Novel therapy in Acute myeloid leukemia (AML): moving toward targeted approaches

Acquired Multidrug Resistance in AML Is Caused by Low Apoptotic Priming in Relapsed Myeloblasts

In many cancers, mortality is associated with the emergence of relapse with multidrug resistance (MDR). Thus far, the investigation of cancer relapse mechanisms has largely focused on acquired genetic mutations. Using acute myeloid leukemia (AML) patient-derived xenografts (PDX), we systematically elucidated a basis of MDR and identified drug sensitivity in relapsed AML. We derived pharmacologic sensitivity for 22 AML PDX models using dynamic BH3 profiling (DBP), together with genomics and transcriptomics. Using in vivo acquired resistant PDXs, we found that resistance to unrelated, narrowly targeted agents in distinct PDXs was accompanied by broad resistance to drugs with disparate mechanisms. Moreover, baseline mitochondrial apoptotic priming was consistently reduced regardless of the class of drug-inducing selection. By applying DBP, we identified drugs showing effective in vivo activity in resistant models. This study implies evasion of apoptosis drives drug resistance and demonstrates the feasibility of the DBP approach to identify active drugs for patients with relapsed AML.

SIGNIFICANCE

Acquired resistance to targeted therapy remains challenging in AML. We found that reduction in mitochondrial priming and common transcriptomic signatures was a conserved mechanism of acquired resistance across different drug classes in vivo. Drugs active in vivo can be identified even in the multidrug resistant state by DBP.

Successful use of Palbociclib combined with Venetoclax and Azacitidine in an adult with refractory/relapsed therapy-related acute myeloid leukemia

BACKGROUND

Therapy-related acute myeloid leukemia (t-AML) is considered high risk as it related to prior exposure to cytotoxic chemotherapy agents for solid tumors or hematologic malignancies. Compared with de novo AML, t-AML is associated with lower remission rates, inferior overall survival (OS) and higher relapse rates. Many efforts have been devoted to improving the overall but with limited success, and novel strategy is thus highly needed.

CASE DESCRIPTION

We reported one patient with refractory/relapsed t-AML was successfully treated with Palbociclib combined with Venetoclax and Azacytidine (AZA). In this case, a 47-year-old patient with t-AML recurred during Venetoclax in combination with AZA therapy. However, the patient achieved morphological, immunophenotypic and molecular complete remission again after Palbociclib combined with Venetoclax and AZA.

CONCLUSIONS

Although only one successful case is presented here, three-drug combination regimens should be considered as another treatment option for t-AML in the future.

Development and validation of a cuproptosis-related prognostic model for acute myeloid leukemia patients using machine learning with stacking

Our objective is to develop a prognostic model focused on cuproptosis, aimed at predicting overall survival (OS) outcomes among Acute myeloid leukemia (AML) patients. The model utilized machine learning algorithms incorporating stacking. The GSE37642 dataset was used as the training data, and the GSE12417 and TCGA-LAML cohorts were used as the validation data. Stacking was used to merge the three prediction models, subsequently using a random survival forests algorithm to refit the final model using the stacking linear predictor and clinical factors. The prediction model, featuring stacking linear predictor and clinical factors, achieved AUC values of 0.840, 0.876 and 0.892 at 1, 2 and 3 years within the GSE37642 dataset. In external validation dataset, the corresponding AUCs were 0.741, 0.754 and 0.783. The predictive performance of the model in the external dataset surpasses that of the model simply incorporates all predictors. Additionally, the final model exhibited good calibration accuracy. In conclusion, our findings indicate that the novel prediction model refines the prognostic prediction for AML patients, while the stacking strategy displays potential for model integration.

PD-1H/VISTA mediates immune evasion in acute myeloid leukemia

Acute myeloid leukemia (AML) presents a pressing medical need in that it is largely resistant to standard chemotherapy as well as modern therapeutics, such as targeted therapy and immunotherapy, including anti-programmed cell death protein (anti-PD) therapy. We demonstrate that programmed death-1 homolog (PD-1H), an immune coinhibitory molecule, is highly expressed in blasts from the bone marrow of AML patients, while normal myeloid cell subsets and T cells express PD-1H. In studies employing syngeneic and humanized AML mouse models, overexpression of PD-1H promoted the growth of AML cells, mainly by evading T cell-mediated immune responses. Importantly, ablation of AML cell-surface PD-1H by antibody blockade or genetic knockout significantly inhibited AML progression by promoting T cell activity. In addition, the genetic deletion of PD-1H from host normal myeloid cells inhibited AML progression, and the combination of PD-1H blockade with anti-PD therapy conferred a synergistic antileukemia effect. Our findings provide the basis for PD-1H as a potential therapeutic target for treating human AML.

TIM-3/Galectin-9 interaction and glutamine metabolism in AML cell lines, HL-60 and THP-1

BACKGROUND

T cell immunoglobulin and mucin-domain containing-3 (TIM-3) is a cell surface molecule that was first discovered on T cells. However, recent studies revealed that it is also highly expressed in acute myeloid leukemia (AML) cells and it is related to AML progression. As, Glutamine appears to play a prominent role in malignant tumor progression, especially in their myeloid group, therefore, in this study we aimed to evaluate the relation between TIM-3/Galectin-9 axis and glutamine metabolism in two types of AML cell lines, HL-60 and THP-1.

METHODS

Cell lines were cultured in RPMI 1640 which supplemented with 10% FBS and 1% antibiotics. 24, 48, and 72 h after addition of recombinant Galectin-9 (Gal-9), RT-qPCR analysis, RP-HPLC and gas chromatography techniques were performed to evaluate the expression of glutaminase (GLS), glutamate dehydrogenase (GDH) enzymes, concentration of metabolites; Glutamate (Glu) and alpha-ketoglutarate (α-KG) in glutaminolysis pathway, respectively. Western blotting and MTT assay were used to detect expression of mammalian target of rapamycin complex (mTORC) as signaling factor, GLS protein and cell proliferation rate, respectively.

RESULTS

The most mRNA expression of GLS and GDH in HL-60 cells was seen at 72 h after Gal-9 treatment (p = 0.001, p = 0.0001) and in THP-1 cell line was observed at 24 h after Gal-9 addition (p = 0.001, p = 0.0001). The most mTORC and GLS protein expression in HL-60 and THP-1 cells was observed at 72 and 24 h after Gal-9 treatment (p = 0.0001), respectively. MTT assay revealed that Gal-9 could promote cell proliferation rate in both cell lines (p = 0.001). Glu concentration in HL-60 and α-KG concentration in both HL-60 (p = 0.03) and THP-1 (p = 0.0001) cell lines had a decreasing trend. But, Glu concentration had an increasing trend in THP-1 cell line (p = 0.0001).

CONCLUSION

Taken together, this study suggests TIM-3/Gal-9 interaction could promote glutamine metabolism in HL-60 and THP-1 cells and resulting in AML development.

HDAC11 mediates the ubiquitin-dependent degradation of p53 and inhibits the anti-leukemia effect of PD0166285

Cytarabine-resistant acute myeloid leukemia (AML) is a common phenomenon, necessitating the search for new chemotherapeutics. WEE1 participates in cell cycle checkpoint signaling and inhibitors targeting WEE1 (WEE1i) constitute a potential novel strategy for AML treatment. HDAC (histone deacetylase) inhibitors have been shown to enhance the anti-tumor effects of WEE1i but molecular mechanisms of HDAC remain poorly characterized. In this study, the WEE1 inhibitor PD0166285 showed a relatively good anti-leukemia effect. Notably, PD0166285 can arise the expression of HDAC11 which was negatively correlated with survival of AML patients. Moreover, HDAC11 can reduced the anti-tumor effect of PD0166285 through an effect on p53 stability and the changes in phosphorylation levels of MAPK pathways. Overall, the cell cycle inhibitor, PD0166285, is a potential chemotherapeutic drug for AML. These fundings contribute to a functional understanding of HDAC11 in AML.

Acute myeloid leukemia: from NGS, through scRNA-seq, to CAR-T. dissect cancer heterogeneity and tailor the treatment

Acute myeloid leukemia (AML) is a malignant blood cancer with marked cellular heterogeneity due to altered maturation and differentiation of myeloid blasts, the possible causes of which are transcriptional or epigenetic alterations, impaired apoptosis, and excessive cell proliferation. This neoplasm has a high rate of resistance to anticancer therapies and thus a high risk of relapse and mortality because of both the biological diversity of the patient and intratumoral heterogeneity due to the acquisition of new somatic changes. For more than 40 years, the old gold standard "one size fits all" treatment approach included intensive chemotherapy treatment with anthracyclines and cytarabine.The manuscript first traces the evolution of the understanding of the pathology from the 1970s to the present. The enormous strides made in its categorization prove to be crucial for risk stratification, enabling an increasingly personalized diagnosis and treatment approach.Subsequently, we highlight how, over the past 15 years, technological advances enabling single cell RNA sequencing and T-cell modification based on the genomic tools are affecting the classification and treatment of AML. At the dawn of the new millennium, the advent of high-throughput next-generation sequencing technologies has enabled the profiling of patients evidencing different facets of the same disease, stratifying risk, and identifying new possible therapeutic targets that have subsequently been validated. Currently, the possibility of investigating tumor heterogeneity at the single cell level, profiling the tumor at the time of diagnosis or after treatments exist. This would allow the identification of underrepresented cellular subclones or clones resistant to therapeutic approaches and thus responsible for post-treatment relapse that would otherwise be difficult to detect with bulk investigations on the tumor biopsy. Single-cell investigation will then allow even greater personalization of therapy to the genetic and transcriptional profile of the tumor, saving valuable time and dangerous side effects. The era of personalized medicine will take a huge step forward through the disclosure of each individual piece of the complex puzzle that is cancer pathology, to implement a "tailored" therapeutic approach based also on engineered CAR-T cells.

Molecular subtyping of acute myeloid leukemia through ferroptosis signatures predicts prognosis and deciphers the immune microenvironment

Acute myeloid leukemia (AML) is one of the most aggressive hematological malignancies with a low 5-year survival rate and high rate of relapse. Developing more efficient therapies is an urgent need for AML treatment. Accumulating evidence showed that ferroptosis, an iron-dependent form of programmed cell death, is closely correlated with cancer initiation and clinical outcome through reshaping the tumor microenvironment. However, understanding of AML heterogeneity based on extensive profiling of ferroptosis signatures remains to be investigated yet. Herein, five independent AML transcriptomic datasets (TCGA-AML, GSE37642, GSE12417, GSE10358, and GSE106291) were obtained from the GEO and TCGA databases. Then, we identified two ferroptosis-related molecular subtypes (C1 and C2) with distinct prognosis and tumor immune microenvironment (TIME) by consensus clustering. Patients in the C1 subtype were associated with favorable clinical outcomes and increased cytotoxic immune cell infiltration, including CD8+/central memory T cells, natural killer (NK) cells, and non-regulatory CD4+ T cells while showing decreased suppressive immune subsets such as M2 macrophages, neutrophils, and monocytes. Functional enrichment analysis of differentially expressed genes (DEGs) implied that cell activation involved in immune response, leukocyte cell-cell adhesion and migration, and cytokine production were the main biological processes. Phagosome, antigen processing and presentation, cytokine-cytokine receptor interaction, B-cell receptor, and chemokine were identified as the major pathways. To seize the distinct landscape in C1 vs. C2 subtypes, a 5-gene prognostic signature (LSP1, IL1R2, MPO, CRIP1, and SLC24A3) was developed using LASSO Cox stepwise regression analysis and further validated in independent AML cohorts. Patients were divided into high- and low-risk groups, and decreased survival rates were observed in high- vs. low-risk groups. The TIME between high- and low-risk groups has a similar scenery in C1 vs. C2 subtypes. Single-cell-level analysis verified that LSP1 and CRIP1 were upregulated in AML and exhausted CD8+ T cells. Dual targeting of these two markers might present a promising immunotherapeutic for AML. In addition, potential effective chemical drugs for AML were predicted. Thus, we concluded that molecular subtyping using ferroptosis signatures could characterize the TIME and provide implications for monitoring clinical outcomes and predicting novel therapies.

Discovery of Small-Molecule TIM-3 Inhibitors for Acute Myeloid Leukemia Using Pharmacophore-Based Virtual Screening

T-cell immunoglobulin and mucin domain 3 (TIM-3) is a negative immune checkpoint that represents a promising target for cancer immunotherapy. Although encouraging results have been observed for TIM-3 inhibition in the context of acute myeloid leukemia (AML), targeting TIM-3 is currently restricted to monoclonal antibodies (mAbs). To fill this gap, we implemented a pharmacophore-based screening approach to identify small-molecule TIM-3 inhibitors. Our approach resulted in the identification of hit compounds with TIM-3 binding affinity. Subsequently, we used the structure-activity relationship (SAR) by a catalog approach to identify compound A-41 with submicromolar TIM-3 binding affinity. Remarkably, A-41 demonstrated the ability to block TIM-3 interactions with key ligands and inhibited the immunosuppressive function of TIM-3 using an in vitro coculture assay. This work will pave the way for future drug discovery efforts aiming at the development of small-molecule inhibitors TIM-3 for AML.

Plant-derived extracts and metabolic modulation in leukemia: a promising approach to overcome treatment resistance

Leukemic cells acquire complex and often multifactorial mechanisms of resistance to treatment, including various metabolic alterations. Although the use of metabolic modulators has been proposed for several decades, their use in clinical practice has not been established. Natural products, the so-called botanical drugs, are capable of regulating tumor metabolism, particularly in hematopoietic tumors, which could partly explain the biological activity attributed to them for a long time. This review addresses the most recent findings relating to metabolic reprogramming-Mainly in the glycolytic pathway and mitochondrial activity-Of leukemic cells and its role in the generation of resistance to conventional treatments, the modulation of the tumor microenvironment, and the evasion of immune response. In turn, it describes how the modulation of metabolism by plant-derived extracts can counteract resistance to chemotherapy in this tumor model and contribute to the activation of the antitumor immune system.

Exploring Prognostic Biomarkers of Acute Myeloid Leukemia to Determine Its Most Effective Drugs from the FDA-Approved List through Molecular Docking and Dynamic Simulation

Acute myeloid leukemia (AML) is a blood cancer caused by the abnormal proliferation and differentiation of hematopoietic stem cells in the bone marrow. The actual genetic markers and molecular mechanisms of AML prognosis are unclear till today. This study used bioinformatics approaches for identifying hub genes and pathways associated with AML development to uncover potential molecular mechanisms. The expression profiles of RNA-Seq datasets, GSE68925 and GSE183817, were retrieved from the Gene Expression Omnibus (GEO) database. These two datasets were analyzed by GREIN to obtain differentially expressed genes (DEGs), which were used for performing the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, protein-protein interaction (PPI), and survival analysis. The molecular docking and dynamic simulation were performed to identify the most effective drug/s for AML from the drug list approved by the Food and Drug Administration (FDA). By integrating the two datasets, 238 DEGs were identified as likely to be affected by AML progression. GO enrichment analyses exhibited that the upregulated genes were mainly associated with inflammatory response (BP) and extracellular region (CC). The downregulated DEGs were involved in the T-cell receptor signalling pathway (BP), an integral component of the lumenal side of the endoplasmic reticulum membrane (CC) and peptide antigen binding (MF). The pathway enrichment analysis showed that the upregulated DEGs were mainly associated with the T-cell receptor signalling pathway. Among the top 15 hub genes, the expression levels of ALDH1A1 and CFD were associated with the prognosis of AML. Four FDA-approved drugs were selected, and a top-ranked drug was identified for each biomarker through molecular docking studies. The top-ranked drugs were further confirmed by molecular dynamic simulation that revealed their binding stability and confirmed their stable performance. Therefore, the drug compounds, enasidenib and gilteritinib, can be recommended as the most effective drugs against the ALDH1A1 and CFD proteins, respectively.

Acute Myeloid Leukemia Causes Serious and Partially Irreversible Changes in Secretomes of Bone Marrow Multipotent Mesenchymal Stromal Cells

In patients with acute myeloid leukemia (AML), malignant cells modify the properties of multipotent mesenchymal stromal cells (MSCs), reducing their ability to maintain normal hematopoiesis. The aim of this work was to elucidate the role of MSCs in supporting leukemia cells and the restoration of normal hematopoiesis by analyzing ex vivo MSC secretomes at the onset of AML and in remission. The study included MSCs obtained from the bone marrow of 13 AML patients and 21 healthy donors. The analysis of proteins contained in the MSCs-conditioned medium demonstrated that secretomes of patient MSCs differed little between the onset of AML and remission; pronounced differences were observed between MSC secretomes of AML patients and healthy donors. The onset of AML was accompanied by a decrease in the secretion of proteins related to ossification, transport, and immune response. In remission, but not at the onset, secretion of proteins responsible for cell adhesion, immune response, and complement was reduced compared to donors. We conclude that AML causes crucial and, to a large extent, irreversible changes in the secretome of bone marrow MSCs ex vivo. In remission, functions of MSCs remain impaired despite the absence of tumor cells and the formation of benign hematopoietic cells.

The Class IIA Histone Deacetylase (HDAC) Inhibitor TMP269 Downregulates Ribosomal Proteins and Has Anti-Proliferative and Pro-Apoptotic Effects on AML Cells

Acute myeloid leukemia (AML) is a hematopoietic malignancy characterized by altered myeloid progenitor cell proliferation and differentiation. As in many other cancers, epigenetic transcriptional repressors such as histone deacetylases (HDACs) are dysregulated in AML. Here, we investigated (1) HDAC gene expression in AML patients and in different AML cell lines and (2) the effect of treating AML cells with the specific class IIA HDAC inhibitor TMP269, by applying proteomic and comparative bioinformatic analyses. We also analyzed cell proliferation, apoptosis, and the cell-killing capacities of TMP269 in combination with venetoclax compared to azacitidine plus venetoclax, by flow cytometry. Our results demonstrate significantly overexpressed class I and class II HDAC genes in AML patients, a phenotype which is conserved in AML cell lines. In AML MOLM-13 cells, TMP269 treatment downregulated a set of ribosomal proteins which are overexpressed in AML patients at the transcriptional level. TMP269 showed anti-proliferative effects and induced additive apoptotic effects in combination with venetoclax. We conclude that TMP269 exerts anti-leukemic activity when combined with venetoclax and has potential as a therapeutic drug in AML.

Circular RNAs and Untranslated Regions in Acute Myeloid Leukemia

Before the advent of next-generation sequencing, research on acute myeloid leukemia (AML) mostly centered on protein-coding genes. In recent years, breakthroughs in RNA sequencing technologies and whole transcriptome analysis have led to the discovery that approximately 97.5% of the human genome is transcribed into non-coding RNAs (ncRNAs). This paradigm shift has led to an explosion of research interest in different classes of non-coding RNAs, such as circular RNAs (circRNAs) as well as non-coding untranslated regions (UTRs) of protein-coding messenger RNAs. The critical roles of circRNAs and UTRs in AML pathogenesis have become increasingly apparent. In this review, we discuss the cellular mechanisms of circRNAs and summarize recent studies that reveal their biological roles in AML. Furthermore, we also review the contribution of 3'UTRs to disease progression. Finally, we discuss the potential of circRNAs and 3'UTRs as new biomarkers for disease stratification and/or the prediction of treatment response and targets for the development of RNA-directed therapeutic applications.

A DNA Damage Response Related Signature to Predict Prognosis in Patients with Acute Myeloid Leukemia

The prognosis of acute myeloid leukemia (AML) is disappointing in most subtypes and varies widely. DNA damage response (DDR) is associated with prognosis and immunotherapy in multiple cancers. Here, we identify a signature of eight DDR-related genes associated with overall survival, which stratifies AML patients into high- and low-risk groups. Patients in low-risk group were more likely to respond to sorafenib. The signature could be an independent prognostic predictor for patients treated with ADE and ADE plus gemtuzumab ozogamicin. Therefore, this DDR prognostic signature might be applied to prognostic stratification and treatment selection in AML patients, which warrants further studies.

Preclinical evaluation of the ROCK1 inhibitor, GSK269962A, in acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy with high mortality that urgently requires new treatments. ROCK1 plays an essential role in regulating growth and survival in AML cells. In this study, we evaluated GSK269962A, a selective ROCK1 inhibitor, in preclinical models of AML. Compared with solid tumors, GSK269962A selectively inhibited cell growth and clonogenicity of AML cells. Furthermore, GSK269962A arrested AML cells in the G2 phase and induced apoptosis by regulating multiple cell cycle- and apoptosis-associated proteins. Strikingly, GSK269962A could eliminate leukemia cells from bone marrow, liver, and spleen in an animal model of AML and significantly prolong mouse survival. Mechanistically, GSK269962A could inhibit the growth of AML by blocking ROCK1/c-Raf/ERK signaling pathway. Notably, a correlation was found between the expression levels of ROCK1 protein and the sensitivity of GSK269962A in AML. These data highlight the potential role of ROCK1 as an attractive target for treating AML, as well as the potential of GSK269962A for use in clinical trials of AML.

Modelling acute myeloid leukemia (AML): What's new? A transition from the classical to the modern

Acute myeloid leukemia (AML) is a heterogeneous malignancy affecting myeloid cells in the bone marrow (BM) but can spread giving rise to impaired hematopoiesis. AML incidence increases with age and is associated with poor prognostic outcomes. There has been a disconnect between the success of novel drug compounds observed in preclinical studies of hematological malignancy and less than exceptional therapeutic responses in clinical trials. This review aims to provide a state-of-the-art overview on the different preclinical models of AML available to expand insights into disease pathology and as preclinical screening tools. Deciphering the complex physiological and pathological processes and developing predictive preclinical models are key to understanding disease progression and fundamental in the development and testing of new effective drug treatments. Standard scaffold-free suspension models fail to recapitulate the complex environment where AML occurs. To this end, we review advances in scaffold/matrix-based 3D models and outline the most recent advances in on-chip technology. We also provide an overview of clinically relevant animal models and review the expanding use of patient-derived samples, which offer the prospect to create more "patient specific" screening tools either in the guise of 3D matrix models, microphysiological "organ-on-chip" tools or xenograft models and discuss representative examples.

Characteristics of Pyroptosis-Related Subtypes and Novel Scoring Tool for the Prognosis and Chemotherapy Response in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is usually associated with poor prognosis and low complete remission (CR) rate due to individual biological heterogeneity. Pyroptosis is a special form of inflammatory programmed cell death related to the progression, treatment response, and prognosis of multiple tumors. However, the potential connection of pyroptosis-related genes (PRGs) and AML still remains unclear. We described the genetic and transcriptional alterations of PRGs in 151 AML samples and presented a consensus clustering of these patients into two subtypes with distinct immunological and prognostic characteristics. Cluster A, associated with better prognosis, was characterized by relatively lower PRG expression, activated immune cells, higher immune scores in the tumor microenvironment (TME), and downregulation of immunotherapy checkpoints. Subsequently, a PRG score was constructed to predict overall survival (OS) of AML patients by using univariate and multivariate Cox regression analysis, and its immunological characteristics and predictive capability were further validated by 1,054 AML samples in external datasets. Besides an immune-activated status, low-PRG score cohorts exhibited higher chemotherapeutic drug sensitivity and significant positive correlation with the cancer stem cell (CSC) index. Combined with age, clinical French-American-British (FAB) subtypes, and PRG score, we successfully constructed a nomogram to effectively predict the 1-/3-/5-year survival rate of AML patients, and the predictive capability was further validated in multiple external datasets with a high area under the curve (AUC) value. The various transcriptomic analysis helps us screen significant pyroptosis-related signatures of AML and provide a new clinical application of PRG scores in predicting the prognosis and benefits of treatment for AML patients.

Leukotrienes promote stem cell self-renewal and chemoresistance in acute myeloid leukemia

Acute myeloid leukemia (AML) is characterized by poor clinical outcomes due to high rates of relapse following standard-of-care induction chemotherapy. While many pathogenic drivers have been described in AML, our understanding of the molecular mechanisms mediating chemotherapy resistance remains poor. Therefore, we sought to identify resistance genes to induction therapy in AML and elucidated ALOX5 as a novel mediator of resistance to anthracycline-based therapy. ALOX5 is transcriptionally upregulated in AML patient blasts in comparison to normal hematopoietic stem/progenitor cells (HSPCs) and ALOX5 mRNA, and protein expression is increased in response to induction therapy. In vitro, and in vivo genetic, and pharmacologic perturbation studies confirm that ALOX5 positively regulates the leukemogenic potential of AML LSCs, and its loss does not significantly affect the function of normal HSPCs. ALOX5 mediates resistance to daunorubicin (DNR) and promotes AML cell survival and maintenance through its leukotriene (LT) synthetic capacity, specifically via modulating the synthesis of LTB4 and its binding to LTB receptor (BLTR). Our study reveals a previously unrecognized role of LTs in AML pathogenesis and chemoresistance, whereby inhibition of ALOX5 mediated LTB4 synthesis and function could be combined with standard chemotherapy, to enhance the overall therapeutic efficacy in AML.

Artesunate improves venetoclax plus cytarabine AML cell targeting by regulating the Noxa/Bim/Mcl-1/p-Chk1 axis

Venetoclax plus cytarabine therapy is approved for elderly acute myeloid leukemia (AML) patients and needs further improvement. We studied the mechanisms of venetoclax plus cytarabine treatment and searched for a third agent to enhance their effects. Cytarabine induces S phase arrest-mediated DNA damage with activation of DNA replication checkpoint kinase 1 (Chk1) through phosphorylation, while venetoclax induces B cell lymphoma 2 (Bcl-2)-interacting mediator of cell death (Bim)-mediated apoptotic DNA damage. Myeloid cell leukemia-1 (Mcl-1) plays negative roles in both events by sequestering Bim and accelerating Chk1 phosphorylation. Venetoclax releases Bim from Bcl-2 with increased Bim binding to Mcl-1. Artesunate, an antimalaria drug, induces Noxa to replace Bim from Mcl-1 and induces synergistic apoptosis with venetoclax accompanied with Mcl-1 reduction. Silencing Mcl-1 or adding venetoclax/artesunate diminishes the cytarabine resistance pathway p-Chk1. The triple combination exhibits S phase arrest with enhanced DNA damage, improves AML colony formation inhibition, and prolongs survival of two mice xenograft models compared to the venetoclax/cytarabine dual combination. Artesunate serves as a bridge for venetoclax and cytarabine combination by Noxa and Bim-mediated apoptosis and Mcl-1 reduction. We provide a new triple combination for AML treatment by targeting the Noxa/Mcl-1/Bim axis to reverse Mcl-1/p-Chk1 resistance of cytarabine therapy.

Increasing Role of Targeted Immunotherapies in the Treatment of AML

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. The standard of care in medically and physically fit patients is intensive induction therapy. The majority of these intensively treated patients achieve a complete remission. However, a high number of these patients will experience relapse. In patients older than 60 years, the results are even worse. Therefore, new therapeutic approaches are desperately needed. One promising approach in high-risk leukemia to prevent relapse is the induction of the immune system simultaneously or after reduction of the initial tumor burden. Different immunotherapeutic approaches such as allogenic stem cell transplantation or donor lymphocyte infusions are already standard therapies, but other options for AML treatment are in the pipeline. Moreover, the therapeutic landscape in AML is rapidly changing, and in the last years, a number of immunogenic targets structures eligible for specific therapy, risk assessment or evaluation of disease course were determined. For example, leukemia-associated antigens (LAA) showed to be critical as biomarkers of disease state and survival, as well as markers of minimal residual disease (MRD). Yet many mechanisms and properties are still insufficiently understood, which also represents a great potential for this form of therapy. Therefore, targeted therapy as immunotherapy could turn into an efficient tool to clear residual disease, improve the outcome of AML patients and reduce the relapse risk. In this review, established but also emerging immunotherapeutic approaches for AML patients will be discussed.

Phytol and Heptacosane Are Possible Tools to Overcome Multidrug Resistance in an In Vitro Model of Acute Myeloid Leukemia

Drug resistance is the ability of cancer cells to gain resistance to both conventional and novel chemotherapy agents, and remains a major problem in cancer therapy. Resistance mechanisms are multifactorial and involve more strictly pharmacological factors, such as P-glycoprotein (P-gp) and biological factors such as inhibitor of apoptosis proteins (IAPs) and the nuclear factor-kappa B (NF-κB) pathway. Possible therapeutic strategies for the treatment of acute myeloid leukemia (AML) have increased in recent years; however, drug resistance remains a problem for most pa-tients. Phytol and heptacosane are the major compounds of Euphorbia intisy essential oil (EO) which were demonstrated to inhibit P-gp in a multidrug resistant in vitro model of AML. This study investigated the mechanism by which phytol and heptacosane improve P-gp-mediated drug transport. Phytol suppresses the P-gp expression via NF-κB inhibition and does not seem to act on the efflux system. Heptacosane acts as a substrate and potent P-gp inhibitor, demonstrating the ability to retain the substrate doxorubicin inside the cell and enhancing its cytotoxic effects. Our results suggest that these compounds act as non-toxic modulators of P-gp through different mechanisms and are able to revert P-gp-mediated drug resistance in tumor cells.

In vivo anti-tumor effect of PARP inhibition in IDH1/2 mutant MDS/AML resistant to targeted inhibitors of mutant IDH1/2

Treatment options for patients with relapsed/ refractory acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) are scarce. Recurring mutations, such as mutations in isocitrate dehydrogenase-1 and −2 (IDH1/2) are found in subsets of AML and MDS, are therapeutically targeted by mutant enzyme-specific small molecule inhibitors (IDH^mi). IDH mutations induce diverse metabolic and epigenetic changes that drive malignant transformation. IDH^mi alone are not curative and resistance commonly develops, underscoring the importance of alternate therapeutic options. We were first to report that IDH1/2 mutations induce a homologous recombination (HR) defect which confers sensitivity to poly (ADP)-ribose polymerase inhibitors (PARPi). Here, we show that the PARPi olaparib is effective against primary patient-derived IDH1/2-mutant AML/ MDS xeno-grafts (PDXs). Olaparib efficiently reduced overall engraftment and leukemia-initiating cell frequency as evident in serial transplantation assays in IDH1/2-mutant but not -wildtype AML/MDS PDXs. Importantly, we show that olaparib is effective in both IDH^mi-naïve and -resistant AML PDXs, critical given the high relapse and refractoriness rates to IDH^mi. Our pre-clinical studies provide a strong rationale for the translation of PARP inhibition to patients with IDH1/2-mutant AML/ MDS, providing an additional line of therapy for patients who do not respond to or relapse after targeted mutant IDH inhibition.

A Proteomic Platform Enables to Test for AML Normalization In Vitro

Acute promyelocytic leukaemia (APL) can be cured by the co-administration of arsenic trioxide (ATO) and all-trans retinoic acid (ATRA). These small molecules relieve the differentiation blockade of the transformed promyelocytes and trigger their maturation into functional neutrophils, which are physiologically primed for apoptosis. This normalization therapy represents a compelling alternative to cytotoxic anticancer chemotherapy, but lacks an in vitro model system for testing the efficiency of novel combination treatments consisting of inducers of differentiation and metallopharmaceuticals. Here, using proteome profiling we present an experimental framework that enables characterising the differentiation– and metal-specific effects of the combination treatment in a panel of acute myeloid leukaemia (AML) cell lines (HL-60 and U937), including APL (NB4). Differentiation had a substantial impact on the proteome on the order of 10% of the identified proteins and featured classical markers and transcription factors of myeloid differentiation. Additionally, ATO provoked specific cytoprotective effects in the AML cell lines HL-60 and U937. In HL-60, these effects included an integrated stress response (ISR) in conjunction with redox defence, while proteasomal responses and a metabolic rewiring were observed in U937 cells. In contrast, the APL cell line NB4 did not display such adaptions indicating a lack of plasticity to cope with the metal-induced stress, which may explain the clinical success of this combination treatment. Based on the induction of these cytoprotective effects, we proposed a novel metal-based compound to be used for the combination treatment instead of ATO. The organoruthenium drug candidate plecstatin-1 was previously shown to induce reactive oxygen species and an ISR. Indeed, the plecstatin-1 combination was found to affect similar pathways compared to the ATO combination in HL-60 cells and did not lead to cytoprotective response signatures in NB4. Moreover, the monocytic cell line U937 showed a low plasticity to cope with the plecstatin-1 combination, which suggests that this combination might achieve therapeutic benefit beyond APL. We propose that the cytoprotective plasticity of cancer cells might serve as a general proxy to discover novel combination treatments in vitro.

Lin28A/CENPE Promoting the Proliferation and Chemoresistance of Acute Myeloid Leukemia

The prognosis of chemoresistant acute myeloid leukemia (AML) is still poor, mainly owing to the sustained proliferation ability of leukemic cells, while the microtubules have a major role in sustaining the continuity of cell cycle. In the present study, we have identified CENPE, a microtubular kinesin-like motor protein that is highly expressed in the peripheral blood of patients with chemoresistant AML. In our in vitro studies, knockdown of CENPE expression resulted in the suppression of proliferation of myeloid leukemia cells and reversal of cytarabine (Ara-C) chemoresistance. Furthermore, Lin28A, one of the RNA-binding oncogene proteins that increase cell proliferation and invasion and contribute to unfavorable treatment responses in certain malignancies, was found to be remarkably correlated with CENPE expression in chemoresistance AML. Overexpression of LIN28A promoted the proliferation and Ara-C chemoresistance of leukemic cells. RIP assay, RNA pull-down, and dual luciferase reporter analyses indicated that LIN28A bound specifically to the promoter region GGAGA of CENPE. In addition, the impacts of LIN28A on cell growth, apoptosis, cell cycle progression, and Ara-C chemoresistance were reverted by the knockdown of CENPE. Hence, Lin28A/CENPE has enhanced the proliferation and chemoresistance of AML, and therefore, it could be a prospective candidate for AML treatment.

A multivalent Ara-C-prodrug nanoconjugate achieves selective ablation of leukemic cells in an acute myeloid leukemia mouse model

Current therapy in acute myeloid leukemia (AML) is based on chemotherapeutic drugs administered at high doses, lacking targeting selectivity and displaying poor therapeutic index because of severe adverse effects. Here, we develop a novel nanoconjugate that combines a self-assembled, multivalent protein nanoparticle, targeting the CXCR4 receptor, with an Oligo-Ara-C prodrug, a pentameric form of Ara-C, to highly increase the delivered payload to target cells. This 13.4 nm T22-GFP-H6-Ara-C nanoconjugate selectively eliminates CXCR4⁺ AML cells, which are protected by its anchoring to the bone marrow (BM) niche, being involved in AML progression and chemotherapy resistance. This nanoconjugate shows CXCR4-dependent internalization and antineoplastic activity in CXCR4⁺ AML cells in vitro. Moreover, repeated T22-GFP-H6-Ara-C administration selectively eliminates CXCR4⁺ leukemic cells in BM, spleen and liver. The leukemic dissemination blockage induced by T22-GFP-H6-Ara-C is significantly more potent than buffer or Oligo-Ara-C-treated mice, showing no associated on-target or off-target toxicity and, therefore, reaching a highly therapeutic window. In conclusion, T22-GFP-H6-Ara-C exploits its 11 ligands-multivalency to enhance target selectivity, while the Oligo-Ara-C prodrug multimeric form increases 5-fold its payload. This feature combination offers an alternative nanomedicine with higher activity and greater tolerability than current intensive or non-intensive chemotherapy for AML patients.

Medication-induced Pulmonary Injury: A Scenario- and Pattern-based Approach to a Perplexing Problem

Medication-induced pulmonary injury (MIPI) is a complex medical condition that has become increasingly common yet remains stubbornly difficult to diagnose. Diagnosis can be aided by combining knowledge of the most common imaging patterns caused by MIPI with awareness of which medications a patient may be exposed to in specific clinical settings. The authors describe six imaging patterns commonly associated with MIPI: sarcoidosis-like, diffuse ground-glass opacities, organizing pneumonia, centrilobular ground-glass nodules, linear-septal, and fibrotic. Subsequently, the occurrence of these patterns is discussed in the context of five different clinical scenarios and the medications and medication classes typically used in those scenarios. These scenarios and medication classes include the rheumatology or gastrointestinal clinic (disease-modifying antirheumatic agents), cardiology clinic (antiarrhythmics), hematology clinic (cytotoxic agents, tyrosine kinase inhibitors, retinoids), oncology clinic (immune modulators, tyrosine kinase inhibitors, monoclonal antibodies), and inpatient service (antibiotics, blood products). Additionally, the article draws comparisons between the appearance of MIPI and the alternative causes of lung disease typically seen in those clinical scenarios (eg, connective tissue disease-related interstitial lung disease in the rheumatology clinic and hydrostatic pulmonary edema in the cardiology clinic). Familiarity with the most common imaging patterns associated with frequently administered medications can help insert MIPI into the differential diagnosis of acquired lung disease in these scenarios. However, confident diagnosis is often thwarted by absence of specific diagnostic tests for MIPI. Instead, a working diagnosis typically relies on multidisciplinary consensus. ^©RSNA, 2021.

Therapeutic inhibition of GAS6-AS1/YBX1/MYC axis suppresses cell propagation and disease progression of acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is the most common type of leukemia in adults. Its therapy has not significantly improved during the past four decades despite intense research efforts. New molecularly targeted therapies are in great need. The proto-oncogene c-Myc (MYC) is an attractive target due to its transactivation role in multiple signaling cascades. Deregulation of the MYC is considered one of a series of oncogenic events required for tumorigenesis. However, limited knowledge is available on which mechanism underlie MYC dysregulation and how long non-coding RNAs (lncRNAs) are involved in MYC dysregulation in AML.

METHODS

AML microarray chips and public datasets were screened to identify novel lncRNA GAS6-AS1 was dysregulated in AML. Gain or loss of functional leukemia cell models were produced, and in vitro and in vivo experiments were applied to demonstrate its leukemogenic phenotypes. Interactive network analyses were performed to define intrinsic mechanism.

RESULTS

We identified GAS6-AS1 was overexpressed in AML, and its aberrant function lead to more aggressive leukemia phenotypes and poorer survival outcomes. We revealed that GAS6-AS1 directly binds Y-box binding protein 1 (YBX1) to facilitate its interaction with MYC, leading to MYC transactivation and upregulation of IL1R1, RAB27B and other MYC target genes associated with leukemia progression. Further, lentiviral-based GAS6-AS1 silencing inhibited leukemia progression in vivo.

CONCLUSIONS

Our findings revealed a previously unappreciated role of GAS6-AS1 as an oncogenic lncRNA in AML progression and prognostic prediction. Importantly, we demonstrated that therapeutic targeting of the GAS6-AS1/YBX1/MYC axis inhibits AML cellular propagation and disease progression. Our insight in lncRNA associated MYC-driven leukemogenesis may contribute to develop new anti-leukemia treatment strategies.

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

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

The correlation between Flt3-ITD mutation in dendritic cells with TIM-3 expression in acute myeloid leukemia

In general, acute myeloid leukemia (AML) is an aggressive and heterogeneous disease that is characterized by rapid cellular proliferation and high mortality. One of the mutations related to AML is the Flt3-ITD mutation, which is found in approximately 25% of patients. In this mini-review, we investigate the function of dendritic cells and T cells based on Flt3-ITD mutation and immune evasion as a result of this abnormality. Finally, we discuss some AML therapeutic strategies, including targeting Flt3 on DCs and TIM-3 on T cells as immune receptors to treat this hematopoietic malignancy.

Engineered type 1 regulatory T cells designed for clinical use kill primary pediatric acute myeloid leukemia cells

Type 1 regulatory (Tr1) T cells induced by enforced expression of interleukin-10 (LV-10) are being developed as a novel treatment for chemotherapy-resistant myeloid leukemias. In vivo, LV-10 cells do not cause graft-versus-host disease while mediating graft-versus-leukemia effect against adult acute myeloid leukemia (AML). Since pediatric AML (pAML) and adult AML are different on a genetic and epigenetic level, we investigate herein whether LV-10 cells also efficiently kill pAML cells. We show that the majority of primary pAML are killed by LV-10 cells, with different levels of sensitivity to killing. Transcriptionally, pAML sensitive to LV-10 killing expressed a myeloid maturation signature. Overlaying the signatures of sensitive and resistant pAML onto the public NCI TARGET pAML dataset revealed that sensitive pAML clustered with M5 monocytic pAML and pAML with MLL rearrangement. Resistant pAML clustered with myelomonocytic leukemias and those bearing the core binding factor translocations inv(16) or t(8;21)(RUNX1- RUNX1T1). Furthermore, resistant pAML upregulated the membrane glycoprotein CD200, which binds to the inhibitory receptor CD200R1 on LV-10 cells. In order to examine if CD200 expression on target cells can impair LV-10 cell function, we overexpressed CD200 in myeloid leukemia cell lines ordinarily sensitive to LV-10 killing. Indeed, LV-10 cells degranulated less and killed fewer CD200-overexpressing cells compared to controls, indicating that pAML can utilize CD200 expression for immune evasion. Altogether, the majority of pAML are killed by LV-10 cells in vitro, supporting further LV-10 cell development as an innovative cell therapy for pAML.

Adoptive immunotherapy with double-bright (CD56bright /CD16bright ) expanded natural killer cells in patients with relapsed or refractory acute myeloid leukaemia: a proof-of-concept study

Patients with acute myeloid leukaemia (AML) have a five-year survival rate of 28·7%. Natural killer (NK)-cell have anti-leukaemic activity. Here, we report on a series of 13 patients with high-risk R/R AML, treated with repeated infusions of double-bright (CD56^bright /CD16^bright ) expanded NK cells at an academic centre in Brazil. NK cells from HLA-haploidentical donors were expanded using K562 feeder cells, modified to express membrane-bound interleukin-21. Patients received FLAG, after which cryopreserved NK cells were thawed and infused thrice weekly for six infusions in three dose cohorts (10⁶ -10⁷ cells/kg/infusion). Primary objectives were safety and feasibility. Secondary endpoints included overall response (OR) and complete response (CR) rates at 28-30 days after the first infusion. Patients received a median of five prior lines of therapy, seven with intermediate or adverse cytogenetics, three with concurrent central nervous system (CNS) leukaemia, and one with concurrent CNS mycetoma. No dose-limiting toxicities, infusion-related fever, or cytokine release syndrome were observed. An OR of 78·6% and CR of 50·0% were observed, including responses in three patients with CNS disease and clearance of a CNS mycetoma. Multiple infusions of expanded, cryopreserved NK cells were safely administered after intensive chemotherapy in high-risk patients with R/R AML and demonstrated encouraging outcomes.

Insights into the molecular profiles of adult and paediatric acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a clinically and molecularly heterogeneous disease characterised by uncontrolled proliferation, block in differentiation and acquired self-renewal of hematopoietic stem and myeloid progenitor cells. This results in the clonal expansion of myeloid blasts within the bone marrow and peripheral blood. The incidence of AML increases with age, and in childhood, AML accounts for 20% of all leukaemias. Whilst there are many clinical and biological similarities between paediatric and adult AML with continuum across the age range, many characteristics of AML are associated with age of disease onset. These include chromosomal aberrations, gene mutations and differentiation lineage. Following chemotherapy, AML cells that survive and result in disease relapse exist in an altered chemoresistant state. Molecular profiling currently represents a powerful avenue of experimentation to study AML cells from adults and children pre- and postchemotherapy as a means of identifying prognostic biomarkers and targetable molecular vulnerabilities that may be age-specific. This review highlights recent advances in our knowledge of the molecular profiles with a focus on transcriptomes and metabolomes, leukaemia stem cells and chemoresistant cells in adult and paediatric AML and focus on areas that hold promise for future therapies.

Development and validation of a novel survival model for acute myeloid leukemia based on autophagy-related genes

Background

Acute myeloid leukemia (AML) is one of the most common blood cancers, and is characterized by impaired hematopoietic function and bone marrow (BM) failure. Under normal circumstances, autophagy may suppress tumorigenesis, however under the stressful conditions of late stage tumor growth autophagy actually protects tumor cells, so inhibiting autophagy in these cases also inhibits tumor growth and promotes tumor cell death.

Methods

AML gene expression profile data and corresponding clinical data were obtained from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, from which prognostic-related genes were screened to construct a risk score model through LASSO and univariate and multivariate Cox analyses. Then the model was verified in the TCGA cohort and GEO cohorts. In addition, we also analyzed the relationship between autophagy genes and immune infiltrating cells and therapeutic drugs.

Results

We built a model containing 10 autophagy-related genes to predict the survival of AML patients by dividing them into high- or low-risk subgroups. The high-risk subgroup was prone to a poorer prognosis in both the training TCGA-LAML cohort and the validation GSE37642 cohort. Univariate and multivariate Cox analysis revealed that the risk score of the autophagy model can be used as an independent prognostic factor. The high-risk subgroup had not only higher fractions of CD4 naïve T cell, NK cell activated, and resting mast cells but also higher expression of immune checkpoint genes CTLA4 and CD274. Last, we screened drug sensitivity between high- and low-risk subgroups.

Conclusion

The risk score model based on 10 autophagy-related genes can serve as an effective prognostic predictor for AML patients and may guide for patient stratification for immunotherapies and drugs.

Novel CAR T therapy is a ray of hope in the treatment of seriously ill AML patients

Acute myeloid leukemia (AML) is a serious, life-threatening, and hardly curable hematological malignancy that affects the myeloid cell progenies and challenges patients of all ages but mostly occurs in adults. Although several therapies are available including chemotherapy, allogeneic hematopoietic stem cell transplantation (alloHSCT), and receptor-antagonist drugs, the 5-year survival of patients is quietly disappointing, less than 30%. alloHSCT is the major curative approach for AML with promising results but the treatment has severe adverse effects such as graft-versus-host disease (GVHD). Therefore, as an alternative, more efficient and less harmful immunotherapy-based approaches such as the adoptive transferring T cell therapy are in development for the treatment of AML. As such, chimeric antigen receptor (CAR) T cells are engineered T cells which have been developed in recent years as a breakthrough in cancer therapy. Interestingly, CAR T cells are effective against both solid tumors and hematological cancers such as AML. Gradually, CAR T cell therapy found its way into cancer therapy and was widely used for the treatment of hematologic malignancies with successful results particularly with somewhat better results in hematological cancer in comparison to solid tumors. The AML is generally fatal, therapy-resistant, and sometimes refractory disease with a disappointing low survival rate and weak prognosis. The 5-year survival rate for AML is only about 30%. However, the survival rate seems to be age-dependent. Novel CAR T cell therapy is a light at the end of the tunnel. The CD19 is an important target antigen in AML and lymphoma and the CAR T cells are engineered to target the CD19. In addition, a lot of research goes on the discovery of novel target antigens with therapeutic efficacy and utilizable for generating CAR T cells against various types of cancers. In recent years, many pieces of research on screening and identification of novel AML antigen targets with the goal of generation of effective anti-cancer CAR T cells have led to new therapies with strong cytotoxicity against cancerous cells and impressive clinical outcomes. Also, more recently, an improved version of CAR T cells which were called modified or smartly reprogrammed CAR T cells has been designed with less unwelcome effects, less toxicity against normal cells, more safety, more specificity, longer persistence, and proliferation capability. The purpose of this review is to discuss and explain the most recent advances in CAR T cell-based therapies targeting AML antigens and review the results of preclinical and clinical trials. Moreover, we will criticize the clinical challenges, side effects, and the different strategies for CAR T cell therapy.

Evaluation of switch-mediated costimulation in trans on universal CAR-T cells (UniCAR) targeting CD123-positive AML

Chimeric antigen receptor T cells (CAR-T) targeting CD19 have achieved significant success in patients with B cell malignancies. To date, implementation of CAR-T in other indications remains challenging due to the lack of truly tumor-specific antigens as well as control of CAR-T activity in patients. CD123 is highly expressed in acute myeloid leukemia (AML) blasts including leukemia-initiating cells making it an attractive immunotherapeutic target. However, CD123 expression in normal hematopoietic progenitor cells and endothelia bears the risk of severe toxicities and may limit CAR-T applications lacking fine-tuned control mechanisms. Therefore, we recently developed a rapidly switchable universal CAR-T platform (UniCAR), in which CAR-T activity depends on the presence of a soluble adapter called targeting module (TM), and confirmed clinical proof-of-concept for targeting CD123 in AML with improved safety. As costimulation via 4–1BB ligand (4–1BBL) can enhance CAR-T expansion, persistence, and effector functions, a novel CD123-specific TM variant (TM123-4-1BBL) comprising trimeric single-chain 4–1BBL was developed for transient costimulation of UniCAR-T cells (UniCAR-T) at the leukemic site in trans. TM123-4-1BBL-directed UniCAR-T efficiently eradicated CD123-positive AML cells in vitro and in a CDX in vivo model. Moreover, additional costimulation via TM123-4-1BBL enabled enhanced expansion and persistence with a modulated UniCAR-T phenotype. In addition, the increased hydrodynamic volume of TM123-4-1BBL prolonged terminal plasma half-life and ensured a high total drug exposure in vivo. In conclusion, expanding the soluble adapter optionality for CD123-directed UniCAR-T maintains the platforms high anti-leukemic efficacy and immediate control mechanism for a flexible, safe, and individualized CAR-T therapy of AML patients.

Treatment of acute myeloid leukemia in children: A practical perspective

Pediatric acute myeloid leukemia (AML) is a heterogeneous disease that requires a multifaceted treatment approach. Although outcomes for low-risk AML have improved significantly over recent decades, high-risk AML continues to be associated with an adverse prognosis. Recent advances in molecular diagnostics, risk stratification, and supportive care have contributed to improvements in outcomes in pediatric AML. Targeted approaches, for example, the use of tyrosine kinase inhibitors to treat FLT3-ITD AML, offer promise and are currently undergoing clinical investigation in pediatric patients. New approaches to hematopoietic stem cell transplantation, including the use of haploidentical donors, are significantly expanding donor options for patients with high-risk AML. This review provides an overview of recent advances in the treatment of pediatric AML that are likely to have clinical impact and reshape the standard of care.

Profiling pharmacokinetics of double-negative T cells and cytokines via a single intravenous administration in NSG mice

This study was intended to delineate the profile of double-negative T cells (DNTs) in NOD.Cg-Prkdcscid Il2rgtm1wj /SzJ mice and cytokines released from DNTs in vivo and in vitro. Total 4 × 107 cells of RC1012 injection per mice were intravenously infused. IFN-γ, TNF-α, IL-1β, IL-2, IL-4, IL-6, IL-10 were measured in vivo and in vitro. A quantitative polymerase chain reaction (PCR) was employed to determine the gene copies of Notch2-NLA per DNT cell from collected organs. Cytokines were significantly increased in vitro (4 h) and in vivo (3 h). DNT cells were distributed into the lung, liver, heart, and kidney earlier, and redistributed to lymphocyte homing spleen and bone marrow, which seemed to frame a two-compartment pharmacokinetics (PK) model but more data are needed to confirm this, and the clearance of DNT cells fell into first-order kinetics.

Glutamate-cysteine ligase catalytic subunit as a therapeutic target in acute myeloid leukemia and solid tumors

Acute myeloid leukemia (AML) is a highly heterogenous and aggressive disease with a poor prognosis, necessitating further improvements in treatment therapies. Recently, several targeted therapies have become available for specific AML populations. To identify potential new therapeutic targets for AML, we analyzed published genome wide CRISPR-based screens to generate a gene essentiality dataset across a panel of 14 human AML cell lines while eliminating common essential genes through integration analysis with core fitness genes among 324 human cancer cell lines and DepMap databases. The key glutathione metabolic enzyme, glutamate-cysteine ligase catalytic subunit (GCLC), met the selection threshold. Using CRISPR knockout, GCLC was confirmed to be essential for the cell growth, survival, clonogenicity, and leukemogenesis in AML cells but was comparatively dispensable for normal hematopoietic stem and progenitor cells (HSPCs), indicating that GCLC is a potential therapeutic target for AML. In addition, we evaluated the essentiality of GCLC in solid tumors and demonstrated that GCLC represents a synthetic lethal target for ARID1A-deficient ovarian and gastric cancers.

Prognosis and Characterization of Immune Microenvironment in Acute Myeloid Leukemia Through Identification of an Autophagy-Related Signature

Acute myeloid leukemia (AML) is one of the most common hematopoietic malignancies that has an unfavorable outcome and a high rate of relapse. Autophagy plays a vital role in the development of and therapeutic responses to leukemia. This study identifies a potential autophagy-related signature to monitor the prognoses of patients of AML. Transcriptomic profiles of AML patients (GSE37642) with the relevant clinical information were downloaded from Gene Expression Omnibus (GEO) as the training set while TCGA-AML and GSE12417 were used as validation cohorts. Univariate regression analyses and multivariate stepwise Cox regression analysis were respectively applied to identify the autophagy-related signature. The univariate Cox regression analysis identified 32 autophagy-related genes (ARGs) that were significantly associated with the overall survival (OS) of the patients, and were mainly rich in signaling pathways for autophagy, p53, AMPK, and TNF. A prognostic signature that comprised eight ARGs (BAG3, CALCOCO2, CAMKK2, CANX, DAPK1, P4HB, TSC2, and ULK1) and had good predictive capacity was established by LASSO–Cox stepwise regression analysis. High-risk patients were found to have significantly shorter OS than patients in low-risk group. The signature can be used as an independent prognostic predictor after adjusting for clinicopathological parameters, and was validated on two external AML sets. Differentially expressed genes analyzed in two groups were involved in inflammatory and immune signaling pathways. An analysis of tumor-infiltrating immune cells confirmed that high-risk patients had a strong immunosuppressive microenvironment. Potential druggable OS-related ARGs were then investigated through protein–drug interactions. This study provides a systematic analysis of ARGs and develops an OS-related prognostic predictor for AML patients. Further work is needed to verify its clinical utility and identify the underlying molecular mechanisms in AML.

Delineation of Molecular Lesions in Acute Myeloid Leukemia Patients at Diagnosis: Integrated Next Generation Sequencing and Cytogenomic Studies

Acute myeloid leukemia (AML) is a heterogeneous disorder characterized by a wide range of genetic defects. Cytogenetics, molecular and genomic technologies have proved to be helpful for deciphering the mutational landscape of AML and impacted clinical practice. Forty-eight new AML patients were investigated with an integrated approach, including classical and molecular cytogenetics, array-based comparative genomic hybridization and targeted next generation sequencing (NGS). Various genetic defects were identified in all the patients using our strategy. Targeted NGS revealed known pathogenic mutations as well as rare or unreported variants with deleterious predictions. The mutational screening of the normal karyotype (NK) group identified clinically relevant variants in 86.2% of the patients; in the abnormal cytogenetics group, the mutation detection rate was 87.5%. Overall, the highest mutation prevalence was observed for the NPM1 gene, followed by DNMT3A, FLT3 and NRAS. An unexpected co-occurrence of KMT2A translocation and DNMT3A-R882 was identified; alterations of these genes, which are involved in epigenetic regulation, are considered to be mutually exclusive. A microarray analysis detected CNVs in 25% of the NK AML patients. In patients with complex karyotypes, the microarray analysis made a significant contribution toward the accurate characterization of chromosomal defects. In summary, our results show that the integration of multiple investigative strategies increases the detection yield of genetic defects with potential clinical relevance.

The polyphenol/saponin-rich Rhus tripartita extract has an apoptotic effect on THP-1 cells through the PI3K/AKT/mTOR signaling pathway

Background

Hyperactivation of mechanistic target of rapamycin (mTOR) signaling pathway is involved in the regulation of cellular growth, proliferation, and more in general, is a common phenomenon in most types of cancers. Thus, natural substances targeting this pathway can be of great therapeutic potential in supporting the treatment of tumor patients. Rhus tripartita (Ucria) Grande is a plant growing in desertic areas which is traditionally used for the treatment of several diseases in Tunisia. In the present work, the biochemical profile of the main compounds present in the plant leaf extract was determined and the anti-leukemic potential of the plant extracts against acute monocytic leukaemia (AML) THP-1 cells was investigated.

Methods

After HPLC identification of some phenolic compounds present in the plant extract and the quantification of saponin content, the cytotoxic effect of Rhus tripartita extracts on THP-1 cell culture was evaluated using the colorimetric MTT assay for cell viability. THP-1 cells were incubated with medium containing the relative IC₅₀ concentrations of total plant extract, saponin extract and some standard compounds (rutin (R); kaempferol (K); mixture of catechin, epicatechin, and epicatechin-gallate (CEEG); ellagic acid (EA). Finally, qRT-PCR and western blotting analysis were used to evaluate the effect of some flavonoids present in a crude extract of polyphenols and the total extract of saponins on cell survival and apoptosis.

Results

Analysis of expression level of some gene (PIK3CA, PTEN, AKT1, mTOR, EIF4E, RPS6KB1, and TSC1) involved in the mTOR pathway and the phosphorylation of S6 and AKT proteins allowed to observe that a total Rhus tripartita extract and some of the compounds found in the extract controls THP-1 cell proliferation and apoptosis via regulation of the PI3K-Akt-mTOR signaling pathway.

Conclusion

Rhus tripartita-induced inhibition of cell cycle and induction of apoptosis may involve the mTOR pathway. Therefore, Rhus tripartita extract may be a useful candidate as a natural anti-cancer drug to support the treatment of AML.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03328-9.

The Role of Metabolism in the Development of Personalized Therapies in Acute Myeloid Leukemia

Despite significant recent advances in our understanding of the biology and genetics of acute myeloid leukemia (AML), current AML therapies are mostly based on a backbone of standard chemotherapy which has remained mostly unchanged for over 20 years. Several novel therapies, mostly targeting neomorphic/activating recurrent mutations found in AML patients, have only recently been approved following encouraging results, thus providing the first evidence of a more precise and personalized approach to AML therapy. Rewired metabolism has been described as a hallmark of cancer and substantial evidence of its role in AML establishment and maintenance has been recently accrued in preclinical models. Interestingly, unique metabolic changes are generated by specific AML recurrent mutations or in response to diverse AML therapies, thus creating actionable metabolic vulnerabilities in specific patient groups. In this review we will discuss the current evidence supporting a role for rewired metabolism in AML pathogenesis and how these metabolic changes can be leveraged to develop novel personalized therapies.

Inhibitors of Chemoresistance Pathways in Combination with Ara-C to Overcome Multidrug Resistance in AML. A Mini Review

Acute myeloid leukemia (AML), the most common type of leukemia in older adults, is a heterogeneous disease that originates from the clonal expansion of undifferentiated hematopoietic progenitor cells. These cells present a remarkable variety of genes and proteins with altered expression and function. Despite significant advances in understanding the molecular panorama of AML and the development of therapies that target mutations, survival has not improved significantly, and the therapy standard is still based on highly toxic chemotherapy, which includes cytarabine (Ara-C) and allogeneic hematopoietic cell transplantation. Approximately 60% of AML patients respond favorably to these treatments and go into complete remission; however, most eventually relapse, develop refractory disease or chemoresistance, and do not survive for more than five years. Therefore, drug resistance that initially occurs in leukemic cells (primary resistance) or that develops during or after treatment (acquired resistance) has become the main obstacle to AML treatment. In this work, the main molecules responsible for generating chemoresistance to Ara-C in AML are discussed, as well as some of the newer strategies to overcome it, such as the inclusion of molecules that can induce synergistic cytotoxicity with Ara-C (MNKI-8e, emodin, metformin and niclosamide), subtoxic concentrations of chemotherapy (PD0332991), and potently antineoplastic treatments that do not damage nonmalignant cells (heteronemin or hydroxyurea + azidothymidine).

Therapeutic cancer vaccine therapy for acute myeloid leukemia

Antitumor function of the immune system has been harnessed to eradicate tumor cells as cancer therapy. Therapeutic cancer vaccines aim to help immune cells recognize tumor cells, which are difficult to target owing to immune escape. Many attempts at vaccine designs have been conducted throughout the last decades. In addition, as the advanced understanding of immunosuppressive mechanisms mediated by tumor cells, combining cancer vaccines with other immune therapies seems to be more efficient for cancer treatment. Acute myeloid leukemia (AML) is the most common acute leukemia in adults with poor prognosis. Evidence has shown T-cell-mediated immune responses in AML, which encourages the utility of immune therapies in AML. This review discusses cancer vaccines in AML from vaccine design as well as recent progress in vaccination combination with other immune therapies.

Peripheral blood molecular measurable residual disease is sufficient to identify patients with acute myeloid leukaemia with imminent clinical relapse

Longitudinal molecular measurable residual disease (MRD) sampling after completion of therapy serves as a refined tool for identification of imminent relapse of acute myeloid leukaemia (AML) among patients in long-term haematological complete remission. Tracking of increasing quantitative polymerase chain reaction MRD before cytomorphological reappearance of blasts may instigate individual management decisions and has paved the way for development of pre-emptive treatment strategies to substantially delay or perhaps even revert leukaemic regrowth. Traditionally, MRD monitoring is performed using repeated bone marrow aspirations, albeit the current European LeukemiaNet MRD recommendations acknowledge the use of peripheral blood as an alternative source for MRD assessment. Persistent MRD positivity in the bone marrow despite continuous morphological remission is frequent in both core binding factor leukaemias and nucleophosmin 1-mutated AML. In contrast, monthly assessment of MRD in peripheral blood superiorly separates patients with imminent haematological relapse from long-term remitters and may allow pre-emptive therapy of AML relapse.

Assessing acquired resistance to IDH1 inhibitor therapy by full-exon IDH1 sequencing and structural modeling

Somatic mutations in hotspot regions of the cytosolic or mitochondrial isoforms of the isocitrate dehydrogenase gene (IDH1 and IDH2, respectively) contribute to the pathogenesis of acute myeloid leukemia (AML) by producing the oncometabolite 2-hydroxyglutarate (2-HG). The allosteric IDH1 inhibitor, ivosidenib, suppresses 2-HG production and induces clinical responses in relapsed/refractory IDH1-mutant AML. Herein, we describe a clinical case of AML in which we detected the neomorphic IDH1 p.R132C mutation in consecutive patient samples with a mutational hotspot targeted next-generation sequencing (NGS) assay. The patient had a clinical response to ivosidenib, followed by relapse and disease progression. Subsequent sequencing of the relapsed sample using a newly developed all-exon, hybrid-capture-based NGS panel identified an additional IDH1 p.S280F mutation known to cause renewed 2-HG production and drug resistance. Structural modeling confirmed that serine-to-phenylalanine substitution at this codon sterically hinders ivosidenib from binding to the mutant IDH1 dimer interface and predicted a similar effect on the pan-IDH inhibitor AG-881. Joint full-exon NGS and structural modeling enables monitoring IDH1 inhibitor-treated AML patients for acquired drug resistance and choosing follow-up therapy.

Prognostic Significance of CD56 Antigen Expression in Patients with De Novo Non-M3 Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous group of disorders with distinct characteristics and prognoses. Although cytogenetic changes and gene mutations are associated with AML prognosis, there is a need to identify further factors. CD56 is considered a prognostic factor for AML, which is abnormally expressed in leukemia cells. However, a clear consensus for this surface molecule is lacking, which has prompted us to investigate its prognostic significance. Bone marrow samples of de novo non-M3 AML were collected to detect CD56 expression using multiparameter flow cytometry (FCM). As a result, the CD56 expression in de novo non-M3 AML was found to be significantly higher than that in acute lymphoma leukemia (ALL, P = 0.017) and healthy controls (P = 0.02). The X-Tile program produced a CD56 cutoff point at a relative expression level of 24.62%. Based on this cutoff point, high CD56 expression was observed in 29.21% of de novo non-M3 AML patients. CD56-high patients had a poor overall survival (OS, P = 0.015) compared to CD56-low patients. Bone marrow transplantation (BMT) improved OS (P = 0.004), but a poor genetic risk was associated with an inferior OS (P = 0.002). Compared with CD56-low patients, CD56-high patients had lower peripheral blood platelet (PLT) counts (P = 0.010). Our research confirmed that high CD56 expression is associated with adverse clinical outcomes in de novo non-M3 AML patients, indicating that CD56 could be used as a prognostic marker for a more precise stratification of de novo non-M3 AML patients.

Synergistic targeting of FLT3 mutations in AML via combined menin-MLL and FLT3 inhibition

The interaction of menin (MEN1) and MLL (MLL1, KMT2A) is a dependency and provides a potential opportunity for treatment of NPM1-mutant (NPM1mut) and MLL-rearranged (MLL-r) leukemias. Concomitant activating driver mutations in the gene encoding the tyrosine kinase FLT3 occur in both leukemias and are particularly common in the NPM1mut subtype. In this study, transcriptional profiling after pharmacological inhibition of the menin-MLL complex revealed specific changes in gene expression, with downregulation of the MEIS1 transcription factor and its transcriptional target gene FLT3 being the most pronounced. Combining menin-MLL inhibition with specific small-molecule kinase inhibitors of FLT3 phosphorylation resulted in a significantly superior reduction of phosphorylated FLT3 and transcriptional suppression of genes downstream of FLT3 signaling. The drug combination induced synergistic inhibition of proliferation, as well as enhanced apoptosis, compared with single-drug treatment in models of human and murine NPM1mut and MLL-r leukemias harboring an FLT3 mutation. Primary acute myeloid leukemia (AML) cells harvested from patients with NPM1mutFLT3mut AML showed significantly better responses to combined menin and FLT3 inhibition than to single-drug or vehicle control treatment, whereas AML cells with wild-type NPM1, MLL, and FLT3 were not affected by either of the 2 drugs. In vivo treatment of leukemic animals with MLL-r FLT3mut leukemia reduced leukemia burden significantly and prolonged survival compared with results in the single-drug and vehicle control groups. Our data suggest that combined menin-MLL and FLT3 inhibition represents a novel and promising therapeutic strategy for patients with NPM1mut or MLL-r leukemia and concurrent FLT3 mutation.