Extracellular Vesicles in Acute Leukemia: A Mesmerizing Journey With a Focus on Transferred microRNAs

Comparative proteomics uncovers vital molecular players of central nervous system leukemia among Mexican pediatric patients

Acute lymphoblastic leukemia (ALL) is the most common pediatric hematologic malignancy. The leukemic cells start in the bone marrow and spread to other vital organs and tissues, including the central nervous system (CNS). Hispanic males are the community with the highest incidence of ALL. Unfortunately, there is limited information on the molecular signatures of leukemic cell infiltration into the CNS, which marks the progression from ALL to central nervous system leukemia (CNSL). To address this knowledge gap, we performed a label-free shotgun proteomics between the cerebrospinal fluid (CSF) from patients with ALL compared to those with confirmed CNSL. We were able to identify 619 proteins, including 340 proteins that had not been reported prevously in the CSF of subjects with CNSL. The major features associated with CNSL included the over-accumulation of cell-adhesion proteins such as L-selectin and several cadherin proteins, along with the modulation of enzymes associated with protein glycosylation, which may provide the appropriate conditions for leukemic cell infiltration into the CNS. The over-accumulation of proteins associated with ROS scavenging processes reveals hypoxic and redox homeostasis microenvironment conditions that favors ALL progression to CNSL. The further characterization of key differential proteins will be essential for establishing reliable molecular markers for CSNL. BIOLOGICAL SIGNIFICANCE: Central nervous system leukemia (CNSL) is a catastrophic progression of ALL defined by leukemic cells reaching the CNS. Limited comparative proteomics studies have been conducted previously between patients with ALL versus CNSL. While these studies were important pioneering steps, they were hindered by difficulties in obtaining the proper amount of protein samples related to CSF. They were based on minimal study subjects, and their proteomics pipelines did not include the depletion of high-abundance proteins. Defining the manners in which the CNSL proteome is perturbed compared to the ALL condition is paramount to understanding the molecular foundations of CNSL and identifying and characterizing protein markers for proper diagnosis. Improving the sensitivity and reliability of diagnosis using molecular markers would help clinicians to maximize patient outcomes and quality of life by implementing aggressive CNSL treatments as soon as possible in cases where infiltration has occurred, while avoiding exposure to toxic chemotherapies in patients where they are not yet necessary.

Extracellular vesicles in acute myeloid leukemia: The role in disease pathogenesis, potential biomarker, and application in clinical settings

Acute myeloid leukemia (AML), the most prevalent type of blood cancer, is initiated in the bone marrow and eventually migrates into the blood. It accounts for a 5-year overall survival rate of 29.8 %. AML results from the formation of immature white blood cells, also called AML blasts, from hematopoietic stem cells which eventually give rise to abnormal white blood cells, termed AML cells. The interaction of AML cells with their microenvironment appears to be significantly important in the pathogenesis of AML. A growing body of evidence identifies extracellular vesicles (EVs) to be a key component in intercellular communication via the transfer of biomolecules, such as DNA, RNAs, proteins, non-coding RNAs, lipids, metabolites etc. Although the role of EVs in various solid tumors is well-established, EVs' contribution to the pathogenesis of blood cancer, such as AML remains ill-defined. The present review highlights how EVs promote the progression of AML by influencing leukemogenesis, survival, angiogenesis, chemotherapeutic resistance, and immune evasion. A significant number of EVs are found in the biofluids of AML patients which are shown to carry signature cargo molecules, thereby rendering the EVs as predictive biomarkers for AML pathogenesis. EV-based clinical trials are mentioned in the later part of the review. Finally, EV-based therapeutics and their limitations are also briefly discussed in the context of AML.

Parallel single-cell metabolic analysis and extracellular vesicle profiling reveal vulnerabilities with prognostic significance in acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive disease with a high relapse rate. In this study, we map the metabolic profile of CD34+(CD38low/-) AML cells and the extracellular vesicle signatures in circulation from AML patients at diagnosis. CD34+ AML cells display high antioxidant glutathione levels and enhanced mitochondrial functionality, both associated with poor clinical outcomes. Although CD34+ AML cells are highly dependent on glucose oxidation and glycolysis for energy, those from intermediate- and adverse-risk patients reveal increased mitochondrial dependence. Extracellular vesicles from AML are mainly enriched in stem cell markers and express antioxidant GPX3, with their profiles showing potential prognostic value. Extracellular vesicles enhance mitochondrial functionality and dependence on CD34+ AML cells via the glutathione/GPX4 axis. Notably, extracellular vesicles from adverse-risk patients enhance leukemia cell engraftment in vivo. Here, we show a potential noninvasive approach based on liquid 'cell-extracellular vesicle' biopsy toward a redefined metabolic stratification in AML.

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.

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.

The impact of exosomes derived from B-cell acute lymphoblastic leukemia as a growth factor on bone marrow mesenchymal stromal cells

Background The incidence of various types of cancers, including leukemia, is on the rise and many challenges in both drug resistance and complications related to chemotherapy appeared. Recently, the development and application of extracellular vesicles (EV) such as exosomes in the management of cancers, especially leukemia, holds great significance. In this article, we extracted exosomes from NALM6 cells and assessed their regulatory effects on proliferation and apoptosis in mesenchymal stem cells (MSCs). Method and result We first verified the exosomes using various techniques, including flow cytometry, transient electron microscopy, dynamic light scattering (DLS), and BCA protein assay. Then MTT analysis and flowcytometry (apoptosis and cell cycle assay) besides gene expressions were employed to determine the state of MSC proliferations. The results indicated that exosome-specific pan markers like CD9, CD63, and CD81 were present. Through DLS, we found out that the mean size of the exosomes was 89.68 nm. The protein content was determined to be 956.292 µg/ml. Analysis of MTT, flow cytometry (cell cycle and apoptosis assay), and RT-qPCR showed that in the dose of 50 µg/ml the proliferation of MSCs was increased significantly (p-value < 0.05). Conclusion All these data showed that exosomes use several signaling pathways to increase the MSCs' proliferation and drug resistance, ultimately leading to high mortalities and morbidities of acute lymphoblastic leukemia.

Cell Type-Specific Extracellular Vesicles and Their Impact on Health and Disease

Extracellular vesicles (EVs), a diverse group of cell-derived exocytosed particles, are pivotal in mediating intercellular communication due to their ability to selectively transfer biomolecules to specific cell types. EVs, composed of proteins, nucleic acids, and lipids, are taken up by cells to affect a variety of signaling cascades. Research in the field has primarily focused on stem cell-derived EVs, with a particular focus on mesenchymal stem cells, for their potential therapeutic benefits. Recently, tissue-specific EVs or cell type-specific extracellular vesicles (CTS-EVs), have garnered attention for their unique biogenesis and molecular composition because they enable highly targeted cell-specific communication. Various studies have outlined the roles that CTS-EVs play in the signaling for physiological function and the maintenance of homeostasis, including immune modulation, tissue regeneration, and organ development. These properties are also exploited for disease propagation, such as in cancer, neurological disorders, infectious diseases, autoimmune conditions, and more. The insights gained from analyzing CTS-EVs in different biological roles not only enhance our understanding of intercellular signaling and disease pathogenesis but also open new avenues for innovative diagnostic biomarkers and therapeutic targets for a wide spectrum of medical conditions. This review comprehensively outlines the current understanding of CTS-EV origins, function within normal physiology, and implications in diseased states.

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.

Circular RNAs: pivotal role in the leukemogenesis and novel indicators for the diagnosis and prognosis of acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive hematological malignancy and affected patients have poor overall survival (OS) rates. Circular RNAs (circRNAs) are a novel class of non-coding RNAs (ncRNAs) with a unique loop structure. In recent years, with the development of high-throughput RNA sequencing, many circRNAs have been identified exhibiting either up-regulation or down-regulation in AML patients compared with healthy controls. Recent studies have reported that circRNAs regulate leukemia cell proliferation, stemness, and apoptosis, both positively and negatively. Additionally, circRNAs could be promising biomarkers and therapeutic targets in AML. In this study, we present a comprehensive review of the regulatory roles and potentials of a number of dysregulated circRNAs in AML.

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.