Targeting stem cells in myelodysplastic syndromes and acute myeloid leukemia

miR-149-3p Enhances Drug Sensitivity of AML Cells by Inhibiting Warburg Effect Through PI3K/AKT Pathway

Acute myeloid leukemia (AML) is a kind of heterogeneous hematologic malignancy with high incidence, which is usually treated by intensive and maintenance treatment with large dose of conventional chemotherapy drugs. However, cell resistance is still an unsolved problem. The abnormal expression of miRNAs is closely related to the pathogenesis and progression of AML, and affects the drug resistance of cancer cells. miR-149-3p plays an important role in the resistance of cancer cells to cisplatin, and plays an excellent anti-tumor activity. By studying the function of miR-149-3p, it is expected to find new therapeutic methods to reverse chemotherapy resistance. In order to explore the mechanism of action of miR-149-3p on AML chemotherapeutic drug sensitivity, we explored the relationship between the Warburg effect and AML chemotherapeutic drug resistance. Based on AML cells, transfection of miR-149-3p inhibitor/NC and Warburg effect inhibitor (2DG) and PI3K/AKT pathway inhibitor (LY294002) were used to investigate the mechanism of IFN-γ regulating chemotherapy resistance of AML cells through Warburg effect. Down-regulation of miR-149-3p significantly inhibited drug sensitivity of AML cells. Down-regulation of miR-149-3p significantly promoted proliferation and invasion of AML cells while inhibiting apoptosis by up-regulating the expression of Bcl-2 and down-regulating the expression of Bax. Down-regulation of miR-149-3p significantly promoted the expression of Warburg effect-related proteins hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), and Glucose transporter 1 (GLUT1), glucose consumption, lactic acid, and intracellular ATP production. After inhibiting the Warburg effect with 2DG, the effect of miR-149-3p was inhibited, suggesting that upregulation of miR-149-3p reversed AML cell resistance by inhibiting the Warburg effect. In addition, miR-149-3p interacted with AKT1. Down-regulation of miR-149-3p increased the expression of inosine phosphate 3 kinase (PI3K), protein kinase B (AKT), and multi-drug resistance protein (MDR1). LY294002 inhibited the expression of these proteins, and down-regulation of miR-149-3p reversed the effect of LY294002 and improved the drug resistance of cells. Upregulation of miR-149-3p expression may potentially be a therapeutic target for AML resistance. It has been shown to inhibit PI3K/AKT pathway activation, thereby inhibiting the Warburg effect, and affecting cell proliferation, apoptosis, and drug resistance.

IL1RAP-specific T cell engager depletes acute myeloid leukemia stem cells

BACKGROUND

The interleukin-1 receptor accessory protein (IL1RAP) is highly expressed on acute myeloid leukemia (AML) bulk blasts and leukemic stem cells (LSCs), but not on normal hematopoietic stem cells (HSCs), providing an opportunity to target and eliminate the disease, while sparing normal hematopoiesis. Herein, we report the activity of BIF002, a novel anti-IL1RAP/CD3 T cell engager (TCE) in AML.

METHODS

Antibodies to IL1RAP were isolated from CD138+ B cells collected from the immunized mice by optoelectric positioning and single cell sequencing. Individual mouse monoclonal antibodies (mAbs) were produced and characterized, from which we generated BIF002, an anti-human IL1RAP/CD3 TCE using Fab arm exchange. Mutations in human IgG1 Fc were introduced to reduce FcγR binding. The antileukemic activity of BIF002 was characterized in vitro and in vivo using multiple cell lines and patient derived AML samples.

RESULTS

IL1RAP was found to be highly expressed on most human AML cell lines and primary blasts, including CD34+ LSC-enriched subpopulation from patients with both de novo and relapsed/refractory (R/R) leukemia, but not on normal HSCs. In co-culture of T cells from healthy donors and IL1RAPhigh AML cell lines and primary blasts, BIF002 induced dose- and effector-to-target (E:T) ratio-dependent T cell activation and leukemic cell lysis at subnanomolar concentrations. BIF002 administered intravenously along with human T cells led to depletion of leukemic cells, and significantly prolonged survival of IL1RAPhigh MOLM13 or AML patient-derived xenografts with no off-target side effects, compared to controls. Of note, BiF002 effectively redirects T cells to eliminate LSCs, as evidenced by the absence of disease initiation in secondary recipients of bone marrow (BM) from BIF002+T cells-treated donors (median survival not reached; all survived > 200 days) compared with recipients of BM from vehicle- (median survival: 26 days; p = 0.0004) or isotype control antibody+T cells-treated donors (26 days; p = 0.0002).

CONCLUSIONS

The novel anti-IL1RAP/CD3 TCE, BIF002, eradicates LSCs and significantly prolongs survival of AML xenografts, representing a promising, novel treatment for AML.

Phenolic Composition of Crataegus monogyna Jacq. Extract and Its Anti-Inflammatory, Hepatoprotective, and Antileukemia Effects

Crataegus monogyna (C. monogyna) is a prominent plant used in Moroccan traditional medicine. This study investigated the phenolic composition and the anti-inflammatory, the hepatoprotective, and the anticancer activities of a hydroethanolic extract of C. monogyna leaves and stems. Ultra-high-performance liquid chromatography identified the phenolic profile. The in vitro anticancer activity was evaluated using the MTT assay on HL-60 and K-562 myeloleukemia cells and liver (Huh-7) cell lines. The anti-inflammatory effect was assessed in vivo using carrageenan-induced paw edema in rats. The hepatoprotective effect at 300 and 1000 mg/kg doses against the acetaminophen-induced hepatotoxicity on rats was studied for seven days. Additionally, molecular docking simulations were performed to evaluate the extract's inhibitory potential against key targets: lipoxygenase, cytochrome P450, tyrosine kinase, and TRADD. The extract exhibited significant cytotoxic activity against K-562 and HL-60 cells, but not against lung cancer cells (Huh-7 line). The 1000 mg/kg dose demonstrated the most potent anti-inflammatory effect, inhibiting edema by 99.10% after 6 h. C. monogyna extract displayed promising hepatoprotective properties. Procyanidin (-7.27 kcal/mol), quercetin (-8.102 kcal/mol), and catechin (-9.037 kcal/mol) were identified as the most active molecules against lipoxygenase, cytochrome P450, and tyrosine kinase, respectively. These findings highlight the untapped potential of C. monogyna for further exploration in treating liver damage, inflammation, and leukemia.

Transcription elongation defects link oncogenic SF3B1 mutations to targetable alterations in chromatin landscape

Transcription and splicing of pre-messenger RNA are closely coordinated, but how this functional coupling is disrupted in human diseases remains unexplored. Using isogenic cell lines, patient samples, and a mutant mouse model, we investigated how cancer-associated mutations in SF3B1 alter transcription. We found that these mutations reduce the elongation rate of RNA polymerase II (RNAPII) along gene bodies and its density at promoters. The elongation defect results from disrupted pre-spliceosome assembly due to impaired protein-protein interactions of mutant SF3B1. The decreased promoter-proximal RNAPII density reduces both chromatin accessibility and H3K4me3 marks at promoters. Through an unbiased screen, we identified epigenetic factors in the Sin3/HDAC/H3K4me pathway, which, when modulated, reverse both transcription and chromatin changes. Our findings reveal how splicing factor mutant states behave functionally as epigenetic disorders through impaired transcription-related changes to the chromatin landscape. We also present a rationale for targeting the Sin3/HDAC complex as a therapeutic strategy.

Clinical decision-making and treatment of myelodysplastic syndromes

ABSTRACT

The myelodysplastic syndromes (MDSs) constitute a profoundly heterogeneous myeloid malignancy with a common origin in the hemopoietic stem cell compartment. Consequently, patient management and treatment are as heterogeneous. Decision-making includes identifying risk, symptoms, and options for an individual and conducting a risk-benefit analysis. The only potential cure is allogeneic stem cell transplantation, and albeit the fraction of patients with MDS who undergo transplant increase over time because of better management and increased donor availability, a majority are not eligible for this intervention. Current challenges encompass to decrease the relapse risk, the main cause of hematopoietic stem cell transplantation failure. Hypomethylating agents (HMAs) constitute firstline treatment for higher-risk MDSs. Combinations with other drugs as firstline treatment has, to date, not proven more efficacious than monotherapy, although combinations approved for acute myeloid leukemia, including venetoclax, are under evaluation and often used as rescue treatment. The treatment goal for lower-risk MDS is to improve cytopenia, mainly anemia, quality of life, and, possibly, overall survival. Erythropoiesis-stimulating agents (ESAs) constitute firstline treatment for anemia and have better and more durable responses if initiated before the onset of a permanent transfusion need. Treatment in case of ESA failure or ineligibility should be tailored to the main disease mechanism: immunosuppression for hypoplastic MDS without high-risk genetics, lenalidomide for low-risk del(5q) MDS, and luspatercept for MDS with ring sideroblasts. Approved therapeutic options are still scarcer for MDS than for most other hematologic malignancies. Better tools to match disease biology with treatment, that is, applied precision medicines are needed to improve patient outcome.

Novel precision medicine approaches and treatment strategies in hematological malignancies

Genetic testing has been applied for decades in clinical routine diagnostics of hematological malignancies to improve disease (sub)classification, prognostication, patient management, and survival. In recent classifications of hematological malignancies, disease subtypes are defined by key recurrent genetic alterations detected by conventional methods (i.e., cytogenetics, fluorescence in situ hybridization, and targeted sequencing). Hematological malignancies were also one of the first disease areas in which targeted therapies were introduced, the prime example being BCR::ABL1 inhibitors, followed by an increasing number of targeted inhibitors hitting the Achilles' heel of each disease, resulting in a clear patient benefit. Owing to the technical advances in high-throughput sequencing, we can now apply broad genomic tests, including comprehensive gene panels or whole-genome and whole-transcriptome sequencing, to identify clinically important diagnostic, prognostic, and predictive markers. In this review, we give examples of how precision diagnostics has been implemented to guide treatment selection and improve survival in myeloid (myelodysplastic syndromes and acute myeloid leukemia) and lymphoid malignancies (acute lymphoblastic leukemia, diffuse large B-cell lymphoma, and chronic lymphocytic leukemia). We discuss the relevance and potential of monitoring measurable residual disease using ultra-sensitive techniques to assess therapy response and detect early relapses. Finally, we bring up the promising avenue of functional precision medicine, combining ex vivo drug screening with various omics technologies, to provide novel treatment options for patients with advanced disease. Although we are only in the beginning of the field of precision hematology, we foresee rapid development with new types of diagnostics and treatment strategies becoming available to the benefit of our patients.

Sox13 and M2-like leukemia-associated macrophages contribute to endogenous IL-34 caused accelerated progression of acute myeloid leukemia

Interleukin 34 (IL-34) mainly plays physiologic and pathologic roles through the sophisticated multi-ligand signaling system, macrophage colony-stimulating factor (M-CSF, CSF-1)/IL-34-CSF-1R axis, which exhibits functional redundancy, tissue-restriction and diversity. This axis is vital for the survival, differentiation and function of monocytic lineage cells and plays pathologic roles in a broad range of diseases. However, the role of IL-34 in leukemia has not been established. Here MLL-AF9 induced mouse acute myeloid leukemia (AML) model overexpressing IL-34 (MA9-IL-34) was used to explore its role in AML. MA9-IL-34 mice exhibited accelerated disease progression and short survival time with significant subcutaneous infiltration of AML cells. MA9-IL-34 cells showed increased proliferation. In vitro colony forming assays and limiting dilution transplantation experiments demonstrated that MA9-IL-34 cells had elevated leukemia stem cell (LSC) levels. Gene expression microarray analysis revealed a panel of differential expressed genes including Sex-determining region Y (SRY)-box 13 (Sox13). Furthermore, a positive correlation between the expressions of IL-34 and Sox13 was detected human datasets. Knockdown of Sox13 rescued the enhanced proliferation, high LSC level and subcutaneous infiltration in MA9-IL-34 cells. Moreover, more leukemia-associated macrophages (LAMs) were detected in MA9-IL-34 microenvironment. Additionally, those LAMs showed M2-like phenotype since they expressed high level of M2-associated genes and had attenuated phagocytic potential, suggesting that LAMs should also contribute to IL-34 caused adverse phenotypes. Therefore, our findings uncover the intrinsic and microenvironmental mechanisms of IL-34 in AML and broadens the knowledge of M-CSF/IL-34-CSF-1R axis in malignancies.

Single-Cell Next-Generation Sequencing to Monitor Hematopoietic Stem-Cell Transplantation: Current Applications and Future Perspectives

Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) are genetically complex and diverse diseases. Such complexity makes challenging the monitoring of response to treatment. Measurable residual disease (MRD) assessment is a powerful tool for monitoring response and guiding therapeutic interventions. This is accomplished through targeted next-generation sequencing (NGS), as well as polymerase chain reaction and multiparameter flow cytometry, to detect genomic aberrations at a previously challenging leukemic cell concentration. A major shortcoming of NGS techniques is the inability to discriminate nonleukemic clonal hematopoiesis. In addition, risk assessment and prognostication become more complicated after hematopoietic stem-cell transplantation (HSCT) due to genotypic drift. To address this, newer sequencing techniques have been developed, leading to more prospective and randomized clinical trials aiming to demonstrate the prognostic utility of single-cell next-generation sequencing in predicting patient outcomes following HSCT. This review discusses the use of single-cell DNA genomics in MRD assessment for AML/MDS, with an emphasis on the HSCT time period, including the challenges with current technologies. We also touch on the potential benefits of single-cell RNA sequencing and analysis of accessible chromatin, which generate high-dimensional data at the cellular resolution for investigational purposes, but not currently used in the clinical setting.