally displayed a trend toward superior outcomes. The major toxicities were prolonged neutropenia and infections. In conclusion, this study showed how VEN-HMAs could represent an effective salvage therapy in patients with R/R AML, even among some of those patients harboring dismal prognostic features, with a good toxicity profile. Further prospective studies are thus warranted.

Targeting ferroptosis for leukemia therapy: exploring novel strategies from its mechanisms and role in leukemia based on nanotechnology

The latest findings in iron metabolism and the newly uncovered process of ferroptosis have paved the way for new potential strategies in anti-leukemia treatments. In the current project, we reviewed and summarized the current role of nanomedicine in the treatment and diagnosis of leukemia through a comparison made between traditional approaches applied in the treatment and diagnosis of leukemia via the existing investigations about the ferroptosis molecular mechanisms involved in various anti-tumor treatments. The application of nanotechnology and other novel technologies may provide a new direction in ferroptosis-driven leukemia therapies. The article explores the potential of targeting ferroptosis, a new form of regulated cell death, as a new therapeutic strategy for leukemia. It discusses the mechanisms of ferroptosis and its role in leukemia and how nanotechnology can enhance the delivery and efficacy of ferroptosis-inducing agents. The article not only highlights the promise of ferroptosis-targeted therapies and nanotechnology in revolutionizing leukemia treatment, but also calls for further research to overcome challenges and fully realize the clinical potential of this innovative approach. Finally, it discusses the challenges and opportunities in clinical applications of ferroptosis.

Identification of hub genes and potential molecular mechanisms related to drug sensitivity in acute myeloid leukemia based on machine learning

Background: Acute myeloid leukemia (AML) is the most common form of leukemia among adults and is characterized by uncontrolled proliferation and clonal expansion of hematopoietic cells. There has been a significant improvement in the treatment of younger patients, however, prognosis in the elderly AML patients remains poor. Methods: We used computational methods and machine learning (ML) techniques to identify and explore the differential high-risk genes (DHRGs) in AML. The DHRGs were explored through multiple in silico approaches including genomic and functional analysis, survival analysis, immune infiltration, miRNA co-expression and stemness features analyses to reveal their prognostic importance in AML. Furthermore, using different ML algorithms, prognostic models were constructed and validated using the DHRGs. At the end molecular docking studies were performed to identify potential drug candidates targeting the selected DHRGs. Results: We identified a total of 80 DHRGs by comparing the differentially expressed genes derived between AML patients and normal controls and high-risk AML genes identified by Cox regression. Genetic and epigenetic alteration analyses of the DHRGs revealed a significant association of their copy number variations and methylation status with overall survival (OS) of AML patients. Out of the 137 models constructed using different ML algorithms, the combination of Ridge and plsRcox maintained the highest mean C-index and was used to build the final model. When AML patients were classified into low- and high-risk groups based on DHRGs, the low-risk group had significantly longer OS in the AML training and validation cohorts. Furthermore, immune infiltration, miRNA coexpression, stemness feature and hallmark pathway analyses revealed significant differences in the prognosis of the low- and high-risk AML groups. Drug sensitivity and molecular docking studies revealed top 5 drugs, including carboplatin and austocystin-D that may significantly affect the DHRGs in AML. Conclusion: The findings from the current study identified a set of high-risk genes that may be used as prognostic and therapeutic markers for AML patients. In addition, significant use of the ML algorithms in constructing and validating the prognostic models in AML was demonstrated. Although our study used extensive bioinformatics and machine learning methods to identify the hub genes in AML, their experimental validations using knock-out/-in methods would strengthen our findings.

Licochalcone A induces mitochondria-dependent apoptosis and interacts with venetoclax in acute myeloid leukemia

The management of patients with acute myeloid leukemia (AML) remains a challenge because of the complexity and heterogeneity of this malignancy. Despite the recent approval of several novel targeted drugs, resistance seems inevitable, and clinical outcomes are still suboptimal. Increasing evidence supports the use of natural plants as an important source of anti-leukemic therapeutics. Licochalcone A (LCA) is an active flavonoid isolated from the roots of licorice, Glycyrrhiza uralensis Fisch., possessing extensive anti-tumor activities. However, its effects on AML and the underlying mechanisms remain unknown. Here, we showed that LCA decreased the viability of established human AML cell lines in a dose- and time-dependent manner. LCA significantly induced mitochondrial apoptotic cell death, accompanied by the downregulation of MCL-1, upregulation of BIM, truncation of BID, and cleavage of PARP. A prominent decline in the phosphorylation of multiple critical molecules, including AKT, glycogen synthase kinase-3β (GSK3β), ERK, and P38 was observed upon LCA treatment, indicating PI3K and MAPK signals were suppressed. Both transcription and translation of c-Myc were also inhibited by LCA. In addition, LCA enhanced the cytotoxicity of the BCL-2 inhibitor venetoclax. Furthermore, the anti-survival and pro-apoptotic effects were confirmed in primary blasts from 10 patients with de novo AML. Thus, our results expand the applications of LCA, which can be regarded as a valuable agent in treating AML.

Natural products as potential drug treatments for acute promyelocytic leukemia

Acute promyelocytic leukemia (APL), which was once considered one of the deadliest types of leukemia, has become a curable malignancy since the introduction of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) as clinical treatments. ATO, which has become the first-line therapeutic agent for APL, is derived from the natural mineral product arsenic, exemplifying an important role of natural products in the treatment of APL. Many other natural products, ranging from small-molecule compounds to herbal extracts, have also demonstrated great potential for the treatment and adjuvant therapy of APL. In this review, we summarize the natural products and representative components that have demonstrated biological activity for the treatment of APL. We also discuss future directions in better exploring their medicinal value, which may provide a reference for subsequent new drug development and combination therapy programs.

Flow cytometry-based measurable residual disease (MRD) analysis identifies AML patients who may benefit from allogeneic hematopoietic stem cell transplantation

Measurable residual disease (MRD) monitoring independently predicts long-term outcomes in patients with acute myeloid leukemia (AML). Of the various modalities available, multiparameter flow cytometry-based MRD analysis is widely used and relevant for patients without molecular targets. In the transplant (HCT) setting, the presence of MRD pre-HCT is associated with adverse outcomes. MRD-negative remission status pre-HCT was also associated with longer overall (OS) and progression-free survival and a lower risk of relapse. We hypothesize that the combination of disease risk and MRD at the time of first complete remission (CR1) could identify patients according to the benefit gained from HCT, especially for intermediate-risk patients. We performed a retrospective analysis comparing the outcomes of HCT versus non-HCT therapies based on MRD status in AML patients who achieved CR1. Time-dependent analysis was applied considering time-to-HCT as a time-dependent covariate and compared HCT versus non-HCT outcomes according to MRD status at CR1. Among 336 patients assessed at CR1, 35.1% were MRD positive (MRDpos) post-induction. MRDpos patients benefitted from HCT with improved OS and relapse-free survival (RFS), while no benefit was observed in MRDneg patients. In adverse-risk patients, HCT improved OS (HR for OS 0.55; p = 0.05). In intermediate-risk patients, HCT benefit was not significant for OS and RFS. Intermediate-risk MRDpos patients were found to have benefit from HCT with improved OS (HR 0.45, p = 0.04), RFS (HR 0.46, p = 0.02), and CIR (HR 0.41, p = 0.02). Our data underscore the benefit of HCT in adverse risk and MRDpos intermediate-risk AML patients.

Clinical outcomes of hypomethylating agents plus Venetoclax as frontline treatment in patients 75 years and older with acute myeloid leukemia: Real-world data from eight US academic centers

Venetoclax (VEN) combined with hypomethylating agents (HMAs) is the standard of care for the treatment of patients with newly diagnosed acute myeloid leukemia (AML) unfit for intensive chemotherapy. To date, real-world data published on HMAs plus VEN have been either single-center studies or using community-based electronic databases with limited details on mutational landscape, tolerability, and treatment patterns in elderly patients. Therefore, we conducted a multicenter retrospective study to assess the real-world experience of 204 elderly patients (≥75 years) with newly diagnosed AML treated with HMAs plus VEN from eight academic centers in the United States. Overall, 64 patients achieved complete remission (CR; 38%) and 43 CR with incomplete count recovery (CRi; 26%) for a CR/CRi rate of 64%, with a median duration of response of 14.2 months (95% CI: 9.43, 22.1). Among responders, 63 patients relapsed (59%) with median overall survival (OS) after relapse of 3.4 months (95% CI, 2.4, 6.7). Median OS for the entire population was 9.5 months (95% CI, 7.85-13.5), with OS significantly worse among patients with TP53-mutated AML (2.5 months) and improved in patients harboring NPM1, IDH1, and IDH2 mutations (13.5, 18.3, and 21.1 months, respectively). The 30-day and 60-day mortality rates were 9% and 19%, respectively. In conclusion, HMAs plus VEN yielded high response rates in elderly patients with newly diagnosed AML. The median OS was inferior to that reported in the VIALE-A trial. Outcomes are dismal after failure of HMAs plus VEN, representing an area of urgent unmet clinical need.

Synergistic cytotoxicity of decitabine and YM155 in leukemia cells through upregulation of SLC35F2 and suppression of MCL1 and survivin expression

The hypomethylation agent decitabine (DAC), in combination with other apoptosis inducers, is considered a potential modality for cancer treatment. We investigated the mechanism underlying the combined cytotoxicity of DAC and YM155 in acute myeloid leukemia (AML) cells because of increasing evidence that YM155 induces apoptosis in cancer cells. Co-administration of DAC and YM155 resulted in synergistic cytotoxicity in AML U937 cells, which was characterized by the induction of apoptosis, NOXA-dependent degradation of MCL1 and survivin, and depolarization of mitochondria. Restoration of MCL1 or survivin expression attenuated DAC/YM155-induced U937 cell death. DAC initiated AKT and p38 MAPK phosphorylation in a Ca2+/ROS-dependent manner, thereby promoting autophagy-mediated degradation of β-TrCP mRNA, leading to increased Sp1 expression. DAC-induced Sp1 expression associated with Ten-eleven-translocation (TET) dioxygenases and p300 was used to upregulate the expression of SLC35F2. Simultaneously, the activation of p38 MAPK induced by DAC, promoted CREB-mediated NOXA expression, resulting in survivin and MCL1 degradation. The synergistic cytotoxicity of DAC and YM155 in U937 cells was dependent on elevated SLC35F2 expression. Additionally, YM155 facilitated DAC-induced degradation of MCL1 and survivin. A similar mechanism explained DAC/YM155-mediated cytotoxicity in AML HL-60 cells. Our data demonstrated that the synergistic cytotoxicity of DAC and YM155 in AML cell lines U937 and HL-60 is dependent on AKT- and p38 MAPK-mediated upregulation of SLC35F2 and p38 MAPK-mediated degradation of survivin and MCL1. This indicates that a treatment regimen that amalgamates YM155 and DAC may be beneficial for AML.

Manufacturing of primary CAR-NK cells in an automated system for the treatment of acute myeloid leukemia

Acute myeloid leukemia (AML) still constitutes a dreadful disease with limited therapeutic options. Chimeric antigen receptor (CAR)-modified T cells struggle to target AML partly due to a lack of true AML-exclusive antigens and heterogeneity of the disease. Natural killer (NK) cells possess a high intrinsic killing capacity against AML and might be well suited for the treatment of this disease. However, the generation of primary CAR-NK cells can be difficult and time consuming. Therefore, robust systems for the generation of high numbers of CAR-NK cells under GMP conditions are required. Here we report on the automated generation of high numbers of primary CD33-targeting CAR-NK cells using the CliniMACS Prodigy® platform. Automated-produced CD33-CAR-NK cells showed similar phenotype and cytotoxicity compared to small-scale-produced CD33-CAR-NK cells in vitro and were able to strongly reduce leukemic burden in an OCI-AML2 NSG-SGM3 xenograft mouse model in vivo following a cross-site shipment of the cell product. This technology might be well suited for the generation of primary CAR-modified NK cells for a broad range of targets and could facilitate clinical transition.

Bortezomib suppresses acute myelogenous leukaemia stem-like KG-1a cells via NF-κB inhibition and the induction of oxidative stress

Acute myelogenous leukaemia (AML) originates and is maintained by leukaemic stem cells (LSCs) that are inherently resistant to antiproliferative therapies, indicating that a critical strategy for overcoming chemoresistance in AML therapy is to eradicate LSCs. In this work, we investigated the anti-AML activity of bortezomib (BTZ), emphasizing its anti-LSC potential, using KG-1a cells, an AML cell line with stem-like properties. BTZ presented potent cytotoxicity to both solid and haematological malignancy cells and reduced the stem-like features of KG-1a cells, as observed by the reduction in CD34- and CD123-positive cells. A reduction in NF-κB p65 nuclear staining was observed in BTZ-treated KG-1a cells, in addition to upregulation of the NF-κB inhibitor gene NFΚBIB. BTZ-induced DNA fragmentation, nuclear condensation, cell shrinkage and loss of transmembrane mitochondrial potential along with an increase in active caspase-3 and cleaved PARP-(Asp 214) level in KG-1a cells. Furthermore, BTZ-induced cell death was partially prevented by pretreatment with the pancaspase inhibitor Z-VAD-(OMe)-FMK, indicating that BTZ induces caspase-mediated apoptosis. BTZ also increased mitochondrial superoxide levels in KG-1a cells, and BTZ-induced apoptosis was partially prevented by pretreatment with the antioxidant N-acetylcysteine, indicating that BTZ induces oxidative stress-mediated apoptosis in KG-1a cells. At a dosage of 0.1 mg/kg every other day for 2 weeks, BTZ significantly reduced the percentage of hCD45-positive cells in the bone marrow and peripheral blood of NSG mice engrafted with KG-1a cells with tolerable toxicity. Taken together, these data indicate that the anti-LSC potential of BTZ appears to be an important strategy for AML treatment.

STING-activating cyclic dinucleotide-manganese nanoparticles evoke robust immunity against acute myeloid leukemia

Acute myeloid leukemia (AML) is one of the most common types of leukemia in adults with a 5-year survival rate of 30.5%. These poor patient outcomes are attributed to tumor relapse, stemming from ineffective innate immune activation, T cell tolerance, and a lack of immunological memory. Thus, new strategies are needed to activate innate and effector immune cells and evoke long-term immunity against AML. One approach to address these issues is through Stimulator of Interferon Genes (STING) pathway activation, which produces Type I Interferons (Type I IFN) critical for innate and adaptive immune activation. Here, we report that systemic immunotherapy with a lipid-based nanoparticle platform (CMP) carrying Mn2+ and STING agonist c-di-AMP (CDA) exhibited robust anti-tumor efficacy in a mouse model of disseminated AML. Moreover, CMP immunotherapy combined with immune checkpoint blockade against cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4) elicited robust innate and adaptive immune activation with enhanced cytotoxic potential against AML, leading to extended animal survival after re-challenge with AML. Overall, this CMP combination immunotherapy may be a promising approach against AML and other disseminated cancer.

Novel Therapeutic Targets in Acute Myeloid Leukemia (AML)

PURPOSE OF REVIEW

This review seeks to identify and describe novel genetic and protein targets and their associated therapeutics currently being used or studied in the treatment of acute myeloid leukemia (AML).

RECENT FINDINGS

Over the course of the last 5-6 years, several targeted therapies have been approved by the FDA, for the treatment of both newly diagnosed as well as relapsed/refractory AML. These novel therapeutics, as well as several others currently under investigation, have demonstrated activity in AML and have improved outcomes for many patients. Patient outcomes in AML have slowly improved over time, though for many patients, particularly elderly patients or those with relapsed/refractory disease, mortality remains very high. With the identification of several molecular/genetic drivers and protein targets and development of therapeutics which leverage those mechanisms to target leukemic cells, outcomes for patients with AML have improved and continue to improve significantly.

Nanoparticle-encapsulated retinoic acid for the modulation of bone marrow hematopoietic stem cell niche

More effective approaches are needed in the treatment of blood cancers, in particular acute myeloid leukemia (AML), that are able to eliminate resistant leukemia stem cells (LSCs) at the bone marrow (BM), after a chemotherapy session, and then enhance hematopoietic stem cell (HSC) engraftment for the re-establishment of the HSC compartment. Here, we investigate whether light-activatable nanoparticles (NPs) encapsulating all-trans-retinoic acid (RA+NPs) could solve both problems. Our in vitro results show that mouse AML cells transfected with RA+NPs differentiate towards antitumoral M1 macrophages through RIG.1 and OASL gene expression. Our in vivo results further show that mouse AML cells transfected with RA+NPs home at the BM after transplantation in an AML mouse model. The photo-disassembly of the NPs within the grafted cells by a blue laser enables their differentiation towards a macrophage lineage. This macrophage activation seems to have systemic anti-leukemic effect within the BM, with a significant reduction of leukemic cells in all BM compartments, of animals treated with RA+NPs, when compared with animals treated with empty NPs. In a separate group of experiments, we show for the first time that normal HSCs transfected with RA+NPs show superior engraftment at the BM niche than cells without treatment or treated with empty NPs. This is the first time that the activity of RA is tested in terms of long-term hematopoietic reconstitution after transplant using an in situ activation approach without any exogenous priming or genetic conditioning of the transplanted cells. Overall, the approach documented here has the potential to improve consolidation therapy in AML since it allows a dual intervention in the BM niche: to tackle resistant leukemia and improve HSC engraftment at the same time.

Recent Advances in Material Technology for Leukemia Treatments

Leukemia is a widespread hematological malignancy characterized by an elevated white blood cell count in both the blood and the bone marrow. Despite notable advancements in leukemia intervention in the clinic, a large proportion of patients, especially acute leukemia patients, fail to achieve long-term remission or complete remission following treatment. Therefore, leukemia therapy necessitates optimization to meet the treatment requirements. In recent years, a multitude of materials have undergone rigorous study to serve as delivery vectors or direct intervention agents to bolster the effectiveness of leukemia therapy. These materials include liposomes, protein-based materials, polymeric materials, cell-derived materials, and inorganic materials. They possess unique characteristics and are applied in a broad array of therapeutic modalities, including chemotherapy, gene therapy, immunotherapy, radiotherapy, hematopoietic stem cell transplantation, and other evolving treatments. Here, an overview of these materials is presented, describing their physicochemical properties, their role in leukemia treatment, and the challenges they face in the context of clinical translation. This review inspires researchers to further develop various materials that can be used to augment the efficacy of multiple therapeutic modalities for novel applications in leukemia treatment.

The comprehensive landscape of prognosis, immunity, and function of the GLI family by pan-cancer and single-cell analysis

The Hedgehog (Hh) signaling pathway has been implicated in the pathogenesis of various cancers. However, the roles of the downstream GLI family (GLI1, GLI2, and GLI3) in tumorigenesis remain elusive. This study aimed to unravel the genetic alterations of GLI1/2/3 in cancer and their association with the immune microenvironment and related signaling pathways. Firstly, we evaluated the expression profiles of GLI1/2/3 in different cancer types, analyzed their prognostic and predictive values, and assessed their correlation with tumor-infiltrating immune cells. Secondly, we explored the relationships between GLI1/2/3 and genetic mutations, epigenetic modifications, and clinically relevant drugs. Finally, we performed enrichment analysis to decipher the underlying mechanisms of GLI1/2/3 in cancer initiation and progression. Our results revealed that the expression levels of GLI1/2/3 were positively correlated in most cancer tissues, suggesting a cooperative role of these factors in tumorigenesis. We also identified tissue-specific expression patterns of GLI1/2/3, which may reflect the distinct functions of these factors in different cell types. Furthermore, GLI1/2/3 expression displayed significant associations with poor prognosis in several cancers, indicating their potential as prognostic biomarkers and therapeutic targets. Importantly, we found that GLI1/2/3 modulated the immune microenvironment by regulating the recruitment, activation, and polarization of cancer-associated fibroblasts, endothelial cells, and macrophages. Additionally, functional enrichment analyses indicated that GLI1/2/3 are involved in the regulation of epithelial-mesenchymal transition (EMT). Together, our findings shed new light on the roles of GLI1/2/3 in tumorigenesis and provide a potential basis for the development of novel therapeutic strategies targeting GLI-mediated signaling pathways in cancer.

Sirtuin 5 regulates acute myeloid leukemia cell viability and apoptosis by succinylation modification of glycine decarboxylase

Acute myeloid leukemia (AML) is a blood system malignancy where sirtuin 5 (SIRT5) is abnormally expressed in AML cell lines. This study aimed to investigate the SIRT5 effects on the viability and apoptosis of AML cell lines. The mRNA and protein expression levels of succinylation regulatory enzyme in clinical samples and AML cell lines were detected by real-time quantitative polymerase chain reaction and western blotting while cell viability was measured using cell counting kit-8 assay. The apoptosis rate was assessed with flow cytometry. The interaction between SIRT5 and glycine decarboxylase (GLDC) was determined by co-immunoprecipitation and immunofluorescence staining techniques. Results indicated higher mRNA and protein expression levels of SIRT5 in clinical AML samples of AML than in normal subjects. Similarly, cell viability was inhibited, and apoptosis was promoted by downregulating SIRT5, in addition to inhibition of SIRT5-mediated GLDC succinylation. Moreover, rescue experiment results showed that GLDC reversed the effects of SIRT5 knockdown on cell viability and apoptosis. These results, in combination with SIRT5 and GLDC interactions, suggested that SIRT5 was involved in mediating AML development through GLDC succinylation. SIRT5 inhibits GLDC succinylation to promote viability and inhibit apoptosis of AML cells, suggesting that SIRT5 encourages the development of AML.

Ex vivo discovery of synergistic drug combinations for hematologic malignancies

Combination therapies have improved outcomes for patients with acute myeloid leukemia (AML). However, these patients still have poor overall survival. Although many combination therapies are identified with high-throughput screening (HTS), these approaches are constrained to disease models that can be grown in large volumes (e.g., immortalized cell lines), which have limited translational utility. To identify more effective and personalized treatments, we need better strategies for screening and exploring potential combination therapies. Our objective was to develop an HTS platform for identifying effective combination therapies with highly translatable ex vivo disease models that use size-limited, primary samples from patients with leukemia (AML and myelodysplastic syndrome). We developed a system, ComboFlow, that comprises three main components: MiniFlow, ComboPooler, and AutoGater. MiniFlow conducts ex vivo drug screening with a miniaturized flow-cytometry assay that uses minimal amounts of patient sample to maximize throughput. ComboPooler incorporates computational methods to design efficient screens of pooled drug combinations. AutoGater is an automated gating classifier for flow cytometry that uses machine learning to rapidly analyze the large datasets generated by the assay. We used ComboFlow to efficiently screen more than 3000 drug combinations across 20 patient samples using only 6 million cells per patient sample. In this screen, ComboFlow identified the known synergistic combination of bortezomib and panobinostat. ComboFlow also identified a novel drug combination, dactinomycin and fludarabine, that synergistically killed leukemic cells in 35 % of AML samples. This combination also had limited effects in normal, hematopoietic progenitors. In conclusion, ComboFlow enables exploration of massive landscapes of drug combinations that were previously inaccessible in ex vivo models. We envision that ComboFlow can be used to discover more effective and personalized combination therapies for cancers amenable to ex vivo models.

CD8 + T cell-based molecular subtypes with heterogeneous immune landscapes and clinical significance in acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy. Although high-dose chemotherapy is the primary treatment option, it cannot cure the disease, and new approaches need to be developed. The tumor microenvironment (TME) plays a crucial role in tumor biology and immunotherapy. CD8 + T cells are the main anti-tumor immune effector cells, and it is essential to understand their relationship with the TME and the clinicopathological characteristics of AML.

METHODS

In this study, we conducted a systematic analysis of CD8 + T cell infiltration through multi-omics data and identified molecular subtypes with significant differences in CD8 + T cell infiltration and prognosis. We aimed to provide a comprehensive evaluation of the pathological factors affecting the prognosis of AML patients and to offer theoretical support for the precise treatment of AML.

RESULTS

Our results indicate that CD8 + T cell infiltration is accompanied by immunosuppression, and that there are two molecular subtypes, with the C2 subtype having a significantly worse prognosis than the C1 subtype, as well as less CD8 + T cell infiltration. We developed a signature to distinguish molecular subtypes using multiple machine learning algorithms and validated the prognostic predictive power of molecular subtypes in nine AML cohorts including 2059 AML patients. Our findings suggest that there are different immunosuppressive characteristics between the two subtypes. The C1 subtype has up-regulated expression of immune checkpoints such as CTLA4, PD-1, LAG3, and TIGITD, while the C2 subtype infiltrates more immunosuppressive cells such as Tregs and M2 macrophages. The C1 subtype is more responsive to anti-PD-1 immunotherapy and induction chemotherapy, as well as having higher immune and cancer-promoting variant-related pathway activity. Patients with the C2 subtype had a higher FLT3 mutation rate, higher WBC counts, and a higher percentage of blasts, as indicated by increased activity of signaling pathways involved in energy metabolism and cell proliferation. Analysis of data from ex vivo AML cell drug assays has identified a group of drugs that differ in therapeutic sensitivity between molecular subtypes.

CONCLUSIONS

Our results suggest that the molecular subtypes we constructed have potential application value in the prognosis evaluation and treatment guidance of AML patients.

DNAJC10 maintains survival and self-renewal of leukemia stem cells through PERK branch of the unfolded protein response

Leukemia stem cells (LSC) require frequent adaptation to maintain their self-renewal ability in the face of longer exposure to cell-intrinsic and cell-extrinsic stresses. However, the mechanisms by which LSC maintain their leukemogenic activities, and how individual LSC respond to stress, remain poorly understood. Here, we found that DNAJC10, a member of HSP40 family, was frequently up-regulated in various types of acute myeloid leukemia (AML) and in LSC-enriched cells. Deficiency of DNAJC10 leads to a dramatic increase in the apoptosis of both human leukemia cell lines and LSC-enriched populations. Although DNAJC10 is not required for normal hematopoiesis, deficiency of Dnajc10 significantly abrogated AML development and suppressed self-renewal of LSC in the MLL-AF9-induced murine leukemia model. Mechanistically, inhibition of DNAJC10 specifically induces endoplasmic reticulum stress and promotes activation of PERK-EIF2α-ATF4 branch of unfolded protein response (UPR). Blocking PERK by GSK2606414 (PERKi) or shRNA rescued the loss of function of DNAJC10 both in vitro and in vivo. Importantly, deficiency of DNAJC10 increased sensitivity of AML cells to daunorubicin (DNR) and cytarabine (Ara-C). These data revealed that DNAJC10 functions as an oncogene in MLL-AF9-induced AML via regulation of the PERK branch of the UPR. DNAJC10 may be an ideal therapeutic target for eliminating LSC, and improving the effectiveness of DNR and Ara-C.

Discovery of 5-trifluoromethyl-2-aminopyrimidine derivatives as potent dual inhibitors of FLT3 and CHK1

Here, we discover an FLT3/CHK1 dual inhibitor (30) that exhibits excellent kinase potency and antiproliferative activity against MV4-11 cells. Simultaneously, 30 possesses high selectivity over c-Kit enzyme and low hERG inhibitory ability. Compound 30, meanwhile, overcomes varied resistance in BaF3 cell lines carrying FLT3-TKD and FLT3-ITD mutations. Moreover, 30 demonstrates favorable oral PK properties and kinase selectivity. These conclusions support that compound 30 may be a promising potential FLT3/CHK1 dual agent for further development.