Extracellular vesicles carrying miRNA-181b-5p affects the malignant progression of acute lymphoblastic leukemia

Hierarchical DNA Octahedral Nanoplatform for in Situ Biosensing and Clinical Monitoring of Acute Lymphoblastic Leukemia

Developing nanoscale platforms with high integration, assembly efficiency, and structural stability for performing complex computations in specific cells remains a significant challenge. To address this, the Three-dimensional Hierarchical Octahedral Robotic (THOR) DNA nanoplatform is introduced, which integrates targeting, logic computation, and sensing modules within a single framework. This nanoplatform specifically binds to cancer cell surface proteins, releasing aptamer-linked fuel chains to initiate subsequent computational processes. Three logic gates efficiently compute any arbitrary binary combination of target proteins. The sensing module employs catalytic hairpin assembly for detecting specific miRNAs with high sensitivity. THOR demonstrates robust functionality both in vitro and in situ. As a proof-of-concept, this nanoplatform to distinguish acute lymphoblastic leukemia (ALL) patients from other leukemia subtypes and healthy participants, achieving 100% accuracy is applied. Additionally, this approach reliably monitored the therapeutic progress of ALL patients, showing strong concordance with bone marrow smear results. The THOR platform highlights the feasibility of constructing a reliable, hierarchical, and multifunctional analytical system based on a single DNA polyhedron. It offers a promising auxiliary tool for clinical diagnostics and therapeutic monitoring.

Harnessing the power of exosomes for diagnosis, prognosis, and treatment of hematological malignancies

Exosomes are small extracellular vesicles of endocytic origin released by various cell types. They consist of lipid bilayers containing macromolecules such as lipids, proteins, microRNAs, growth factors, cytokines, and carbohydrates. Exosomes play a critical role in the diagnosis and treatment of various diseases. For instance, exosome contents have been utilized as biomarkers in body fluids (urine, saliva, serum) to identify cancers, autoimmune diseases, and inflammatory conditions such as sepsis. Due to their small size and ability to reach tumor microenvironments, exosomes are also used as carriers for chemotherapeutic drugs in drug delivery systems. Furthermore, evidence indicates that malignant cells release exosomes into the tumor microenvironment, influencing immune cells in a paracrine manner. Additionally, immune cell-derived exosomes, such as those from Natural Killer (NK) cells or cytotoxic T lymphocytes (CTLs), show potential as therapeutic agents in treating malignancies like leukemia. This review discusses the diagnostic role of exosomes in various hematological malignancies and explores the therapeutic potential of immune cell-derived exosomes in these diseases.

Potential Use of Exosomal Non-Coding MicroRNAs in Leukemia Therapy: A Systematic Review

Leukemia is a heterogeneous group of hematological malignancies. Despite the enormous progress that has been made in the field of hemato-oncology in recent years, there are still many problems related to, among others, disease recurrence and drug resistance, which is why the search for ideal biomarkers with high clinical utility continues. Research shows that exosomes play a critical role in the biology of leukemia and are associated with the drug resistance, metastasis, and immune status of leukemias. Exosomes with their cargo of non-coding RNAs act as a kind of intermediary in intercellular communication and, at the same time, have the ability to manipulate the cell microenvironment and influence the reaction, proliferative, angiogenic, and migratory properties of cells. Exosomal ncRNAs (in particular, circRNAs and microRNAs) appear to be promising cell-free biomarkers for diagnostic, prognostic, and treatment monitoring of leukemias. This review examines the expression of exosomal ncRNAs in leukemias and their potential regulatory role in leukemia therapy but also in conditions such as disease relapse, drug resistance, metastasis, and immune status. Given the key role of ncRNAs in regulating gene networks and intracellular pathways through their ability to interact with DNA, transcripts, and proteins and identifying their specific target genes, defining potential functions and therapeutic strategies will provide valuable information.

Dual roles of extracellular vesicles in acute lymphoblastic leukemia: implications for disease progression and theranostic strategies

Acute Lymphoblastic Leukemia (ALL) is a heterogeneous blood cancer characterized by the uncontrolled growth of immature lymphoid cells due to dysregulated signaling pathways. It is the most common pediatric cancer, with high cure rates in children, but significantly lower survival rates in adults. Current theranostic strategies, including chemotherapy, immunotherapy, and nanomedicine, aim to improve detection and treatment precision but are limited by side effects, drug resistance, high costs, and stability issues. Notably, extracellular vesicles (EVs) offer a promising alternative, addressing these limitations through their natural biocompatibility and targeted delivery capabilities. EVs play a dual role in ALL: they contribute to leukemia progression by promoting tumor growth, immune suppression, and drug resistance via the transfer of oncogenic molecules, while also serving as valuable non-invasive biomarkers due to their specific miRNA and protein content. Their ability to deliver therapeutic agents directly to leukemic cells, combined with their stability and low immunogenicity, makes EVs a compelling tool for improving ALL treatments. Indeed, by targeting the molecular pathways influenced by EVs or leveraging them for drug delivery, innovative therapeutic strategies can be developed to enhance treatment outcomes and reduce side effects. Thus, EVs represent a promising frontier for advancing theranostic strategies in ALL, offering new opportunities to improve diagnosis and treatment while overcoming the limitations of traditional therapies. This review will explore the dual roles of EVs in ALL, addressing their contributions to disease progression and their potential as therapeutic agents and biomarkers for early diagnosis and targeted therapies.

Recent Progress of Exosomes in Hematological Malignancies: Pathogenesis, Diagnosis, and Therapeutic Strategies

Hematological malignancies originate from the hematopoietic system, including lymphoma, multiple myeloma, leukaemia, etc. They are highly malignant with a high incidence, a poor prognosis and a high mortality. Although the novel therapeutic strategies have partly improved the clinical efficacy of hematological malignancies, patients still face up with drug resistance, refractory disease and disease relapse. Many studies have shown that exosomes play an important role in hematological malignancies. Exosomes are nanoscale vesicles secreted by cells with a size ranging from 40 to 160 nm. They contain various intracellular components such as membrane proteins, lipids, and nucleic acids. These nanoscale vesicles transmit information between cells with the cargos. Thus, they participate in a variety of pathological processes such as angiogenesis, proliferation, metastasis, immunomodulation and drug resistance, which results in important role in the pathogenesis and progression of hematological malignancies. Furthermore, exosomes and the components carried in them can be used as potential biomarkers for the diagnosis, therapeutic sensitivity and prognosis in hematological malignancies. In the therapy of hematologic malignancies, certain exosome are potential to be used as therapeutic targets, meanwhile, exosomes are suitable drug carriers with lipid bilayer membrane and the nanostructure. Moreover, the tumor-derived exosomes of patients with hematologic malignancies can be developed into anti-tumor vaccines. The research and application of exosomes in hematological malignancies are summarized and discussed in this review.

Anticancer effects of pomegranate-derived peptide PG2 on CDK2 and miRNA-339-5p-mediated apoptosis via extracellular vesicles in acute leukemia

Acute leukemia has rapid onset and severe complications. Anticancer peptides from natural sources have demonstrated efficacy in eliminating various cancers through apoptosis signaling pathways. Additionally, extracellular vesicles containing microRNAs play pivotal roles in promoting tumorigenesis. Therefore, this study aimed to investigate the impact of PG2, a pomegranate peptide that regulates extracellular vesicles, on the induction of acute leukemia cell apoptosis. NB4 and MOLT-4 leukemia cell lines were treated with PG2 alone or in combination with daunorubicin to assess cell viability using the MTT assay. Extracellular vesicles were extracted from PG2-treated NB4 and MOLT-4 cells. Bioinformatic tools were utilized to predict target proteins and microRNAs, following which mRNA and protein expression were determined by using RT‒qPCR and western blotting, respectively. PG2 significantly reduced the viability of NB4 and MOLT-4 cells. Furthermore, the combination of PG2 with daunorubicin had a synergistic effect on NB4 and MOLT-4 cells. Subsequent treatment with PG2 or PG2-treated extracellular vesicles decreased CDK2 expression while increasing microRNA-339-5p and caspase-3 expression in NB4 and MOLT-4 cells. Our findings revealed that the anticancer activity of PG2 through the CDK2/miR-339-5p/caspase-3 pathway is mediated by extracellular vesicles, ultimately inducing apoptosis. PG2 holds promise as a potential antileukemic drug.

Single-cell RNA-seq analysis revealed the stemness of a specific cluster of B cells in acute lymphoblastic leukemia progression

Background

Childhood acute lymphoblastic leukemia (ALL) is a common pediatric cancer. The heterogeneous characterization of B cells in ALL progression poses new challenges to researchers. We used single-cell sequencing to explore the critical role of B cells in regulating the ALL immune microenvironment.

Method

We collected the single cell (sc) RNA-seq data of ALL and health sample from the gene expression omnibus (GEO) database, the "Seurat" and "harmony" R package was used for quality control and scRNA-seq analysis, in which the CellMarker2.0 database was used for cell type annotation. Subsequently, the FindAllMarkers function was used to identify the differentially expressed genes (DEGs) among various cell types and the DAVID database was applied for the biological process of DEGs. Then, the "inferCNV" package was used for copy number variation, regulons and cell communication were performed by SCENIC tool and CellChat package. The role of the target gene in regulating ALL progression was assessed using RT-qPCR, Transwell and scratch healing assays.

Results

We identified nine mainly cell clusters after scRNA-seq analysis, in which the B cells had higher infiltration proportion in the ALL samples and were sub-clustered into five cell sub-groups. The B cells 1 is closely associated with cell proliferation and stemness (TNFAIP3 and KDM5B), and the significant CNV of amplification occurred on chr6 and chr21 that supported stemness of B cells1. RXRB is a key transcription factor mediated the proliferation of B cells 1, which in turn suppressed hematopoietic stem cells (HSCs) proliferation and promoted cytotoxic NK/T cells activation through diverse cell communication ways. One of the key regulators of B cells is MYC, which promotes the migration and invasive ability of cell line leukemia cell lines.

Conclusion

This study reveals the stemness characteristics of B cells and their critical role in ALL progression, a finding that provides new potential directions for the development of targeted therapies against ALL.

Advancements in Personalized CAR-T Therapy: Comprehensive Overview of Biomarkers and Therapeutic Targets in Hematological Malignancies

Chimeric antigen receptor T-cell (CAR-T) therapy is a novel anticancer therapy using autologous or allogeneic T-cells. To date, six CAR-T therapies for specific B-cell acute lymphoblastic leukemia (B-ALL), non-Hodgkin lymphomas (NHL), and multiple myeloma (MM) have been approved by the Food and Drug Administration (FDA). Significant barriers to the effectiveness of CAR-T therapy include cytokine release syndrome (CRS), neurotoxicity in the case of Allogeneic Stem Cell Transplantation (Allo-SCT) graft-versus-host-disease (GVHD), antigen escape, modest antitumor activity, restricted trafficking, limited persistence, the immunosuppressive microenvironment, and senescence and exhaustion of CAR-Ts. Furthermore, cancer drug resistance remains a major problem in clinical practice. CAR-T therapy, in combination with checkpoint blockades and bispecific T-cell engagers (BiTEs) or other drugs, appears to be an appealing anticancer strategy. Many of these agents have shown impressive results, combining efficacy with tolerability. Biomarkers like extracellular vesicles (EVs), cell-free DNA (cfDNA), circulating tumor (ctDNA) and miRNAs may play an important role in toxicity, relapse assessment, and efficacy prediction, and can be implicated in clinical applications of CAR-T therapy and in establishing safe and efficacious personalized medicine. However, further research is required to fully comprehend the particular side effects of immunomodulation, to ascertain the best order and combination of this medication with conventional chemotherapy and targeted therapies, and to find reliable predictive biomarkers.

ActivinA modulates B-acute lymphoblastic leukaemia cell communication and survival by inducing extracellular vesicles production

Extracellular vesicles (EVs) are a new mechanism of cellular communication, by delivering their cargo into target cells to modulate molecular pathways. EV-mediated crosstalk contributes to tumor survival and resistance to cellular stress. However, the role of EVs in B-cell Acute Lymphoblastic Leukaemia (B-ALL) awaits to be thoroughly investigated. We recently published that ActivinA increases intracellular calcium levels and promotes actin polymerization in B-ALL cells. These biological processes guide cytoskeleton reorganization, which is a crucial event for EV secretion and internalization. Hence, we investigated the role of EVs in the context of B-ALL and the impact of ActivinA on this phenomenon. We demonstrated that leukemic cells release a higher number of EVs in response to ActivinA treatment, and they can actively uptake EVs released by other B-ALL cells. Under culture-induced stress conditions, EVs coculture promoted cell survival in B-ALL cells in a dose-dependent manner. Direct stimulation of B-ALL cells with ActivinA or with EVs isolated from ActivinA-stimulated cells was even more effective in preventing cell death. This effect can be possibly ascribed to the increase of vesiculation and modifications of EV-associated microRNAs induced by ActivinA. These data demonstrate that ActivinA boosts EV-mediated B-ALL crosstalk, improving leukemia survival in stress conditions.

MDSCs in bone metastasis: Mechanisms and therapeutic potential

Bone metastasis (BM) is a frequent complication associated with advanced cancer that significantly increases patient mortality. Myeloid-derived suppressor cells (MDSCs) play a pivotal role in BM progression by promoting angiogenesis, inhibiting immune responses, and inducing osteoclastogenesis. MDSCs induce immunosuppression through diverse mechanisms, including the generation of reactive oxygen species, nitric oxide, and immunosuppressive cytokines. Within the bone metastasis niche (BMN), MDSCs engage in intricate interactions with tumor, stromal, and bone cells, thereby establishing a complex regulatory network. The biological activities and functions of MDSCs are regulated by the microenvironment within BMN. Conversely, MDSCs actively contribute to microenvironmental regulation, thereby promoting BM development. A comprehensive understanding of the indispensable role played by MDSCs in BM is imperative for the development of novel therapeutic strategies. This review highlights the involvement of MDSCs in BM development, their regulatory mechanisms, and their potential as viable therapeutic targets.

Disruption of the Hippo pathway promotes the proliferation of childhood acute lymphoblastic leukemia cells, inhibits apoptosis and chemosensitivity

BACKGROUND

Despite advancements in chemotherapy and stem cell transplantation, the recurrence and chemoresistance of childhood acute lymphoblastic leukemia (cALL) remain a significant challenge, thus indicating the need for novel therapeutic targets.

RESEARCH DESIGN AND METHODS

The protein levels of YAP1, p-YAP1, TAZ, and Cyr61 of cALL patients and healthy volunteers were measured by western blot analysis. Then the leukemic cell line SUP-B15 was transfected with sh-YAP1 and pcDNA3.1-YAP1 to knockdown or overexpress YAP1. The viability, chemosensitivity, apoptosis, migration, and invasion of SUP-B15 cells were determined by MTT, flow cytometry, and Transwell assay.

RESULTS

The cALL patients had higher YAP1, TAZ, and Cyr61 protein expression and lower p-YAP1 protein expression in bone marrow tissues compared with healthy volunteers (p < 0.01). In SUP-B15 cells, YAP1 knockdown upregulated p-YAP1 protein expression (p < 0.01) and downregulated TAZ and Cyr61 protein expression (p < 0.01). In addition, knocking down YAP1 significantly inhibited cell viability, migration, and invasion, and induced apoptosis (p < 0.01). YAP1 knockdown also reduced the IC50 value following treatment with vincristine, daunorubicin, cyclophosphamide, and dexamethasone (p < 0.05).

CONCLUSIONS

Disruption of the Hippo pathway attenuates the development of cALL by promoting cell proliferation while suppressing apoptosis and drug sensitivity.

COVID-19 in patients with anemia and haematological malignancies: risk factors, clinical guidelines, and emerging therapeutic approaches

Extensive research in countries with high sociodemographic indices (SDIs) to date has shown that coronavirus disease 2019 (COVID-19) may be directly associated with more severe outcomes among patients living with haematological disorders and malignancies (HDMs). Because individuals with moderate to severe immunodeficiency are likely to undergo persistent infections, shed virus particles for prolonged periods, and lack an inflammatory or abortive phase, this represents an overall risk of morbidity and mortality from COVID-19. In cases suffering from HDMs, further investigation is needed to achieve a better understanding of triviruses and a group of related variants in patients with anemia and HDMs, as well as their treatment through vaccines, drugs, and other methods. Against this background, the present study aimed to delineate the relationship between HDMs and the novel COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Besides, effective treatment options for HDM cases were further explored to address this epidemic and its variants. Therefore, learning about how COVID-19 manifests in these patients, along with exploiting the most appropriate treatments, may lead to the development of treatment and care strategies by clinicians and researchers to help patients recover faster. Video Abstract.

miR-539-5p targets BMP2 to regulate Treg activation in B-cell acute lymphoblastic leukemia through TGF-β/Smads/MAPK

MicroRNAs (mRNAs) were believed to play an important role in cancers, and this study aimed to explore the mechanism of miRNA regulating Treg in B-cell acute lymphoblastic leukemia (B-ALL). Firstly, the differentially expressed miRNAs and target genes significantly associated with Tregs were screened out by high-throughput sequencing, and their enrichment pathways were analyzed. The binding relationship between miRNA and target genes was further verified, and the effects of miRNA on the proliferation and apoptosis of B-ALL Nalm-6 cells and Treg activation were analyzed. Results showed that differentially expressed miR-539-5p was significantly under-expressed, and its target gene BMP2 was significantly over-expressed in B-ALL, and significantly enriched in the TGF-β1 pathway. In addition, both miR-539-5p and BMP2 were significantly correlated with Treg activity in B-ALL. In vitro experiments further confirmed that miR-539-5p could directly target BMP2. The low expression of miR-539-5p in B-ALL significantly promoted BMP2 expression to promote the proliferation and inhibit apoptosis of Nalm-6 cells. Furthermore, the high expression of BMP2 in B-ALL could cooperate with TGF-β1 to promote the activation of human CD4+CD25-T cells to Treg, and significantly activate the TGF-β/Smads/MAPK pathway. In vivo experiments also confirmed that overexpression of miR-539-5p significantly inhibited BMP2 to suppress Treg activation and Smad1 and Smad2 phosphorylation, and finally inhibit the B-ALL process. In conclusion, miR-539-5p was significantly under-expressed in B-ALL and could target BMP2 to promote its expression, and the overexpressed BMP2 further promoted Treg activation in B-ALL by regulating TGF-β/Smads/MAPK pathway.

A novel therapeutic strategy: the significance of exosomal miRNAs in acute myeloid leukemia

Acute myeloid leukemia (AML) is a fast-growing blood cancer that interferes with the normal growth of blood cells in the bone marrow and blood. It is characterized by its unpredictable outlook and high death rate. The main treatment for AML is chemotherapy, but this often results in drug resistance and the possibility of the disease returning. For this reason, new biomarkers are necessary to diagnose, predict, and treat this disease. Research has demonstrated that cells responsible for AML release exosomes that interact with the disease's microenvironment. These exosomes have significant roles in promoting leukemia growth, suppressing normal hematopoiesis, facilitating angiogenesis, and contributing to drug resistance in AML. Further investigations have shown that these exosomes contain miRNAs, which are transferred to target cells and have functional roles. Biomarkers are utilized to assess various aspects of tumor cell behavior, including proliferation, apoptosis, angiogenesis, changes in the microenvironment, transfer of drug resistance, and stability in serum and blood plasma. In this research, we showed that exosomal miRNAs and exosomes have the potential to be used as indicators for detecting various phases of AML and can aid in its medical treatment. Furthermore, they can be specifically targeted for therapeutic purposes in addressing this condition.

Plasma-derived exosomal miR-326, a prognostic biomarker and novel candidate for treatment of drug resistant pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a cancer with high incidence rate in pediatrics and drug resistance is a major clinical concern for ALL treatment. The current study was designed to evaluate the role of exosomal miR-326 in diagnosis and treatment of children with B-ALL. Exosomes were isolated from plasma samples of 30 patients and B-ALL cell lines followed by characterization, using nanoparticle tracking analysis, immunoblotting assay and electron microscopy. qPCR showed significantly increased levels of miR-326 in patients exosomes compared with non-cancer controls (P < 0.05, AUC = 0.7500). Moreover, a comparison between the sensitive and drug resistant patients revealed a prognostic value for the exosomal miR326 (P < 0.05, AUC = 0.7755). Co-culture studies on drug resistant patient primary cells and B-ALL cell lines suggested that exosomes with high miR-326 level act as vehicles for reducing cells viability. B-ALL cell line transfection with naked miR-326 mimic confirmed the results, and fluorescence microscopy validated uptake and internalization of exosomes by target cells. The novel introduced features of the exosomal miR-326 address a non-invasive way of diagnosing primary drug resistance in pediatric ALL and advocates a novel therapeutic strategy for this cancer.

Advancements in the Regulatory Role of microRNAs in Childhood Acute Lymphoblastic Leukemia: Mechanisms and Clinical Implications

microRNAs (miRNAs), tiny, non-coding RNA molecules, fine-tune the expression of target genes through interacting with mRNAs. These miRNAs are involved in a wide range of biological processes, encompassing cell division, death, blood cell production, and tumor development. When these miRNAs become dysfunctional, they can promote the invasion and spread of cancer cells in various human malignancies, including leukemia. Acute lymphoblastic leukemia (ALL), the preeminent malignancy affecting children, is a blood cancer marked by the uncontrollable growth of immature lymphoid cells that displace healthy blood precursors in the bone marrow. Despite a decline in ALL mortality rates over the past two decades, a significant proportion of deaths still results from a lack of effective diagnostic and prognostic markers that can guide treatment decisions and overcome drug resistance. The analysis of miRNA expression patterns in ALL could lead to more precise disease classification, earlier diagnosis, and better prognostic outcomes in the near future. The connection between miRNA dysfunction and the biology of ALL suggests that these molecules could represent promising therapeutic targets. Therefore, this review delves into the regulatory mechanisms of miRNAs in pediatric ALL, exploring how miRNA-based diagnostic, prognostic, and therapeutic strategies offer unique advantages and hold promise for clinical applications.

Extracellular vesicles in hematological malignancies: EV-dence for reshaping the tumoral microenvironment

Following their discovery at the end of the 20th century, extracellular vesicles (EVs) ranging from 50-1,000 nm have proven to be paramount in the progression of many cancers, including hematological malignancies. EVs are a heterogeneous group of cell-derived membranous structures that include small EVs (commonly called exosomes) and large EVs (microparticles). They have been demonstrated to participate in multiple physiological and pathological processes by allowing exchange of biological material (including among others proteins, DNA and RNA) between cells. They are therefore a crucial way of intercellular communication. In this context, malignant cells can release these extracellular vesicles that can influence their microenvironment, induce the formation of a tumorigenic niche, and prepare and establish distant niches facilitating metastasis by significantly impacting the phenotypes of surrounding cells and turning them toward supportive roles. In addition, EVs are also able to manipulate the immune response and to establish an immunosuppressive microenvironment. This in turn allows for ideal conditions for heightened chemoresistance and increased disease burden. Here, we review the latest findings and reports studying the effects and therapeutic potential of extracellular vesicles in various hematological malignancies. The study of extracellular vesicles remains in its infancy; however, rapid advances in the analysis of these vesicles in the context of disease allow us to envision prospects to improve the detection and treatment of hematological malignancies.

In vitro simulation of the acute lymphoblastic leukemia niche: a critical view on the optimal approximation for drug testing

Acute lymphoblastic leukemia with the worst prognosis is related to minimal residual disease. Minimal residual disease not only depends on the individual peculiarities of leukemic clones but also reflects the protective role of the acute lymphoblastic leukemia microenvironment. In this review, we discuss in detail cell-to-cell interactions in the 2 leukemic niches, more explored bone marrow and less studied extramedullary adipose tissue. A special emphasis is given to multiple ways of interactions of acute lymphoblastic leukemia cells with the bone marrow or extramedullary adipose tissue microenvironment, indicating observed differences in B- and T-cell-derived acute lymphoblastic leukemia behavior. This analysis argued for the usage of coculture systems for drug testing. Starting with a review of available sources and characteristics of acute lymphoblastic leukemia cells, mesenchymal stromal cells, endothelial cells, and adipocytes, we have then made an update of the available 2-dimensional and 3-dimensional systems, which bring together cellular elements, components of the extracellular matrix, or its imitation. We discussed the most complex available 3-dimensional systems like "leukemia-on-a-chip," which include either a prefabricated microfluidics platform or, alternatively, the microarchitecture, designed by using the 3-dimensional bioprinting technologies. From our analysis, it follows that for preclinical antileukemic drug testing, in most cases, intermediately complex in vitro cell systems are optimal, such as a "2.5-dimensional" coculture of acute lymphoblastic leukemia cells with niche cells (mesenchymal stromal cells, endothelial cells) plus matrix components or scaffold-free mesenchymal stromal cell organoids, populated by acute lymphoblastic leukemia cells. Due to emerging evidence for the correlation of obesity and poor prognosis, a coculture of adipocytes with acute lymphoblastic leukemia cells as a drug testing system is gaining shape.

MiRNAs in Hematopoiesis and Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common kind of pediatric cancer. Although the cure rates in ALL have significantly increased in developed countries, still 15–20% of patients relapse, with even higher rates in developing countries. The role of non-coding RNA genes as microRNAs (miRNAs) has gained interest from researchers in regard to improving our knowledge of the molecular mechanisms underlying ALL development, as well as identifying biomarkers with clinical relevance. Despite the wide heterogeneity reveled in miRNA studies in ALL, consistent findings give us confidence that miRNAs could be useful to discriminate between leukemia linages, immunophenotypes, molecular groups, high-risk-for-relapse groups, and poor/good responders to chemotherapy. For instance, miR-125b has been associated with prognosis and chemoresistance in ALL, miR-21 has an oncogenic role in lymphoid malignancies, and the miR-181 family can act either as a oncomiR or tumor suppressor in several hematological malignancies. However, few of these studies have explored the molecular interplay between miRNAs and their targeted genes. This review aims to state the different ways in which miRNAs could be involved in ALL and their clinical implications.

Tumour‑derived exosomes and their emerging roles in leukaemia (Review)

Exosomes are small vesicles with a diameter of ~40-100 nm that are secreted by the majority of endogenous cells under normal and pathological conditions. They contain abundant proteins, lipids, microRNAs, and biomolecules such as signal transduction molecules, adhesion factors and cytoskeletal proteins, and play an important role in exchanging materials and transmitting information between cells. Recent studies have shown that exosomes are involved in the pathophysiology of leukaemia by affecting the bone marrow microenvironment, apoptosis, tumour angiogenesis, immune escape and chemotherapy resistance. Furthermore, exosomes are potential biomarkers and drug carriers for leukaemia, impacting the diagnosis and treatment of leukaemia. The present study describes the biogenesis and general characteristics of exosomes, and then highlight the emerging roles of exosomes in different types of leukaemia. Finally, the value of clinical application of exosomes as biomarkers and drug carriers is discussed with the aim to provide novel strategies for the treatment of leukaemia.

Circulating miRNA Expression Profiles and Machine Learning Models in Association with Response to Irinotecan-Based Treatment in Metastatic Colorectal Cancer

Colorectal cancer represents a leading cause of cancer-related morbidity and mortality. Despite improvements, chemotherapy remains the backbone of colorectal cancer treatment. The aim of this study is to investigate the variation of circulating microRNA expression profiles and the response to irinotecan-based treatment in metastatic colorectal cancer and to identify relevant target genes and molecular functions. Serum samples from 95 metastatic colorectal cancer patients were analyzed. The microRNA expression was tested with a NucleoSpin miRNA kit (Machnery-Nagel, Germany), and a machine learning approach was subsequently applied for microRNA profiling. The top 10 upregulated microRNAs in the non-responders group were hsa-miR-181b-5p, hsa-miR-10b-5p, hsa-let-7f-5p, hsa-miR-181a-5p, hsa-miR-181d-5p, hsa-miR-301a-3p, hsa-miR-92a-3p, hsa-miR-155-5p, hsa-miR-30c-5p, and hsa-let-7i-5p. Similarly, the top 10 downregulated microRNAs were hsa-let-7d-5p, hsa-let-7c-5p, hsa-miR-215-5p, hsa-miR-143-3p, hsa-let-7a-5p, hsa-miR-10a-5p, hsa-miR-142-5p, hsa-miR-148a-3p, hsa-miR-122-5p, and hsa-miR-17-5p. The upregulation of microRNAs in the miR-181 family and the downregulation of those in the let-7 family appear to be mostly involved with non-responsiveness to irinotecan-based treatment.

Extracellular Vesicles in Haematological Disorders: A Friend or a Foe?

Extracellular vesicles (EVs) have emerged as important mediators of homeostasis, immune modulation and intercellular communication. They are released by every cell of the human body and accordingly detected in a variety of body fluids. Interestingly, their expression can be upregulated under various conditions, such as stress, hypoxia, irradiation, inflammation, etc. Their cargo, which is variable and may include lipids, proteins, RNAs and DNA, reflects that of the parental cell, which offers a significant diagnostic potential to EVs. In line with this, an increasing number of studies have reported the important contribution of cancer-derived EVs in altering the tumour microenvironment and allowing for cancer progression and metastasis. As such, cancer-derived EVs may be used to monitor the development and progression of disease and to evaluate the potential response to treatment, which has generated much excitement in the field of oncology and particularly in haemato-oncology. Finally, EVs are able to transfer their cargo to target cells, modifying the properties of the recipient cell, which offers great therapeutic potential for EVs (either by specific drug delivery or by delivery of siRNAs and other inhibitory proteins). In this manuscript, we review the potential diagnostic use and therapeutic options of EVs in the context of haematological malignancies.

MiRNA-181b-5p Modulates Cell Proliferation, Cell Cycle and Apoptosis by Targeting SSX2IP in Acute Lymphoblastic Leukemia

Objective:

Accumulating evidence indicates that miRNAs can negatively influence the expression of their downstream genes, thereby affecting the development of human cancers. The pathogenesis of acute lymphoblastic leukemia (ALL) is complex and more biomarkers and functional molecules need to be found. We attempted to reveal the specific mechanisms and functions of miRNA-181b-5p in ALL and investigated the effects of the miRNA-181b-5p/SSX2IP axis on ALL.

Materials and Methods:

Bioinformatics analyses were initially performed to screen out differentially expressed miRNAs in ALL and determine the research subject. qRT-PCR and western blotting were applied to evaluate the expression levels of target genes. Cell function experiments and mouse experiments were conducted to analyze the roles of the target genes in ALL.

Results:

miRNA-181b-5p was highly and differentially expressed in ALL and may target SSX2IP. The upregulation of miRNA-181b-5p and downregulation of SSX2IP were observed in ALL cells. miRNA-181b-5p could control multiple pathological processes of ALL, including cell proliferation, the cell cycle, and apoptosis, and miRNA-181b-5p could also facilitate tumor growth in vivo.

Conclusion:

miRNA-181b-5p promoted the malignant progression of ALL by downregulating SSX2IP. The miRNA-181b-5p/SSX2IP axis may be a promising target for intervention against the malignant behaviors of ALL.