Leukemia Progression Research Articles

Clonal Evolution in 207 Cases of Refractory or Relapsed Acute Myeloid Leukemia.

Clonal evolution (CE) is a driving force behind the development and progression of acute myeloid leukemia (AML). Advances in molecular and cytogenetic assays have improved the depth and breadth of detection of CE in AML, which is defined here as a detected change in cytogenetic or molecular profile at relapsed or refractory (RR) disease. In this study, we demonstrate the clinical impact of CE in a cohort of patients with RR AML treated between 2013 and 2023. We discovered CE is significantly more frequent in relapsed disease (58.2%, [46.6%, 69.2%]) than in refractory disease (21.1%, [14.4%, 29.2%], p < 0.001). CE negatively impacts prognosis when detected by conventional karyotyping in refractory disease (4.2 vs. 13.9 months, p < 0.011). In contrast with prior literature, CE had no impact on overall survival if detected in relapsed disease. Surprisingly, those who achieved negative measurable residual disease (MRD) were no more likely to eliminate their original clone than those who did not (p = 1). We found several cytogenetic and molecular signatures which may predispose to CE: aberrations of chromosome 17, trisomy 8, TP53, KRAS, and FLT3-TKD. Finally, physicians were less likely to retreat those with CE with IC after receiving IC as first-line therapy (35.0% vs. 70.9%, p = 0.004). This study illustrates the role of CE in chemotherapy-resistant AML; we identify unique cytogenetic and molecular signatures that define a subset of patients associated with a dismal prognosis. As next-generation sequencing panels expand and new methods to characterize cytogenetic abnormalities emerge, our findings establish a basis for future studies investigating the prognostic and therapeutic impact of CE.

Hsa_circ_0006010 and hsa_circ_0002903 in peripheral blood serve as novel diagnostic, surveillance and prognostic biomarkers for disease progression in chronic myeloid leukemia

BackgroundIn the era of tyrosine kinase inhibitor (TKI) treatment, the progression of chronic myeloid leukemia (CML) remains a significant clinical challenge, and genetic biomarkers for the early identification of CML patients at risk for progression are limited. This study explored whether essential circular RNAs (circRNAs) can be used as biomarkers for diagnosing and monitoring CML disease progression and assessing CML prognosis.MethodsPeripheral blood (PB) samples were collected from 173 CML patients (138 patients with chronic phase CML [CML-CP] and 35 patients with accelerated phase/blast phase CML [CML-AP/BP]) and 63 healthy controls (HCs). High-throughput RNA sequencing (RNA-Seq) was used to screen dysregulated candidate circRNAs for a circRNA signature associated with CML disease progression. Quantitative real-time PCR (qRT-PCR) was used for preliminary verification and screening of candidate dysregulated genes, as well as subsequent exploration of clinical applications. Receiver operating characteristic (ROC) curve analysis, Spearman’s rho correlation test, and the Kaplan-Meier method were used for statistical analysis.ResultsThe aberrant expression of hsa_circ_0006010 and hsa_circ_0002903 during CML progression could serve as valuable biomarkers for differentiating CML-AP/BP patients from CMP-CP patients or HCs. In addition, the expression levels of hsa_circ_0006010 and hsa_circ_0002903 were significantly associated with the clinical features of CML patients but were not directly related to the four scoring systems. Furthermore, survival analysis revealed that high hsa_circ_0006010 expression and low hsa_circ_0002903 expression indicated poor progression-free survival (PFS) in CML patients. Finally, PB hsa_circ_0006010 and hsa_circ_0002903 expression at diagnosis may also serve as disease progression surveillance markers for CML patients but were not correlated with PB BCR-ABL1/ABL1IS.ConclusionsOur study demonstrated that PB levels of hsa_circ_0006010 and hsa_circ_0002903 may serve as novel diagnostic, surveillance, and prognostic biomarkers for CML disease progression and may contribute to assisting in the diagnosis of CML patients at risk for progression and accurate management of advanced CML patients.

Developmental interplay between transcriptional alterations and a targetable cytokine signaling dependency in pediatric ETO2::GLIS2 leukemia

BackgroundSeveral fusion oncogenes showing a higher incidence in pediatric acute myeloid leukemia (AML) are associated with heterogeneous megakaryoblastic and other myeloid features. Here we addressed how developmental mechanisms influence human leukemogenesis by ETO2::GLIS2, associated with dismal prognosis.MethodsWe created novel ETO2::GLIS2 models of leukemogenesis through lentiviral transduction and CRISPR-Cas9 gene editing of human fetal and post-natal hematopoietic stem/progenitor cells (HSPCs), performed in-depth characterization of ETO2::GLIS2 transformed cells through multiple omics and compared them to patient samples. This led to a preclinical assay using patient-derived-xenograft models to test a combination of two clinically-relevant molecules.ResultsWe showed that ETO2::GLIS2 expression in primary human fetal CD34+ hematopoietic cells led to more efficient in vivo leukemia development than expression in post-natal cells. Moreover, cord blood-derived leukemogenesis has a major dependency on the presence of human cytokines, including IL3 and SCF. Single cell transcriptomes revealed that this cytokine environment controlled two ETO2::GLIS2-transformed states that were also observed in primary patient cells. Importantly, this cytokine sensitivity may be therapeutically-exploited as combined MEK and BCL2 inhibition showed higher efficiency than individual molecules to reduce leukemia progression in vivo.ConclusionsOur study uncovers an interplay between the cytokine milieu and transcriptional programs that extends a developmental window of permissiveness to transformation by the ETO2::GLIS2 AML fusion oncogene, controls the intratumoral cellular heterogeneity, and offers a ground-breaking therapeutical opportunity by a targeted combination strategy.

USP4 regulates ribosome biogenesis and protein synthesis for hematopoietic stem cell regeneration and leukemia progression.

Enhanced ribosome biogenesis and protein synthesis are required for cell proliferation. During hematopoietic regeneration, hematopoietic stem cells (HSCs) proliferate rapidly to replenish the hematopoietic system. How HSCs respond and regulate ribosome biogenesis and protein synthesis during regeneration remains unclear. Here, we analyzed the expression of a series of ubiquitin-specific-proteases (USPs) during HSC regeneration. We found USP4 expression is significantly increased in proliferating HSCs. Further functional and mechanistic investigations revealed a crucial regulatory function of USP4 in HSC regeneration and leukemia progression by modulating ribosome biogenesis and protein synthesis. USP4 deubiquitinates and stabilizes PES1 to facilitate ribosome biogenesis and protein synthesis in proliferative HSCs and leukemic cells. Usp4 deletion significantly decreases protein synthesis, proliferation and reconstitution capacity of HSCs. Usp4 inhibition suppresses ribosome biogenesis and proliferation of leukemic cells, and prolongs the survival of AML (Acute myeloid leukemia) mice. These findings provide a new insight into the response mechanism of ribosome biogenesis and protein synthesis in HSCs, and their contribution to leukemia progression.

C-Myc alone is enough to reprogram fibroblasts into functional macrophages

BackgroundMacrophage-based cell therapy is promising in solid tumors, but the efficient acquisition of macrophages remains a challenge. Induced pluripotent stem cell (iPSC)-induced macrophages are a valuable source, but time-consuming and costly. The application of reprogramming technologies allows for the generation of macrophages from somatic cells, thereby facilitating the advancement of cell-based therapies for numerous malignant diseases.MethodsThe composition of CD45+ myeloid-like cell complex (MCC) and induced macrophage (iMac) were analyzed by flow cytometry and single-cell RNA sequencing. The engraftment capacity of CD45+ MCC was evaluated by two transplantation assays. Regulation of c-Myc on MafB was evaluated by ChIP-qPCR and promoter reporter and dual luciferase assays. The phenotype and phagocytosis of iMac were explored by flow cytometry and immunofluorescence. Leukemia, breast cancer, and patient-derived tumor xenograft models were used to explore the anti-tumor function of iMac.ResultsHere we report on the establishment of a novel methodology allowing for reprogramming fibroblasts into functional macrophages with phagocytic activity by c-Myc overexpression. Fibroblasts with ectopic expression of c-Myc in iPSC medium rapidly generated CD45+ MCC intermediates with engraftment capacity as well as the repopulation of distinct hematopoietic compartments. MCC intermediates were stably maintained in iPSC medium and continuously generated functional and highly pure iMac just by M-CSF cytokine stimulation. Single-cell transcriptomic analysis of MCC intermediates revealed that c-Myc up-regulated the expression of MafB, a major regulator of macrophage differentiation, to promote macrophage differentiation. Characterization of the iMac activity showed NF-κB signaling activation and a pro-inflammatory phenotype. iMac cells displayed significantly increased in vivo persistence and inhibition of tumor progression in leukemia, breast cancer, and patient-derived tumor xenograft models.ConclusionsOur findings demonstrate that c-Myc alone is enough to reprogram fibroblasts into functional macrophages, supporting that c-Myc reprogramming strategy of fibroblasts can help circumvent long-standing obstacles to gaining “off-the-shelf” macrophages for anti-cancer immunotherapy.

HDAC2-miR183-5p Epigenetic Circuit Contributes to the Growth of Philadelphia Chromosome-Positive B-cell Acute Lymphoblastic Leukemia via PTEN/AKT and c-MYC Signaling Pathway.

Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia (Ph(+)B-ALL) is a hematological malignancy with a poor prognosis. Epigenetic abnormalities, especially abnormal histone acetylation and microRNAs (miRNAs) dysregulation, are a group of epigenetic patterns that contribute to leukemia progression. However, their regulatory mechanisms in Ph(+)B-ALL have not been fully elucidated. In this study, we identified that miR-183-5p is significantly downregulated in Ph(+)B-ALL and associated with poor prognosis. Moreover, we found that the BCR-ABL fusion gene is a key target gene of miR-183-5p. MiR-183-5p directly targets BCR-ABL gene and induces cell apoptosis via PTEN/AKT and c-MYC signaling pathways. In addition, histone deacetylase inhibitor (HADCi) could mitigate the suppressive effects of HDAC2 on miR-183-5p by promoting promoter acetylation, thereby enhancing cell apoptosis. In conclusion, our results indicate that miR-183-5p is a potential biomarker and suggest that a novel "HDAC2-miR-183-5p epigenetic circuitry regulation" may be involved in the pathogenesis of Ph(+)B-ALL. Taken together, These findings provide new insights into the design of promising molecular-targeted drugs for Ph(+)B-ALL.

Cannabinoid combination targets NOTCH1-mutated T-cell acute lymphoblastic leukemia through the integrated stress response pathway.

In T-cell acute lymphoblastic leukemia (T-ALL), more than 50% of cases display autoactivation of Notch1 signaling, leading to oncogenic transformation. We have previously identified a specific chemovar of Cannabis that induces apoptosis by preventing Notch1 maturation in leukemia cells. Here, we isolated three cannabinoids from this chemovar that synergistically mimic the effects of the whole extract. Two were previously known, cannabidiol (CBD) and cannabidivarin (CBDV), whereas the third cannabinoid, which we termed 331-18A, was identified and fully characterized in this study. We demonstrated that these cannabinoids act through cannabinoid receptor type 2 and TRPV1 to activate the integrated stress response pathway by depleting intracellular Ca2+. This is followed by increased mRNA and protein expression of ATF4, CHOP, and CHAC1, which is hindered by inhibiting the upstream initiation factor eIF2α. The increased abundance of CHAC1 prevents Notch1 maturation, thereby reducing the levels of the active Notch1 intracellular domain, and consequently decreasing cell viability and increasing apoptosis. Treatment with the three isolated molecules resulted in reduced tumor size and weight in vivo and slowed leukemia progression in mice models. Altogether, this study elucidated the mechanism of action of three distinct cannabinoids in modulating the Notch1 pathway, and constitutes an important step in the establishment of a new therapy for treating NOTCH1-mutated diseases and cancers such as T-ALL.

Multi-Walled Carbon Nanotubes Accelerate Leukaemia Development in a Mouse Model.

Inflammation is associated with an increased risk of developing various cancers in both animals and humans, primarily solid tumors but also myeloproliferative neoplasms (MPNs), myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). Multi-walled carbon nanotubes (MWCNTs), a type of carbon nanotubes (CNTs) increasingly used in medical research and other fields, are leading to a rising human exposure. Our study demonstrated that exposing mice to MWCNTs accelerated the progression of spontaneous MOL4070LTR virus-induced leukemia. Additionally, similar exposures elevated pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α and induced reactive oxygen species (ROS) in a murine macrophage cell line. These effects were significantly reduced in immunodeficient mice and when mice were treated with methoxypolyethylene glycol amine (PEG)-modified MWCNTs. These findings underscore the necessity of evaluating the safety of MWCNTs, particularly for those with hematologic cancers.

Immune-dysregulation harnessing in myeloid neoplasms.

Myeloid malignancies arise in bone marrow microenvironments and shape these microenvironments in favor of malignant development. Immune suppression is one of the most important stages in myeloid leukemia progression. Leukemic clone expansion and immune dysregulation occur simultaneously in bone marrow microenvironments. Complex interactions emerge between normal immune system elements and leukemic clones in the bone marrow. In recent years, researchers have identified several of these pathological interactions. For instance, recent works shows that the secretion of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), from bone marrow stromal cells contributes to immune dysregulation and the selective proliferation of JAK2V617F+ clones in myeloproliferative neoplasms. Moreover, inflammasome activation and sterile inflammation result in inflamed microenvironments and the development of myelodysplastic syndromes. Additional immune dysregulations, such as exhaustion of T and NK cells, an increase in regulatory T cells, and impairments in antigen presentation are common findings in myeloid malignancies. In this review, we discuss the role of altered bone marrow microenvironments in the induction of immune dysregulations that accompany myeloid malignancies. We also consider both current and novel therapeutic strategies to restore normal immune system function in the context of myeloid malignancies.

A potent and selective ENL degrader suppresses oncogenic gene expression and leukemia progression.

The histone acylation reader eleven-nineteen leukemia (ENL) plays a pivotal role in sustaining oncogenesis in acute leukemias, particularly in mixed-lineage leukemia-rearranged (MLL-r) leukemia. ENL relies on its reader domain to recognize histone lysine acylation promoting oncogenic gene expression and leukemia progression. Here, we report the development of MS41, a highly potent and selective von Hippel-Lindau-recruiting ENL degrader that effectively inhibits the growth of ENL-dependent leukemia cells. MS41-induced ENL degradation reduces the chromatin occupancy of ENL-associated transcription elongation machinery, resulting in the suppression of key oncogenic gene expression programs and the activation of differentiation genes. MS41 is well-tolerated in vivo and substantially suppresses leukemia progression in a xenograft mouse model of MLL-r leukemia. Notably, MS41 also induces the degradation of mutant ENL proteins identified in Wilms' tumors. Our findings emphasize the therapeutic potential of pharmacological ENL degradation for treating ENL-dependent cancers, making MS41 not only a valuable chemical probe but also potential anticancer therapeutic for further development.

Identification of immunity- and ferroptosis-related signature genes as potential design targets for mRNA vaccines in AML patients.

Immune-associated ferroptosis plays an important role in the progression of acute myeloid leukemia (AML); however, the targets that play key roles in this process are currently unknown. This limits the development of mRNA vaccines based on immune-associated ferroptosis for clinical therapeutic applications. In this study, based on the rich data resources of the TCGA-LAML cohort, we analyzed the tumor mutational burden (TMB), gene mutation status, and associations between immune and ferroptosis genes to reveal the disease characteristics of AML patients. To gain a deeper understanding of differentially expressed genes, we applied the Limma package for differential expression analysis and integrated data sources such as ImmPort Shared Data and FerrDb V2. Moreover, we established gene modules related to TMB according to weighted gene coexpression network analysis (WGCNA) and explored the functions of these modules in AML and their relationships with TMB. We focused on the top 30 most frequent genes through a detailed survey of missense mutations and single nucleotide polymorphisms (SNPs) and selected potentially critical gene targets for subsequent analysis. Based on the expression of these genes, we successfully subgrouped AML patients and found that the subgroups associated with TMB (C1 and C2) exhibited significant differences in survival. The differences in the tumor microenvironment and immune cells between C1 and C2 patients were investigated with the ESTIMATE and MCP-counter algorithms. A predictive model of TMB-related genes (TMBRGs) was constructed, and the validity of the model was demonstrated by categorizing patients into high-risk and low-risk groups. The differences in survival between the high-risk patients and high-TMB patients were further investigated, and potential vaccine targets were identified via immune cell-level analysis. The identification of immunity- and ferroptosis-associated signature genes is an independent predictor of survival in AML patients and provides new information on immunotherapy for AML.

Incorporation mutational profile might reduce the importance of blast count in prognostication of low-risk myelodysplastic syndromes.

Addition of molecular data to prognostic models has improved risk stratification of myelodysplastic neoplasms (MDS). However, the role of molecular lesions, particularly in the group of low-risk disease (LR-MDS), is uncertain. We evaluated a set of 227 patients with LR-MDS. Overall survival (OS) and probability of leukaemic progression were the main endpoints. RUNX1 was associated with lower OS and SF3B1 with a reduced risk of death (HR: 1.7, 95% CI, 1.1-2.9; p = 0.05; and HR: 0.23, 95% CI 0.1-0.5; p < 0.001; respectively). TP53 and RUNX1 mutations were predictive covariates for the probability of leukaemic progression (p < 0.001). Blast percentage, neither analysed as categorical (<5% vs. 5%-9%; HR: 1.3, 95% CI, 0.7-2.9; p = 0.2) nor as a continuous variable (HR: 1.07, 95% CI, 0.9-1.1; p = 0.07), had impact on survival or probability of progression (sHR: 1.05, 95% CI, 0.9-1.1; p = 0.2). These results retained statistical significance when analysis was restricted to the definition of LR-MDS according to the WHO 2022 and ICC classifications (<5% blasts). Thus, with the incorporation of molecular data, blast percentage happens to lose clinical significance both for survival and probability of progression in the group of patients with LR-MDS.

Establishment and verification of a TME prognosis scoring model based on the acute myeloid leukemia single-cell transcriptome

The tumor microenvironment (TME) plays an important role in the occurrence and progression of Acute Myeloid Leukemia (AML). Single-cell sequencing has enabled researchers to explore the correlation between TME subgroups and tumor prognosis, distinguish the existence of drug-resistant subgroups of tumor cells, and unravel the complexity of the AML cellular heterogeneity. We used bone marrow immune cell enrichment analysis from public databases to screen prognostic genes, construct prognostic models, and validate their prognostic significance on independent external datasets and patient samples. A total of 18,251 single cells were obtained to establish prognostic scoring models for 10 key genes including CCL5, ETLS2, and IL2RA.The AML cases were divided into two groups: high-risk and low-risk. The low-risk group exhibited a higher survival rate than the high-risk group. The areas under curves (AUC) of 1-, 3- and 5-year survival curves in the TCGA and GEO training sets were greater than 0.8 and 0.6, respectively, indicating effective prediction. The model’s prognostic efficacy was confirmed across multiple validation sets. It demonstrated increased expression of ETS2, CCL5, and IL2RA in AML samples compared to controls, which was associated with decreased overall survival (OS). This prognostic scoring model based on tumor immune infiltration provides a reference for developing novel treatment strategies for recurrent/refractory AML.

BRG1 promotes progression of B-cell acute lymphoblastic leukemia by disrupting PPP2R1A transcription

Despite advancements in chemotherapy and the availability of novel therapies, the outcome of adult patients with B-cell acute lymphoblastic leukemia (B-ALL) remains unsatisfactory. Therefore, it is necessary to understand the molecular mechanisms underlying the progression of B-ALL. Brahma-related gene 1 (BRG1) is a poor prognostic factor for multiple cancers. Here, the expression of BRG1 was found to be higher in patients with B-ALL, irrespective of the molecular subtype, than in healthy individuals, and its overexpression was associated with a poor prognosis. Upregulation of BRG1 accelerated cell cycle progression into the S phase, resulting in increased cell proliferation, whereas its downregulation facilitated the apoptosis of B-ALL cells. Mechanistically, BRG1 occupies the transcriptional activation site of PPP2R1A, thereby inhibiting its expression and activating the PI3K/AKT signaling pathway to regulate the proto-oncogenes c-Myc and BCL-2. Consistently, silencing of BRG1 and administration of PFI-3 (a specific inhibitor targeting BRG1) significantly inhibited the progression of leukemia and effectively prolonged survival in cell-derived xenograft mouse models of B-ALL. Altogether, this study demonstrates that BRG1-induced overactivation of the PPP2R1A/PI3K/AKT signaling pathway plays an important role in promoting the progression of B-ALL. Therefore, targeting BRG1 represents a promising strategy for the treatment of B-ALL in adults.

CML-266 SETD2 Loss Contributes to Chronic Myeloid Leukemia Progression Affecting DNA Integrity and Epigenetic Landscape

CML-266 SETD2 Loss Contributes to Chronic Myeloid Leukemia Progression Affecting DNA Integrity and Epigenetic Landscape

SETD2 Loss Contributes to Chronic Myeloid Leukemia Progression Affecting DNA Integrity and Epigenetic Landscape

SETD2 Loss Contributes to Chronic Myeloid Leukemia Progression Affecting DNA Integrity and Epigenetic Landscape

Intermediate-based virtual screening of c-Kit kinase inhibitors as potential anti-tumor agents via ab inito folding, molecular dynamics simulation, and molecular docking

Uncontrolled activation of c-Kit is closely related to the pathogenesis and progression of leukemia, gastrointestinal cancer, and other malignant diseases. Although there are several inhibitors available, due to the limitation of selectivity and the unfavorable side effects, designing and discovering highly selective inhibitors targeting c-Kit kinase, especially the gain of function mutation (for example c-Kit D816V), is still necessary. To identify novel c-Kit inhibitors, a metastable state-based virtual screening approach, which was successfully implemented in other kinase inhibitors, was employed in the current study. The results from our current study demonstrated the residues adjacent to the DFG motif within the activation loop could fold into short α-helices aside from the random coil, which was commonly found in the crystal structure. By expanding the conformation pool of the activation loop via PyRosetta-based ab initio folding protocol, we constructed a series of structural models of the c-Kit kinase intermediate between the inactive and active states. After evaluation of the thermal stability of the metastable state with molecular dynamics simulation, one structural model showed higher stability of α-helix, and the activation loop was retained. Considering the wild-type and D816V mutated KIT kinase shared similar metastable states during the kinase activation process, we developed a hypothesis that the identified intermediate might hold the potential to identify inhibitors targeting D816V mutations from the compound database. As expected, the intermediate structure showed higher selectivity to KIT D816V selective inhibitors, such as bezuclastinib, avapritinib, BLU-263, and elenestinib, than imatinib or masitinib. The virtual screening of the available KIT kinase inhibitor database further identified vorolanib, semaxanib, henatinib, and pexmetinib may possess potential inhibitory effects against wild type, as well as the mutated c-Kit kinase. The results from our current study not only proposed a novel structural model that could be used for the identification of selective c-Kit D816V inhibitors but also identified several potential inhibitors from available kinase inhibitors, which might shed new light on the design of new therapeutic approaches for c-Kit mutation-driven malignant diseases.

Metabolic Function and Therapeutic Potential of CD147 for Hematological Malignancies: An Overview.

Hematological malignancies refer to a heterogeneous group of neoplastic conditions of lymphoid and hematopoietic tissues classified in leukemias, Hodgkin and non-Hodgkin lymphomas and multiple myeloma, according to their presumed cell of origin, genetic abnormalities, and clinical features. Metabolic adaptation and immune escape, which influence various cellular functions, including the proliferation and survival of hematological malignant tumor cells, are major aspects of these malignancies that lead to therapeutic drug resistance. Targeting specific metabolic pathways is emerging as a novel therapeutic strategy in hematopoietic neoplasms, particularly in acute myeloid leukemia and multiple myeloma. In this context, CD147, also known as extracellular matrix metalloproteinase inducer (EMMPRIN) or Basigin, is one target candidate involved in reprograming metabolism in different cancer cells, including hematological malignant tumor cells. CD147 overexpression significantly contributes to the metabolic transformation of these cancer cells, by mediating signaling pathway, growth, metastasis and metabolic reprogramming, through its interaction, direct or not, with various membrane proteins related to metabolic regulation, including monocarboxylate transporters, integrins, P-glycoprotein, and glucose transporter 1. This review explores the metabolic functions of CD147 and its impact on the tumor microenvironment, influencing the progression and neoplastic transformation of leukemias, myeloma, and lymphomas. Furthermore, we highlight new opportunities for the development of targeted therapies against CD147, potentially improving the treatment of hematologic malignancies.

Identification of leukemia stem cell subsets with distinct transcriptional, epigenetic and functional properties

The leukemia stem cell (LSC) compartment is a complex reservoir fueling disease progression in acute myeloid leukemia (AML). The existence of heterogeneity within this compartment is well documented but prior studies have focused on genetic heterogeneity without being able to address functional heterogeneity. Understanding this heterogeneity is critical for the informed design of therapies targeting LSC, but has been hampered by LSC scarcity and the lack of reliable cell surface markers for viable LSC isolation. To overcome these challenges, we turned to the patient-derived OCI-AML22 cell model. This model includes functionally, transcriptionally and epigenetically characterized LSC broadly representative of LSC found in primary AML samples. Focusing on the pool of LSC, we used an integrated approach combining xenograft assays with single-cell analysis to identify two LSC subtypes with distinct transcriptional, epigenetic and functional properties. These LSC subtypes differed in depth of quiescence, differentiation potential, repopulation capacity, sensitivity to chemotherapy and could be isolated based on CD112 expression. A majority of AML patient samples had transcriptional signatures reflective of either LSC subtype, and some even showed coexistence within an individual sample. This work provides a framework for investigating the LSC compartment and designing combinatorial therapeutic strategies in AML.

The Role of Epithelial-to-Mesenchymal Transition Transcription Factors (EMT-TFs) in Acute Myeloid Leukemia Progression.

Acute myeloid leukemia (AML) is a diverse malignancy originating from myeloid progenitor cells, with significant genetic and clinical variability. Modern classification systems like those from the World Health Organization (WHO) and European LeukemiaNet use immunophenotyping, molecular genetics, and clinical features to categorize AML subtypes. This classification highlights crucial genetic markers such as FLT3, NPM1 mutations, and MLL-AF9 fusion, which are essential for prognosis and directing targeted therapies. The MLL-AF9 fusion protein is often linked with therapy-resistant AML, highlighting the risk of relapse due to standard chemotherapeutic regimes. In this sense, factors like the ZEB, SNAI, and TWIST gene families, known for their roles in epithelial-mesenchymal transition (EMT) and cancer metastasis, also regulate hematopoiesis and may serve as effective therapeutic targets in AML. These genes contribute to cell proliferation, differentiation, and extramedullary hematopoiesis, suggesting new possibilities for treatment. Advancing our understanding of the molecular mechanisms that promote AML, especially how the bone marrow microenvironment affects invasion and drug resistance, is crucial. This comprehensive insight into the molecular and environmental interactions in AML emphasizes the need for ongoing research and more effective treatments.