Silencing of Exosomal miR-181a Reverses Pediatric Acute Lymphocytic Leukemia Cell Proliferation

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.

Leukemia cancer cells and immune cells derived-exosomes: Possible roles in leukemia progression and therapy

Exosomes have a significant impact on tumor survival, proliferation, metastasis, and recurrence. They also open up new therapeutic options and aid in the pathological identification and diagnosis of cancers. Exosomes have been shown in numerous studies to be essential for facilitating cell-to-cell communication. In B-cell hematological malignancies, the proteins and RNAs that are encased by circulating exosomes are thought to represent prospective sources for therapeutic drugs as well as biomarkers for diagnosis and prognosis. Additionally, exosomes can offer a "snapshot" of the tumor and the metastatic environment at any given point in time. In this review study, we concluded that leukemia-derived exosomes could be utilized as prognostic, diagnostic, and therapeutic biomarkers for individuals suffering from leukemia. Moreover, clinical studies have demonstrated that immune cells like dendritic cells create exosomes, which have the ability to activate the immune system against leukemia.

State of the art in pediatric nanomedicines

In recent years, the continuous development of innovative nanopharmaceuticals is expanding their biomedical and clinical applications. Nanomedicines are being revolutionized to circumvent the limitations of unbound therapeutic agents as well as overcome barriers posed by biological interfaces at the cellular, organ, system, and microenvironment levels. In many ways, the use of nanoconfigured delivery systems has eased challenges associated with patient differences, and in our opinion, this forms the foundation for their potential usefulness in developing innovative medicines and diagnostics for special patient populations. Here, we present a comprehensive review of nanomedicines specifically designed and evaluated for disease management in the pediatric population. Typically, the pediatric population has distinguishing needs relative to those of adults majorly because of their constantly growing bodies and age-related physiological changes, which often need specialized drug formulation interventions to provide desirable therapeutic effects and outcomes. Besides, child-centric drug carriers have unique delivery routes, dosing flexibility, organoleptic properties (e.g., taste, flavor), and caregiver requirements that are often not met by traditional formulations and can impact adherence to therapy. Engineering pediatric medicines as nanoconfigured structures can potentially resolve these limitations stemming from traditional drug carriers because of their unique capabilities. Consequently, researchers from different specialties relentlessly and creatively investigate the usefulness of nanomedicines for pediatric disease management as extensively captured in this compilation. Some examples of nanomedicines covered include nanoparticles, liposomes, and nanomicelles for cancer; solid lipid and lipid-based nanostructured carriers for hypertension; self-nanoemulsifying lipid-based systems and niosomes for infections; and nanocapsules for asthma pharmacotherapy.

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.

Ultrasound-Responsive Micelle-Encapsulated Mesenchymal Stem Cell-Derived EVs for the Treatment of Lower Limb Microcirculation Disease

Lower limb microcirculatory ischemic disease is a vascular disorder primarily characterized by limb pain, gangrene, and potential amputation. It can be caused by various factors, such as hyperglycemia, atherosclerosis, and infection. Due to the extremely narrow luminal diameter in lower limb microcirculatory ischemic lesions, both surgical and medical interventions face challenges in achieving satisfactory therapeutic outcomes within the microvessels. Extracellular vesicles derived from mesenchymal stem cells (MSCs-EVs) exhibit promising potential in the treatment of microcirculation ischemic lesions due to their small size and ability to promote angiogenesis. After undergoing substantial losses during the process of EVs transportation, only a minimal fraction of EVs can effectively reach the site of microcirculatory lesions, thereby compromising the therapeutic efficacy for microcirculatory disorders. Herein, an ultrasound-responsive system utilizing 2-(dimethylamino)ethyl methacrylate-b-2-tetrahydropyranyl methacrylate (DMAEMA-b-THPMA) micelles to encapsulate MSCs-EVs has been successfully constructed, with the aim of achieving localized and targeted release of EVs at the site of microcirculatory lesions. The reversible addition-fragmentation chain transfer (RAFT) polymerization method facilitates the successful synthesis of diblock copolymers comprising monomer 2-(dimethylamino)ethyl methacrylate (DMAEMA) and monomer 2-tetrahydropyranyl methacrylate (THPMA). The DMAEMA-b-THPMA micelles exhibit a nanoscale structure, reliable biocompatibility, ultrasound responsiveness, and conspicuous protection of EVs. Furthermore, the implementation of low-energy-density ultrasound can enhance angiogenesis by upregulating the levels of the vascular endothelial growth factor (VEGF). In in vivo experiments, the ultrasound-responsive system of the DMAEMA-b-THPMA micelles and MSCs-EVs synergistically enhances therapeutic efficacy by promoting angiogenesis, improving vascular permeability, and optimizing vascular. In conclusion, this work demonstrates bioapplication of an ultrasound-responsive micellar nanosystem loaded with EVs for the treatment of lower limb microcirculatory ischemic disorders.

Application of cell-derived exosomes in the hematological malignancies therapy

Exosomes are small membrane vesicles of endocytic origin that are produced by both tumor and normal cells and can be found in physiological fluids like plasma and cell culture supernatants. They include cytokines, growth factors, proteins, lipids, RNAs, and metabolites and are important intercellular communication controllers in several disorders. According to a vast amount of research, exosomes could support or inhibit tumor start and diffusion in a variety of solid and hematological malignancies by paracrine signaling. Exosomes are crucial therapeutic agents for a variety of illnesses, such as cancer and autoimmune diseases. This review discusses the most current and encouraging findings from in vitro and experimental in vivo research, as well as the scant number of ongoing clinical trials, with a focus on the impact of exosomes in the treatment of malignancies. Exosomes have great promise as carriers of medications, antagonists, genes, and other therapeutic materials that can be incorporated into their core in a variety of ways. Exosomes can also alter the metabolism of cancer cells, alter the activity of immunologic effectors, and alter non-coding RNAs, all of which can alter the tumor microenvironment and turn it from a pro-tumor to an anti-tumor milieu. This subject is covered in the current review, which also looks at how exosomes contribute to the onset and progression of hematological malignancies, as well as their importance in diagnosing and treating these conditions.

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.

Exosomes and cancer immunotherapy: A review of recent cancer research

As phospholipid extracellular vesicles (EVs) secreted by various cells, exosomes contain non-coding RNA (ncRNA), mRNA, DNA fragments, lipids, and proteins, which are essential for intercellular communication. Several types of cells can secrete exosomes that contribute to cancer initiation and progression. Cancer cells and the immune microenvironment interact and restrict each other. Tumor-derived exosomes (TDEs) have become essential players in this balance because they carry information from the original cancer cells and express complexes of MHC class I/II epitopes and costimulatory molecules. In the present study, we aimed to identify potential targets for exosome therapy by examining the specific expression and mechanism of exosomes derived from cancer cells. We introduced TDEs and explored their role in different tumor immune microenvironment (TIME), with a particular emphasis on gastrointestinal cancers, before briefly describing the therapeutic strategies of exosomes in cancer immune-related therapy.

Extracellular Vesicles Derived from Human Bone Marrow Stem Cells Inhibit Acute Lymphoblastic Leukemia Cell Growth by Inhibiting MAPK Pathway via the miR-29b-3p/GDF15 Axis

INTRODUCTION

Acute lymphoblastic leukemia (ALL) is a common hematologic neoplastic disease. This study discussed the effect of extracellular vesicles (EVs) released from bone marrow mesenchymal stem cells (BMSCs) on ALL cells and the mechanism.

METHODS

BMSCs-EVs were isolated by differential centrifugation and identified. The effect of BMSCs-EVs on ALL cell proliferation and apoptosis was evaluated. The expression of miR-29b-3p in ALL cells and EVs was detected. The uptake of EVs by ALL cells was observed. The effect of miR-29b-3p on ALL cell proliferation and apoptosis was assessed after silencing miR-29b-3p. The targeting relation of miR-29b-3p and GDF15 was analyzed by bioinformatics website and dual-luciferase assay. The role of GDF15 in proliferation and apoptosis of ALL cells was further confirmed, and Western blot assay was performed to measure MAPK pathway-related protein levels.

RESULTS

BMSC-derived EVs inhibited proliferation and promoted apoptosis of ALL cells, as shown by the up-regulation of caspase-3 and Bax expressions and down-regulation of Bcl-2 expression. EVs carried miR-29b-3p into ALL cells, upregulated miR-29b-3p expression in ALL cells, and inhibited GDF15 expression. Silencing of miR-29b-3p or overexpression of GDF15 partially reversed the effect of EVs. EVs inhibited the MAPK pathway through the miR-29b-3p/GDF15 axis.

CONCLUSION

BMSCs-EVs carried miR-29b-3p into ALL cells, upregulated miR-29b-3p, and inhibited GDF15 to suppress the MAPK pathway and further inhibit proliferation and promote apoptosis of ALL cells.

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.

MicroRNAs and the Diagnosis of Childhood Acute Lymphoblastic Leukemia: Systematic Review, Meta-Analysis and Re-Analysis with Novel Small RNA-Seq Tools

Simple Summary

MicroRNAs (miRNAs) have been under the spotlight for the last three decades. These non-coding RNAs seem to be dynamic regulators of mRNA stability and translation, in addition to interfering with transcription. Circulating miRNAs play a critical role in cell-to-cell interplay; therefore, they can serve as disease biomarkers. Meta-analysis of published data revealed that the CC genotype of rs4938723 in pri-miR-34b/c and the TT genotype of rs543412 in miR-100 confer protection against acute lymphoblastic leukemia (ALL) in children. Reanalysis of small RNA-seq data with novel tools identified significantly overexpressed members of the miR-128, miR-181, miR-130 and miR-17 families and significantly lower expression of miR-30, miR-24-2 and miR143~145 clusters, miR-574 and miR-618 in pediatric T-ALL cases compared with controls. Inconsistencies in methodology and study designs in most published material preclude reproducibility, and further cohort studies need to be conducted in order to empower novel tools, such as ALLSorts and RNAseqCNV.

Abstract

MicroRNAs (miRNAs) have been implicated in childhood acute lymphoblastic leukemia (ALL) pathogenesis. We performed a systematic review and meta-analysis of miRNA single-nucleotide polymorphisms (SNPs) in childhood ALL compared with healthy children, which revealed (i) that the CC genotype of rs4938723 in pri-miR-34b/c and the TT genotype of rs543412 in miR-100 confer protection against ALL occurrence in children; (ii) no significant association between rs2910164 genotypes in miR-146a and childhood ALL; and (iii) SNPs in DROSHA, miR-449b, miR-938, miR-3117 and miR-3689d-2 genes seem to be associated with susceptibility to B-ALL in childhood. A review of published literature on differential expression of miRNAs in children with ALL compared with controls revealed a significant upregulation of the miR-128 family, miR-130b, miR-155, miR-181 family, miR-210, miR-222, miR-363 and miR-708, along with significant downregulation of miR-143 and miR-148a, seem to have a definite role in childhood ALL development. MicroRNA signatures among childhood ALL subtypes, along with differential miRNA expression patterns between B-ALL and T-ALL cases, were scrutinized. With respect to T-ALL pediatric cases, we reanalyzed RNA-seq datasets with a robust and sensitive pipeline and confirmed the significant differential expression of hsa-miR-16-5p, hsa-miR-19b-3p, hsa-miR-92a-2-5p, hsa-miR-128-3p (ranked first), hsa-miR-130b-3p and -5p, hsa-miR-181a-5p, -2-3p and -3p, hsa-miR-181b-5p and -3p, hsa-miR-145-5p and hsa-miR-574-3p, as described in the literature, along with novel identified miRNAs.

The Landscape of Exosome-Derived Non-Coding RNA in Leukemia

Leukemia is a group of life-threatening hematological malignancies which is currently incurable and often accompanied by drug resistance or disease relapse. Understanding the pathogenesis of leukemia and finding specific therapeutic targets and biomarkers is of great importance to improve the clinical efficacy of leukemia. Exosome-derived ncRNAs have been demonstrated as critical components of intercellular communication and function as key facilitators in the leukemia biological process. This review outlines the current investigations of exosomal ncRNAs (including miRNA, circRNA, and lncRNA) as important mediators of leukemia and potential therapeutic targets and biomarkers for leukemia treatment. Moreover, we generally analyze the prospects and challenges for exosomal ncRNAs from the aspects of research and clinical application.

Plasma-Enabled Smart Nanoexosome Platform as Emerging Immunopathogenesis for Clinical Viral Infection

Smart nanoexosomes are nanosized structures enclosed in lipid bilayers that are structurally similar to the viruses released by a variety of cells, including the cells lining the respiratory system. Of particular importance, the interaction between smart nanoexosomes and viruses can be used to develop antiviral drugs and vaccines. It is possible that nanoexosomes will be utilized and antibodies will be acquired more successfully for the transmission of an immune response if reconvalescent plasma (CP) is used instead of reconvalescent plasma exosomes (CPExo) in this concept. Convalescent plasma contains billions of smart nanoexosomes capable of transporting a variety of molecules, including proteins, lipids, RNA and DNA among other viral infections. Smart nanoexosomes are released from virus-infected cells and play an important role in mediating communication between infected and uninfected cells. Infections use the formation, production and release of smart nanoexosomes to enhance the infection, transmission and intercellular diffusion of viruses. Cell-free smart nanoexosomes produced by mesenchymal stem cells (MSCs) could also be used as cell-free therapies in certain cases. Smart nanoexosomes produced by mesenchymal stem cells can also promote mitochondrial function and heal lung injury. They can reduce cytokine storms and restore the suppression of host antiviral defenses weakened by viral infections. This study examines the benefits of smart nanoexosomes and their roles in viral transmission, infection, treatment, drug delivery and clinical applications. We also explore some potential future applications for smart nanoexosomes in the treatment of viral infections.

Exosome-Mediated Therapeutic Strategies for Management of Solid and Hematological Malignancies

Exosomes are small membrane vesicles of endocytic origin containing cytokines, RNAs, growth factors, proteins, lipids, and metabolites. They have been identified as fundamental intercellular communication controllers in several diseases and an enormous volume of data confirmed that exosomes could either sustain or inhibit tumor onset and diffusion in diverse solid and hematological malignancies by paracrine signaling. Thus, exosomes might constitute a promising cell-free tumor treatment alternative. This review focuses on the effects of exosomes in the treatment of tumors, by discussing the most recent and promising data from in vitro and experimental in vivo studies and the few existing clinical trials. Exosomes are extremely promising as transporters of drugs, antagomir, genes, and other therapeutic substances that can be integrated into their core via different procedures. Moreover, exosomes can augment or inhibit non-coding RNAs, change the metabolism of cancer cells, and modify the function of immunologic effectors thus modifying the tumor microenvironment transforming it from pro-tumor to antitumor milieu. Here, we report the development of currently realized exosome modifiers that offer indications for the forthcoming elaboration of other more effective methods capable of enhancing the activity of the exosomes.

Small Non-Coding RNAs in Leukemia

In 2020, more than 60,500 people were diagnosed with leukemia in the USA, and more than 23,000 died. The incidence of leukemia is still rising, and drug resistance development is a serious concern for patients' wellbeing and survival. In the past two decades, small non-coding RNAs have been studied to evaluate their functions and possible role in cancer pathogenesis. Small non-coding RNAs are short RNA molecules involved in several cellular processes by regulating the expression of genes. An increasing body of evidence collected by many independent studies shows that the expression of these molecules is tissue specific, and that their dysregulation alters the expression of genes involved in tumor development, progression and drug response. Indeed, small non-coding RNAs play a pivotal role in the onset, staging, relapse and drug response of hematological malignancies and cancers in general. These findings strongly suggest that small non-coding RNAs could function as biomarkers and possible targets for therapy. Thus, in this review, we summarize the regulatory mechanisms of small non-coding RNA expression in different types of leukemia and assess their potential clinical implications.

miRNA-seq and clinical evaluation in multiple myeloma: miR-181a overexpression predicts short-term disease progression and poor post-treatment outcome

BACKGROUND

Despite significant advances in multiple myeloma (MM) therapy, disease relapse and treatment resistance remain major obstacles in clinical management. Herein, we have studied the clinical utility of miRNAs in improving patients' risk-stratification and prognosis.

METHODS

miRNA-seq was performed in CD138+ plasma cells of MM, smoldering multiple myeloma (sMM) and monoclonal gammopathy of undetermined significance (MGUS) patients. The screening MM cohort consisted of 138 patients. miRNA levels of CD138+ plasma cells were quantified by RT-qPCR following 3'-end RNA polyadenylation. Disease progression and patients' death were used as clinical end-point events. Internal validation was conducted by bootstrap analysis. Clinical net benefit on disease prognosis was assessed by decision curve analysis. Kruykov et al. 2016 served as validation cohort (n = 151).

RESULTS

miRNA-seq highlighted miR-181a to be upregulated in MM vs. sMM/MGUS, and R-ISS III vs. I patients. Screening and validation cohorts confirmed the significantly higher risk for short-term progression and worse survival of the patients overexpressing miR-181a. Multivariate models integrating miR-181a with disease established markers led to superior risk-stratification and clinical benefit for MM prognosis.

CONCLUSIONS

CD138+ overexpression of miR-181a was strongly correlated with inferior disease outcome and contributed to superior prediction of MM patients early progression, supporting personalised prognosis and treatment decisions.

Hyperleukocytic Acute Leukemia Circulating Exosomes Regulate HSCs and BM-MSCs

Hyperleukocytic acute leukemia (HLAL) circulating exosomes are delivered to hematopoietic stem cells (HSCs) and bone marrow mesenchymal stem cells (BM-MSCs), thereby inhibiting the normal hematopoietic process. In this paper, we have evaluated and explored the effects of miR-125b, which is carried by HLAL-derived exosomes, on the hematopoietic function of HSCs and BM-MSCs. For this purpose, we have isolated exosomes from the peripheral blood of HLAL patients and healthy volunteers. Then, we measured the level of miR-125b in exosomes cocultured exosomes with HSCs and BM-MSCs. Moreover, we have used miR-125b inhibitors/mimic for intervention and then measured miR-125b expression and colony forming unit (CFU). Apart from it, HSC and BM-MSC hematopoietic-related factors α-globulin, γ-globulin, CSF2, CRTX4 and CXCL12, SCF, IGF1, and DKK1 expression were measured. Evaluation of the miR-125b and BAK1 targeting relationship, level of miR-125b, and expression of hematopoietic-related genes was performed after patients are treated with miR-125b mimic and si-BAK1. We have observed that miR-125b was upregulated in HLAL-derived exosomes. After HLAL-exosome acts on HSCs, the level of miR-125b is upregulated, reducing CFU and affecting the expression of α-globulin, γ-globulin, CSF2, and CRCX4. For BM-MSCs, after the action of HLAL-exo, the level of miR-125b is upregulated and affected the expression of CXCL12, SCF, IGF1, and DKK1. Exosomes derived from HLAL carry miR-125b to target and regulate BAK1. Further study confirmed that miR-125b and BAK1mimic reduced the expression of miR-125b and reversed the effect of miR-125b mimic on hematopoietic-related genes. These results demonstrated that HLAL-derived exosomes carrying miR-125b inhibit the hematopoietic differentiation of HSC and hematopoietic support function of BM-MSC through BAK1.

The Importance of Exosomal PD-L1 in Cancer Progression and Its Potential as a Therapeutic Target

Binding of programmed cell death ligand 1 (PD-L1) to its receptor programmed cell death protein 1 (PD-1) can lead to the inactivation of cytotoxic T lymphocytes, which is one of the mechanisms for immune escape of tumors. Immunotherapy based on this mechanism has been applied in clinic with some remaining issues such as drug resistance. Exosomal PD-L1 derived from tumor cells is considered to play a key role in mediating drug resistance. Here, the effects of various tumor-derived exosomes and tumor-derived exosomal PD-L1 on tumor progression are summarized and discussed. Researchers have found that high expression of exosomal PD-L1 can inhibit T cell activation in in vitro experiments, but the function of exosomal PD-L1 in vivo remains controversial. In addition, the circulating exosomal PD-L1 has high potential to act as an indicator to evaluate the clinical effect. Moreover, therapeutic strategy targeting exosomal PD-L1 is discussed, such as inhibiting the biogenesis or secretion of exosomes. Besides, some specific methods based on the strategy of inhibiting exosomes are concluded. Further study of exosomal PD-L1 may provide an effective and safe approach for tumor treatment, and targeting exosomal PD-L1 by inhibiting exosomes may be a potential method for tumor treatment.

Towards Unravelling the Role of ERα-Targeting miRNAs in the Exosome-Mediated Transferring of the Hormone Resistance

Hormone therapy is one of the most effective breast cancer treatments, however, its application is limited by the progression of hormonal resistance, both primary or acquired. The development of hormonal resistance is caused either by an irreversible block of hormonal signalling (suppression of the activity or synthesis of hormone receptors), or by activation of oestrogen-independent signalling pathways. Recently the effect of exosome-mediated intercellular transfer of hormonal resistance was revealed, however, the molecular mechanism of this effect is still unknown. Here, the role of exosomal miRNAs (microRNAs) in the transferring of hormonal resistance in breast cancer cells has been studied. The methods used in the work include extraction, purification and RNAseq of miRNAs, transfection of miRNA mimetics, immunoblotting, reporter analysis and the MTT test. Using MCF7 breast cancer cells and MCF7/T tamoxifen-resistant sub-line, we have found that some miRNAs, suppressors of oestrogen receptor signalling, are overexpressed in the exosomes of the resistant breast cancer cells. The multiple (but not single) transfection of one of the identified miRNA, miR-181a-2, into oestrogen-dependent MCF7 cells induced the irreversible tamoxifen resistance associated with the continuous block of the oestrogen receptor signalling and the activation of PI3K/Akt pathway. We suppose that the miRNAs-ERα suppressors may act as trigger agents inducing the block of oestrogen receptor signalling and breast cancer cell transition to an aggressive oestrogen-independent state.

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

Despite their small size, the membrane-bound particles named extracellular vesicles (EVs) seem to play an enormous role in the pathogenesis of acute leukemia. From oncogenic hematopoietic stem cells (HSCs) to become leukemic cells to alter the architecture of bone marrow (BM) microenvironment, EVs are critical components of leukemia development. As a carrier of essential molecules, especially a group of small non-coding RNAs known as miRNA, recently, EVs have attracted tremendous attention as a prognostic factor. Given the importance of miRNAs in the early stages of leukemogenesis and also their critical parts in the development of drug-resistant phenotype, it seems that the importance of EVs in the development of leukemia is more than what is expected. To be familiar with the clinical value of leukemia-derived EVs, this review aimed to briefly shed light on the biology of EVs and to discuss the role of EV-derived miRNAs in the development of acute myeloid leukemia and acute lymphoblastic leukemia. By elaborating the advances and challenges concerning the isolation of EVs, we discuss whether EVs could have a prognostic value in the clinical setting for leukemia.

S. Typhi derived vaccines and a proposal for outer membrane vesicles (OMVs) as potential vaccine for typhoid fever

Typhoid fever is a serious systemic infection caused by Salmonella Typhi (S. Typhi), spread by the feco-oral route and closely associated with poor food hygiene and inadequate sanitation. Nearly 93% of S. Typhi strains have acquired antibiotic resistance against most antibiotics. Vaccination is the only promising way to prevent typhoid fever. This review covers the nature and composition of S. Typhi, pathogenecity and mode of infection, epidemiology, and nature of drug resistance. Several components (Vi-polysaccharides, O-antigens, flagellar antigens, full length OMPs, and short peptides from OMPs) of S. Typhi have been utilized for vaccine design for protection against typhoid fever. Vaccine delivery systems also contribute to efficacy of the vaccines. In this study, we propose to develop S. Typhi derived OMVs as vaccine for protection against typhoid fevers.

B-cell acute lymphoblastic leukemia-related microRNAs: uncovering their diverse and special roles

B-cell acute lymphoblastic leukemia (B-ALL) is a common type of hematologic malignancy characterized by the uncontrolled growth of immature B lymphocytes. Genomics, transcriptomics, and proteomics at different levels contribute to early diagnosis and can thereby provide better treatment for cancer. MicroRNAs (miRNAs) are conducive to the diagnosis and treatment of patients with B-ALL. Moreover, evidence suggests that runaway miRNAs and exosomes containing miRNA may be involved in the occurrence of B-ALL, which can then be used as potential biomarkers. This review summarizes the role of miRNAs in the pathogenesis, diagnosis, prognosis, and treatment of B-ALL.

CD19 Chimeric Antigen Receptor-Exosome Targets CD19 Positive B-lineage Acute Lymphocytic Leukemia and Induces Cytotoxicity

CAR-T cell therapy is not without some clinical adverse effects, namely cytokine storms, due to a massive release of cytokines when CAR-T cells multiply in the body. Our goal was to develop exosomes expressing CD19 CAR to treat CD19-positive B-cell malignancies, instead of using whole CD19 CAR-T cells, thereby reducing the clinical risk of uncontrolled cytokine storms. Exosomes are extracellular nanovesicles (30-150 nm), composed of lipids, proteins, and nucleic acids, that carry the fingerprint of their parent cells. Exosomes are a preferred delivery system in nano-immunotherapy. Here, HEK293T parent cells were transduced with CD19 CAR plasmids and cellular CD19 CAR expression was confirmed. Exosomes (Exo-CD19 CAR) were isolated from the conditioned medium of non-transduced (WT) and CD19 CAR plasmid transduced HEK293T cells. Consequently, CD19 B-lineage leukemia cell lines were co-cultured with Exo-CD19 CAR and cell death was measured. Our data show that Exo-CD19 CAR treatment induced cytotoxicity and elevated pro-apoptotic genes in CD19-positive leukemia B-cells without inducing cell death in CD19-negative cells. Overall, the novel CD19 CAR exosomes target the CD19 surface antigens of leukemic B-cells and can induce contact-dependent cytotoxicity.

Vincristine and prednisone regulates cellular and exosomal miR-181a expression differently within the first time diagnosed and the relapsed leukemia B cells

We explored the effect of vincristine and prednisone on cellular and exosomal miR-181a expression in first time diagnosed leukemia and relapsed leukemia. Vincristine and prednisone induced apoptosis/pro-apoptotic genes in first time diagnosed leukemia, and suppressed the cellular and exosomal miR-181a expression. In contrast, vincristine and prednisone could not induce apoptosis/pro-apoptotic genes in relapsed leukemia, and could not change the expression of cellular or exosomal miR-181a. In conclusion, the non-suppressive nature of miR-181a in relapsed leukemia might contribute to the chemo-resistance and this suggests a potential role of miR-181a-inhibitor along with the chemotherapy in the treatment of relapsed leukemia.