miR-486 is involved in the pathogenesis of acute myeloid leukemia by regulating JAK-STAT signaling

Molecular insights and treatment innovations: Advancing outcomes in acute myeloid leukemia with myelodysplasia‑related changes (Review)

Acute myeloid leukemia, myelodysplasia‑related (AML‑MR), a challenging and aggressive subtype of AML, is characterized by unique genetic abnormalities and molecular features, which contribute to its poor prognosis compared with other AML subtypes. The present review summarizes the current understanding of AML‑MR pathogenesis, highlighting notable advancements in genetic and cytogenetic insights. Critical mutations, such as those in the tumor antigen p53 and additional sex combs like 1 genes, and their role in disease progression and resistance to treatment, are explored. The review further investigates how clonal evolution and cellular microenvironment alterations drive AML‑MR transformation and impact patient outcomes. Despite the poor outlook typically associated with AML‑MR, developments in treatment approaches offer hope. The present review considers the efficacy of novel therapeutic agents, including CPX‑351, hypomethylating agents and targeted molecular therapies. Additionally, innovations in immunotherapy and allogeneic hematopoietic stem cell transplantation are discussed as promising avenues to improve patient survival rates. The challenges of treating AML‑MR, particularly in elderly and pretreated patients, underline the necessity for individualized treatment strategies that consider both the biological complexity of the disease and the overall health profile of the patient. The present review focuses on the mechanisms of AML‑MR transformation, highlighting factors that may offer a crucial theoretical foundation and pave the way for future applications in precision medicine. Future research directions include exploring novel targeted therapies and combination regimens to mitigate the transformation risks and enhance the quality of life of patients with AML‑MR.

miR-186-5p Down-Regulates PD-L1 Level in Acute Myeloid Leukemia Cells and Inhibits Tumorigenesis and Immune Escape

Acute myeloid leukemia (AML) is a malignant tumor of blood cells, which seriously interferes with the generation of normal cells. Although miR-186-5p is diminished in AML, its exact mechanism is not well understood. miR-186-5p and PD-L1 levels in AML cells (HL-60, KG-1, TF-1a, MOLT-3) and subcutaneous tumor tissue were discovered through qRT-PCR and Western blot. miR-186-5 p and PD-L1 combining sites were foreseen by the database and verified by dual luciferase and immunoprecipitation experiments. AML cells with miR-186-5p overexpression or knockdown and PD-L1 overexpression were cocultured with CD4+ and CD8+ T cells. The proliferation, migration, invasion and apoptosis of AML cells, CD8+ and CD4+ T cell growth and apoptosis, and activated markers (Perforin and Granzyme B) and secreted cytokines (IFN-γ, IL-4 and TNF-α) levels were detected by CCK8, Transwell, flow cytometry, CFSE, Western blot and ELISA, respectively. Subcutaneous xenograft magnitude and mass in nude mice were measured. Ki67 level was identified through immunohistochemistry. CD4+ and CD8+ T cell level and infiltration were detected by immunofluorescence and flow cytometry. miR-186-5p was downregulated, and PD-L1 was boosted in AML cells and subcutaneous tumor tissues (p < 0.05), while miR-186-5p targeted down-regulate PD-L1. miR-186-5p upregulation hindered AML cell multiplication, migration, invasion and facilitate cell death, and enhanced the proliferation activity, activation markers (Perforin and Granzyme B) and secreted cytokines (IFN-γ, IL-4, TNF-α) of CD8+ and CD4+ T cells, inhibited apoptosis, and inhibited immune escape (p < 0.05). Knockdown of miR-186-5p can promote AML progression, but PD-L1 upregulation weakens the antitumor impact of miR-186-5p overexpression (p < 0.05). Transplanted tumor mice experiments also found that miR-186-5p hindered PD-L1 and tumor growth (p < 0.05). In conclusion, miR-186-5p can target inhibit PD-L1, suppress AML cells multiplication, movement, invasion and immune escape, and then reduce AML, aiming to provide support and basis for the pathological mechanism and prevention and treatment strategy of AML.

Effect of AML-exosomes on the cellular and molecular properties of bone marrow mesenchymal stromal cells: Expression of JAK/STAT signaling genes

PURPOSE OF STUDY

Despite the various therapeutic options introduced for AML treatment, therapy resistance and relapse are still the main obstacles. It is well known that alterations in the bone marrow microenvironment (BMM) play a crucial role in leukemia growth and the treatment failure of AML. Evidence shows that exosomes alter the components of BMM in a way that support leukemia survival, leading to chemoresistance. In this study, we evaluated the effect of AML exosomes on the biological functions of human bone marrow mesenchymal stromal cells (h BM-MSCs), especially alteration in the expression of the JAK/STAT signaling genes, as a leukemia-favoring pathway.

METHOD

Exosomes were isolated from the HL-60 cell line and characterized using flow cytometry, Transmission Electron Microscopy (TEM), and Dynamic Light Scattering (DLS) technique. The exosome protein content was assessed using a bicinchoninic acid (BCA) protein assay kit in order to determine the concentration of exosomes. Subsequently, MSCs were treated with varying concentrations of AML exosomes, and data was obtained using MTT, cell cycle, apoptosis, and ki67 assays. Additionally, gene expression analysis was conducted through qRT-PCR.

RESULT

AML exosomes regulated the viability and survival of MSCs in a concentration-dependent manner. The qRT-PCR data revealed that treatment with AML exosomes at a concentration of 50 μg/mL led to a significant upregulation of JAK2, STAT3, and STAT5 genes in MSCs.

CONCLUSION

Because the JAK/STAT signaling pathway has been shown to play a role in the proliferation and survival of leukemic cells, our results suggest that AML exosomes stimulate MSCs to activate this pathway. This activation may impede AML cell apoptosis, potentially leading to chemoresistance and relapse.

Bone marrow mesenchymal stem cell exosomes suppress JAK/STAT signaling pathway in acute myeloid leukemia in vitro

INTRODUCTION

Despite advances in the treatment of acute myeloid leukemia (AML), refractory forms of this malignancy and relapse remain common. Therefore, development of novel, synergistic targeted therapies are needed urgently. Recently, mesenchymal stem cells (MSCs) have been shown to be effective in treating various diseases, with most of their therapeutic outcomes attributed to their exosomes. In the current study, we investigated the effects of bone marrow mesenchymal stem cell (BM-MSC) exosomes on the expression of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling genes involved in AML pathogenesis.

MATERIAL AND METHODS

Exosomes were isolated from BM-MSCs and confirmed using transmission electron microscopy, dynamic light scattering, and flow cytometry. Subsequently, the exosome concentration was estimated using the bicinchoninic acid assay, and HL-60 cells were cocultured with 100 µg/mL of BM-MSC exosomes. Finally, the JAK2, STAT3, and STAT5 expression levels were analyzed using qRT-PCR.

RESULTS

The exosome characterization results confirmed that most isolated nanoparticles exhibited a round morphology, expressed CD9, CD63, and CD81, which are specific protein markers for exosome identification, and ranged between 80 and 100 nm in diameter. Furthermore, qRT-PCR analysis revealed a significant downregulation of JAK2, STAT3, and STAT5 in HL-60 cells treated with 100 μg/mL of BM-MSC exosomes.

CONCLUSION

Since JAK/STAT signaling contributes to AML survival, our findings suggest that the downregulation of JAK/STAT genes by BM-MSC exosomes in leukemic cells may aid in designing a potent therapeutic strategy for AML treatment.

High expression of malic enzyme 1 predicts adverse prognosis in patients with cytogenetically normal acute myeloid leukaemia and promotes leukaemogenesis through the IL-6/JAK2/STAT3 pathways

Background

Progress in improving risk stratification methods for patients with cytogenetically normal acute myeloid leukaemia (CN-AML) remains limited. This study investigates the prognostic significance and potential functional mechanism of malic enzyme 1 (ME1) in CN-AML.

Methods

Gene expression and clinical data of patients with CN-AML were obtained from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets, which were subjected to analysis. The prognostic significance of ME1 was assessed through Kaplan-Meier survival analysis, as well as univariate and multivariate Cox regression analyses. A novel risk model based on ME1 expression levels was developed using TCGA data for predicting CN-AML prognosis. Furthermore, the impact of ME1 silencing on AML cell lines was investigated using the Cell Counting Kit-8 assay and flow cytometry. Gene set enrichment analysis (GSEA) analysis and Western blotting were performed to explore the mechanism of ME1 in CN-AML.

Results

CN-AML patients expressing higher ME1 levels exhibited shorter event-free survival (EFS) and overall survival (OS) compared to those with lower ME1 expression in the TCGA and multiple GEO datasets (all p < 0.05). Univariate and multivariate Cox regression analyses indicated that ME1 expression served as an independent prognostic factor for the EFS (p = 0.024 in TCGA, p = 0.035 in GSE6891) and OS (p = 0.039 in TCGA, p = 0.008 in GSE6891) in patients with CN-AML. The developed risk model demonstrated that patients with CN-AML in the high-risk group had worse survival than those in the low-risk group (hazard ratio: 2.67, 95% confidence interval: 1.54-4.65, p < 0.001) and exhibited strong predictive accuracy for 1-, 3- and 5-year OS (area under the curve = 0.69, 0.75, 0.79, respectively). ME1 knockdown significantly inhibited proliferation and increased apoptosis in AML cells (all p < 0.05). GSEA and Western blotting demonstrated that ME1 regulates the IL-6/JAK2/STAT3 pathway in CN-AML.

Conclusion

Elevated ME1 expression serves as an indicator of poorer prognosis in patients with CN-AML, potentially facilitating leukaemogenesis through the IL-6/JAK2/STAT3 pathway. This suggests that ME1 could be a promising prognostic biomarker and therapeutic target for CN-AML.

Artesunate reverses cytarabine resistance in acute myeloid leukemia by blocking the JAK/STAT3 signaling

OBJECTIVES

Although cytarabine (AraC) has greatly contributed to improving the prognosis of patients with acute myeloid leukemia (AML), many patients developed drug resistance and eventually succumbed to AML. Thus, resistance to AraC is a major obstacle to improve the efficacy of chemotherapy in AML. Hence, this study aimed to demonstrate that artesunate (ART) can reliably induce cell death in vitro and block AraC resistance.

METHODS

AML cell lines resistant to AraC were first constructed by repeated dosing for 5 months. Further, we analyzed whether ART intervention affected the sensitivity of AraC-resistant cells to AraC by cell function experiments, mainly including CCK-8 to assess cell viability, flow cytometry to examine apoptosis, and Western blotting to measure the Janus kinase (JAK)/signal transducers and activators of transcription 3 (STAT3) pathway protein expression. Furthermore, whether JAK/STAT3 pathway knockdown has a blocking effect on the efficacy of ART was also assessed.

RESULTS

Co-treatment of ART and AraC increased the sensitivity of AML cells to AraC. Also, it effectively reversed the resistance of AML cells to AraC that is shown by the significantly reduced proliferation and increased apoptosis rates. ART intervention suppressed the activation of the JAK/STAT3 signaling pathway in AraC-resistant AML cells, suggesting that the function of ART in reversing AraC resistance is indeed dependent on the JAK/STAT3 signaling pathway.

CONCLUSIONS

In summary, ART enhanced the sensitivity of AML/AraC-resistant cells to AraC by modulating the JAK/STAT3 pathway.

Multiomics to investigate the mechanisms contributing to repression of PTPRC and SOCS2 in pediatric T-ALL: Focus on miR-363-3p and promoter methylation

T-cell acute lymphoblastic leukemia (T-ALL) is a heterogeneous and aggressive malignancy arising from T-cell precursors. MiRNAs are implicated in negative regulation of gene expression and when aberrantly expressed contribute to various cancer types, including T-ALL. Previously we demonstrated the oncogenic potential of miR-363-3p overexpression in a subgroup of T-ALL patients. Here, using combined proteomic and transcriptomic approaches, we show that miR-363-3p enhances cell growth of T-ALL in vitro via inhibition of PTPRC and SOCS2, which are implicated in repression of the JAK-STAT pathway. We propose that overexpression of miR-363-3p is a novel mechanism potentially contributing to overactivation of JAK-STAT pathway. Additionally, by combining the transcriptomic and methylation data of T-ALL patients, we show that promoter methylation may also contribute to downregulation of SOCS2 expression and thus potentially to JAK-STAT activation. In conclusion, we highlight aberrant miRNA expression and aberrant promoter methylation as mechanisms, alternative to mutations of JAK-STAT-related genes, which might lead to the upregulation of JAK-dependent signaling in T-ALL.

microRNA expression in acute myeloid leukaemia: New targets for therapy?

Recent studies have shown that short non-coding RNAs, known as microRNAs (miRNAs) and their dysregulation, are implicated in the pathogenesis of acute myeloid leukaemia (AML). This is due to their role in the control of gene expression in a variety of molecular pathways. Therapies involving miRNA suppression and replacement have been developed. The normalisation of expression and the subsequent impact on AML cells have been investigated for some miRNAs, demonstrating their potential to act as therapeutic targets. Focussing on miRs with therapeutic potential, we have reviewed those that have a significant impact on the aberrant biological processes associated with AML, and crucially, impact leukaemic stem cell survival. We describe six miRNAs in preclinical trials (miR-21, miR-29b, miR-126, miR-181a, miR-223 and miR-196b) and two miRNAs that are in clinical trials (miR-29 and miR-155). However none have been used to treat AML patients and greater efforts are needed to develop miRNA therapies that could benefit AML patients in the future.

Neuron secrete exosomes containing miR-9-5p to promote polarization of M1 microglia in depression

Background

Neuroinflammation is an important component mechanism in the development of depression. Exosomal transfer of MDD-associated microRNAs (miRNAs) from neurons to microglia might exacerbate neuronal cell inflammatory injury.

Results

By sequence identification, we found significantly higher miR-9-5p expression levels in serum exosomes from MDD patients than healthy control (HC) subjects. Then, in cultured cell model, we observed that BV2 microglial cells internalized PC12 neuron cell-derived exosomes while successfully transferring miR-9-5p. MiR-9-5p promoted M1 polarization in microglia and led to over releasing of proinflammatory cytokines, such as interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), which exacerbated neurological damage. Furthermore, we identified suppressor of cytokine signaling 2 (SOCS2) as a direct target of miR-9-5p. Overexpression of miR-9-5p suppressed SOCS2 expression and reactivated SOCS2-repressed Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathways. Consistently, we confirmed that adeno-associated virus (AAV)-mediated overexpression of miR-9-5p polarized microglia toward the M1 phenotype and exacerbated depressive symptoms in chronic unpredictable mild stress (CUMS) mouse mode.

Conclusion

MiR-9-5p was transferred from neurons to microglia in an exosomal way, leading to M1 polarization of microglia and further neuronal injury. The expression and secretion of miR-9-5p might be novel therapeutic targets for MDD.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01332-w.

A Role for the Bone Marrow Microenvironment in Drug Resistance of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease with a poor prognosis and remarkable resistance to chemotherapeutic agents. Understanding resistance mechanisms against currently available drugs helps to recognize the therapeutic obstacles. Various mechanisms of resistance to chemotherapy or targeted inhibitors have been described for AML cells, including a role for the bone marrow niche in both the initiation and persistence of the disease, and in drug resistance of the leukemic stem cell (LSC) population. The BM niche supports LSC survival through direct and indirect interactions among the stromal cells, hematopoietic stem/progenitor cells, and leukemic cells. Additionally, the BM niche mediates changes in metabolic and signal pathway activation due to the acquisition of new mutations or selection and expansion of a minor clone. This review briefly discusses the role of the BM microenvironment and metabolic pathways in resistance to therapy, as discovered through AML clinical studies or cell line and animal models.

The Emerging Role of Suppressors of Cytokine Signaling (SOCS) in the Development and Progression of Leukemia

Cytokines are pleiotropic signaling molecules that execute an essential role in cell-to-cell communication through binding to cell surface receptors. Receptor binding activates intracellular signaling cascades in the target cell that bring about a wide range of cellular responses, including induction of cell proliferation, migration, differentiation, and apoptosis. The Janus kinase and transducers and activators of transcription (JAK/STAT) signaling pathways are activated upon cytokines and growth factors binding with their corresponding receptors. The SOCS family of proteins has emerged as a key regulator of cytokine signaling, and SOCS insufficiency leads to constitutive activation of JAK/STAT signaling and oncogenic transformation. Dysregulation of SOCS expression is linked to various solid tumors with invasive properties. However, the roles of SOCS in hematological malignancies, such as leukemia, are less clear. In this review, we discuss the recent advances pertaining to SOCS dysregulation in leukemia development and progression. We also highlight the roles of specific SOCS in immune cells within the tumor microenvironment and their possible involvement in anti-tumor immunity. Finally, we discuss the epigenetic, genetic, and post-transcriptional modifications of SOCS genes during tumorigenesis, with an emphasis on leukemia.