S100-A9 protein in exosomes from chronic lymphocytic leukemia cells promotes NF-κB activity during disease progression

Extracellular vesicles from oral mucosa stem cells promote lipid raft formation in human microglia through TLR4, P2X4R, and αVβ3/αVβ5 signaling pathways

Targeting of disease-associated microglia represents a promising therapeutic approach that can be used for the prevention or slowing down neurodegeneration. In this regard, the use of extracellular vesicles (EVs) represents a promising therapeutic approach. However, the molecular mechanisms by which EVs regulate microglial responses remain poorly understood. In the present study, we used EVs derived from human oral mucosa stem cells (OMSCs) to investigate the effects on the lipid raft formation and the phagocytic response of human microglial cells. Lipid raft labeling with fluorescent cholera toxin subunit B conjugates revealed that both EVs and lipopolysaccharide (LPS) by more than two times increased lipid raft formation in human microglia. By contrast, combined treatment with LPS and EVs significantly decreased lipid raft formation indicating possible interference of EVs with the process of LPS-induced lipid raft formation. Specific inhibition of Toll-like receptor 4 (TLR4) with anti-TLR4 antibody as well as inhibition of purinergic P2X4 receptor (P2X4R) with selective antagonist 5-BDBD inhibited EVs- and LPS-induced lipid raft formation. Selective blockage of αvβ3/αvβ5 integrins with cilengitide suppressed EV- and LPS-induced lipid raft formation in microglia. Furthermore, inhibition of TLR4 and P2X4R prevented EV-induced phagocytic activity of human microglial cells. We demonstrate that EVs induce lipid raft formation in human microglia through interaction with TLR4, P2X4R, and αVβ3/αVβ5 signaling pathways. Our results provide new insights about the molecular mechanisms regulating EV/microglia interactions and could be used for the development of new therapeutic strategies against neurological disorders.

Necrotic Cells from Head and Neck Carcinomas Release Biomolecules That Are Activating Toll-like Receptor 3

Tumor necrosis is a recurrent characteristic of head and neck squamous cell carcinomas (HNSCCs). There is a need for more investigations on the influence of biomolecules released by these necrotic foci in the HNSCC tumor microenvironment. It is suspected that a fraction of the biomolecules released by necrotic cells are damage-associated molecular patterns (DAMPs), which are known to be natural endogenous ligands of Toll-like receptors (TLRs), including, among others, proteins and nucleic acids. However, there has been no direct demonstration that biomolecules released by HNSCC necrotic cells can activate TLRs. Our aim was to investigate whether some of these molecules could behave as agonists of the TLR3, either in vitro or in vivo. We chose a functional approach based on reporter cell exhibiting artificial TLR3 expression and downstream release of secreted alkaline phosphatase. The production of biomolecules activating TLR3 was first investigated in vitro using three HNSCC cell lines subjected to various pronecrotic stimuli (external irradiation, serum starvation, hypoxia and oxidative stress). TLR3 agonists were also investigated in necrotic tumor fluids from five oral cancer patients and three mouse tumor grafts. The release of biomolecules activating TLR3 was demonstrated for all three HNSCC cell lines. External irradiation was the most consistently efficient stimulus, and corresponding TLR3 agonists were conveyed in extracellular vesicles. TLR3-stimulating activity was detected in the fluids from all five patients and three mouse tumor grafts. In most cases, this activity was greatly reduced by RNAse pretreatment or TLR3 blocking antibodies. Our data indicate that TLR3 agonists are consistently present in necrotic fluids from HNSCC cells and mainly made of dsRNA fragments. These endogenous agonists may induce TLR3, which might lead to a protumorigenic effect. Regarding methodological aspects, our study demonstrates that direct investigations-including functional testing-can be performed on necrotic fluids from patient tumors.

Melatonin ameliorates atherosclerosis by suppressing S100a9-mediated vascular inflammation

Atherosclerosis (AS)-associated cardiovascular diseases are predominant causes of morbidity and mortality worldwide. Melatonin, a circadian hormone with anti-inflammatory activity, may be a novel therapeutic intervention for AS. However, the exact mechanism is unclear. This research intended to investigate the mechanism of melatonin in treating AS. Melatonin (20 mg/kg/d) was intraperitoneally administered in a high-fat diet (HFD)-induced AS model using apolipoprotein E-deficient (ApoE-/-) mice for 12 weeks. Immunohistochemical and immunofluorescence analyses, data-independent acquisition (DIA)-based protein profiling, ingenuity pathway analysis (IPA), and western blotting were employed to investigate the therapeutic effects of melatonin in treating HFD-induced AS. An adeno-associated virus (AAV) vector was further used to confirm the antiatherosclerotic mechanism of melatonin. Melatonin treatment markedly attenuated atherosclerotic lesions, induced stable phenotypic sclerotic plaques, inhibited macrophage infiltration, and suppressed the production of proinflammatory cytokines in ApoE-/- mice with HFD-induced AS. Notably, DIA-based quantitative proteomics together with IPA identified S100a9 as a pivotal mediator in the protective effects of melatonin. Moreover, melatonin significantly suppressed HFD-induced S100a9 expression at both the mRNA and protein levels. The overexpression of S100a9 significantly activated the NF-κB signaling pathway and markedly abolished the antagonistic effect of melatonin on HFD-induced vascular inflammation during atherogenesis. Melatonin exerts a significant antiatherogenic effect by inhibiting S100a9/NF-κB signaling pathway-mediated vascular inflammation. Our findings reveal a novel antiatherosclerotic mechanism of melatonin and underlie its potential clinical use in modulating AS with good availability and affordability.

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.

Extracellular Vesicles in Chronic Lymphocytic Leukemia: Tumor Microenvironment Messengers as a Basis for New Targeted Therapies?

In addition to intrinsic genomic and nongenomic alterations, tumor progression is also dependent on the tumor microenvironment (TME, mainly composed of the extracellular matrix (ECM), secreted factors, and bystander immune and stromal cells). In chronic lymphocytic leukemia (CLL), B cells have a defect in cell death; contact with the TME in secondary lymphoid organs dramatically increases the B cells' survival via the activation of various molecular pathways, including the B cell receptor and CD40 signaling. Conversely, CLL cells increase the permissiveness of the TME by inducing changes in the ECM, secreted factors, and bystander cells. Recently, the extracellular vesicles (EVs) released into the TME have emerged as key arbiters of cross-talk with tumor cells. The EVs' cargo can contain various bioactive substances (including metabolites, proteins, RNA, and DNA); upon delivery to target cells, these substances can induce intracellular signaling and drive tumor progression. Here, we review recent research on the biology of EVs in CLL. EVs have diagnostic/prognostic significance and clearly influence the clinical outcome of CLL; hence, from the perspective of blocking CLL-TME interactions, EVs are therapeutic targets. The identification of novel EV inhibitors might pave the way to the development of novel combination treatments for CLL and the optimization of currently available treatments (including immunotherapy).

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.

S100A10 promotes HCC development and progression via transfer in extracellular vesicles and regulating their protein cargos

OBJECTIVE

Growing evidence indicates that tumour cells exhibit characteristics similar to their lineage progenitor cells. We found that S100 calcium binding protein A10 (S100A10) exhibited an expression pattern similar to that of liver progenitor genes. However, the role of S100A10 in hepatocellular carcinoma (HCC) progression is unclear. Furthermore, extracellular vesicles (EVs) are critical mediators of tumourigenesis and metastasis, but the extracellular functions of S100A10, particularly those related to EVs (EV-S100A10), are unknown.

DESIGN

The functions and mechanisms of S100A10 and EV-S100A10 in HCC progression were investigated in vitro and in vivo. Neutralising antibody (NA) to S100A10 was used to evaluate the significance of EV-S100A10.

RESULTS

Functionally, S100A10 promoted HCC initiation, self-renewal, chemoresistance and metastasis in vitro and in vivo. Of significance, we found that S100A10 was secreted by HCC cells into EVs both in vitro and in the plasma of patients with HCC. S100A10-enriched EVs enhanced the stemness and metastatic ability of HCC cells, upregulated epidermal growth factor receptor (EGFR), AKT and ERK signalling, and promoted epithelial-mesenchymal transition. EV-S100A10 also functioned as a chemoattractant in HCC cell motility. Of significance, S100A10 governed the protein cargos in EVs and mediated the binding of MMP2, fibronectin and EGF to EV membranes through physical binding with integrin αⅤ. Importantly, blockage of EV-S100A10 with S100A10-NA significantly abrogated these enhancing effects.

CONCLUSION

Altogether, our results uncovered that S100A10 promotes HCC progression significantly via its transfer in EVs and regulating the protein cargoes of EVs. EV-S100A10 may be a potential therapeutic target and biomarker for HCC progression.

Extracellular Vesicle Secretion by Leukemia Cells In Vivo Promotes CLL Progression by Hampering Antitumor T-cell Responses

Small extracellular vesicle (sEV, or exosome) communication among cells in the tumor microenvironment has been modeled mainly in cell culture, whereas their relevance in cancer pathogenesis and progression in vivo is less characterized. Here we investigated cancer-microenvironment interactions in vivo using mouse models of chronic lymphocytic leukemia (CLL). sEVs isolated directly from CLL tissue were enriched in specific miRNA and immune-checkpoint ligands. Distinct molecular components of tumor-derived sEVs altered CD8+ T-cell transcriptome, proteome, and metabolome, leading to decreased functions and cell exhaustion ex vivo and in vivo. Using antagomiRs and blocking antibodies, we defined specific cargo-mediated alterations on CD8+ T cells. Abrogating sEV biogenesis by Rab27a/b knockout dramatically delayed CLL pathogenesis. This phenotype was rescued by exogenous leukemic sEV or CD8+ T-cell depletion. Finally, high expression of sEV-related genes correlated with poor outcomes in CLL patients, suggesting sEV profiling as a prognostic tool. In conclusion, sEVs shape the immune microenvironment during CLL progression.

SIGNIFICANCE

sEVs produced in the leukemia microenvironment impair CD8+ T-cell mediated antitumor immune response and are indispensable for leukemia progression in vivo in murine preclinical models. In addition, high expression of sEV-related genes correlated with poor survival and unfavorable clinical parameters in CLL patients. See related commentary by Zhong and Guo, p. 5. This article is highlighted in the In This Issue feature, p. 1.

Comparative Proteomic Analysis of Milk-Derived Extracellular Vesicles from Dairy Cows with Clinical and Subclinical Mastitis

Extracellular vesicles (EVs) are membranous vesicles found in biological fluids with essential functions. However, milk-derived EV proteins from clinical mastitis (CM) and subclinical mastitis (SM) cows have yet to be studied in detail. In this study, milk-derived EVs of CM, SM, and Healthy cows were extracted using a combination of acetic acid/ultracentrifugation and density gradient ultracentrifugation and analyzed using a shotgun proteomic by data-independent acquisition mode. A total of 1253 milk exosome proteins were identified and quantified. Differently enriched (DE) proteins were identified as given a Benjamini−Hochberg adjusted p < 0.05 and a fold change of at least 2. There were 53 and 1 DE proteins in milk-derived EVs from CM and SM cows compared with healthy cows. Protein S100-A9, Protein S100-A8, Chitinase-3-like protein 1, Haptoglobin, Integrin beta-2, and Chloride intracellular channel protein 1 were more abundant in the CM group (adjusted p < 0.05). Still, their enrichment in the SM group was not significant as in the Healthy group. The enrichment of DE proteins between CM and Healthy group was consistent with elevated GO (Gene Ontology) processes—defense response, defense response to Gram-positive bacterium, granulocyte chemotaxis also contributed to Reactome pathways—neutrophil degranulation, innate immune system, and antimicrobial peptides in the CM group. These results provide essential information on mastitis-associated proteins in milk-derived EVs and indicate the biological functions of milk-derived EVs proteins require further elucidation.

S100 Proteins as Novel Therapeutic Targets in Psoriasis and Other Autoimmune Diseases

Psoriasis is one of the most common inflammatory skin diseases affecting about 1-3% of the population. One of the characteristic abnormalities in psoriasis is the excessive production of antimicrobial peptides and proteins, which play an essential role in the pathogenesis of the disease. Antimicrobial peptides and proteins can be expressed differently in normal and diseased skin, reflecting their usefulness as diagnostic biomarkers. Moreover, due to their very important functions in innate immunity, members of host defense peptides and proteins are currently considered to be promising new therapeutic targets for many inflammatory diseases. Koebnerisin (S100A15) belongs to an S100 family of antimicrobial proteins, which constitute the multigenetic group of calcium-binding proteins involved in ion-dependent cellular functions and regulation of immune mechanisms. S100A15 was first discovered to be overexpressed in 'koebnerized' psoriatic skin, indicating its involvement in the disease phenotype and the same promising potential as a new therapeutic target. This review describes the involvement of antimicrobial peptides and proteins in inflammatory diseases' development and therapy. The discussion focuses on S100 proteins, especially koebnerisin, which may be involved in the underlying mechanism of the Köebner phenomenon in psoriasis, as well as other immune-mediated inflammatory diseases described in the last decade.

Emerging roles of extracellular vesicles in normal and malignant hematopoiesis

Hematopoietic stem cells, regulated by their microenvironment (or “niche”), sustain the production of mature blood and immune cells. Leukemia cells remodel the microenvironment to enhance their survival, which is accompanied by the loss of support for normal hematopoiesis in hematologic malignancies. Extracellular vesicles (EVs) mediate intercellular communication in physiological and pathological conditions, and deciphering their functions in cell-cell interactions in the ecosystem can highlight potential therapeutic targets. In this Review, we illustrate the utility of EVs derived from various cell types, focusing on the biological molecules they contain and the behavioral alterations they can induce in recipient cells. We also discuss the potential for clinical application in hematologic malignancies, including EV-based therapeutic regimens, drug delivery via EVs, and the use of EVs (or their cargoes) as biomarkers.

Regulation of S100As Expression by Inflammatory Cytokines in Chronic Lymphocytic Leukemia

The calcium-binding proteins S100A4, S100A8, and S100A9 are upregulated in chronic lymphocytic leukemia (CLL), while the S100A9 promotes NF-κB activity during disease progression. The S100-protein family has been involved in several malignancies as mediators of inflammation and proliferation. The hypothesis of our study is that S100A proteins are mediators in signaling pathways associated with inflammation-induced proliferation, such as NF-κB, PI3K/AKT, and JAK/STAT. The mononuclear cells (MNCs) of CLL were treated with proinflammatory IL-6, anti-inflammatory IL-10 cytokines, inhibitors of JAK1/2, NF-κB, and PI3K signaling pathways, to evaluate S100A4, S100A8, S100A9, and S100A12 expression as well as NF-κB activation by qRT-PCR, immunocytochemistry, and immunoblotting. The quantity of S100A4, S100A8, and S100A9 positive cells (p < 0.05) and their protein expression (p < 0.01) were significantly decreased in MNCs of CLL patients compared to healthy controls. The S100A levels were generally increased in CD19+ cells compared to MNCs of CLL. The S100A4 gene expression was significantly stimulated (p < 0.05) by the inhibition of the PI3K/AKT signaling pathway in MNCs. IL-6 stimulated S100A4 and S100A8 protein expression, prevented by the NF-κB and JAK1/2 inhibitors. In contrast, IL-10 reduced S100A8, S100A9, and S100A12 protein expressions in MNCs of CLL. Moreover, IL-10 inhibited activation of NF-κB signaling (4-fold, p < 0.05). In conclusion, inflammation stimulated the S100A protein expression mediated via the proliferation-related signaling and balanced by the cytokines in CLL.

Update on the role and utility of extracellular vesicles in hematological malignancies

Extracellular vesicles (EVs) are membrane-surrounded cellular particles released by virtually any cell type, containing numerous bioactive molecules, including lipids, proteins, and nucleic acids. EVs act as a very efficient intercellular communication system by releasing their content into target cells, thus affecting their fate and influencing several biological processes. EVs are released both in physiological and pathological conditions, including several types of cancers. In hematological malignancies (HM), EVs have emerged as new critical players, contributing to tumor-to-stroma, stroma-to-tumor, and tumor-to-tumor cell communication. Therefore, EVs have been shown to play a crucial role in the pathogenesis and clinical course of several HM, contributing to tumor development, progression, and drug resistance. Furthermore, tumor EVs can reprogram the bone marrow (BM) microenvironment and turn it into a sanctuary, in which cancer cells suppress both the normal hematopoiesis and the immunological anti-tumor activity, conferring a therapy-resistant phenotype. Due to their physicochemical characteristics and pro-tumor properties, EVs have been suggested as new diagnostic biomarkers, therapeutic targets, and pharmacological nanocarriers. This review aims to provide an update on the pathogenetic contribution and the putative therapeutic utility of EVs in hematological diseases.

TGF-β/SMAD Pathway Is Modulated by miR-26b-5p: Another Piece in the Puzzle of Chronic Lymphocytic Leukemia Progression

Simple Summary

TGF-β is a key immunoregulatory pathway that can limit the proliferation of B-lymphocytes. Chronic lymphocytic leukemia (CLL) has been historically conceptualized as a neoplasm characterized by accumulation of mature B cells escaping programmed cell death and undergoing cell-cycle arrest in the G0/G1 phase. However, new evidence indicates that tumor expansion is in fact a dynamic process in which cell proliferation also plays an important role. In general, cancers progress by the emergence of subclones with genomic aberrations distinct from the initial tumor. Often, these subclones are selected for advantages in cell survival and/or growth. Here, we provide novel evidence to explain, at least in part, the origins of CLL progression in a subgroup of patients with a poor clinical outcome. In this cohort, the immunoregulatory pathway TGF-β/SMAD is modulated by miR-26b-5p and the impairment of this axis bypasses cell cycle arrest in CLL cells facilitating disease progression.

Abstract

Clinical and molecular heterogeneity are hallmarks of chronic lymphocytic leukemia (CLL), a neoplasm characterized by accumulation of mature and clonal long-lived CD5 + B-lymphocytes. Mutational status of the IgHV gene of leukemic clones is a powerful prognostic tool in CLL, and it is well established that unmutated CLLs (U-CLLs) have worse evolution than mutated cases. Nevertheless, progression and treatment requirement of patients can evolve independently from the mutational status. Microenvironment signaling or epigenetic changes partially explain this different behavior. Thus, we think that detailed characterization of the miRNAs landscape from patients with different clinical evolution could facilitate the understanding of this heterogeneity. Since miRNAs are key players in leukemia pathogenesis and evolution, we aim to better characterize different CLL behaviors by comparing the miRNome of clinically progressive U-CLLs vs. stable U-CLLs. Our data show up-regulation of miR-26b-5p, miR-106b-5p, and miR-142-5p in progressive cases and indicate a key role for miR-26b-5p during CLL progression. Specifically, up-regulation of miR-26b-5p in CLL cells blocks TGF-β/SMAD pathway by down-modulation of SMAD-4, resulting in lower expression of p21^−Cip1 kinase inhibitor and higher expression of c-Myc oncogene. This work describes a new molecular mechanism linking CLL progression with TGF-β modulation and proposes an alternative strategy to explore in CLL therapy.

Extracellular Vesicles as Central Mediators of COPD Pathophysiology

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous, smoking-related disease of significant global impact. The complex biology of COPD is ultimately driven by a few interrelated processes, including proteolytic tissue remodeling, innate immune inflammation, derangements of the host-pathogen response, aberrant cellular phenotype switching, and cellular senescence, among others. Each of these processes are engendered and perpetuated by cells modulating their environment or each other. Extracellular vesicles (EVs) are powerful effectors that allow cells to perform a diverse array of functions on both adjacent and distant tissues, and their pleiotropic nature is only beginning to be appreciated. As such, EVs are candidates to play major roles in these fundamental mechanisms of disease behind COPD. Furthermore, some such roles for EVs are already established, and EVs are implicated in significant aspects of COPD pathogenesis. Here, we discuss known and potential ways that EVs modulate the environment of their originating cells to contribute to the processes that underlie COPD.

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.

Extracellular Vesicles and DAMPs in Cancer: A Mini-Review

Certain cancer therapy has been shown to induce immunogenic cell death in cancer cells and may promote tumor progression instead. The external stress or stimuli may induce cell death and contribute toward the secretion of pro inflammatory molecules. The release of damage-associated molecular patterns (DAMPs) upon induction of therapy or cell death has been shown to induce an inflammatory response. Nevertheless, the mechanism as to how the DAMPs are released and engage in such activity needs further in-depth investigation. Interestingly, some studies have shown that DAMPs can be released through extracellular vesicles (EVs) and can bind to receptors such as toll-like receptors (TCRs). Ample pre-clinical studies have shown that cancer-derived EVs are able to modulate immune responses within the tumor microenvironment. However, the information on the presence of such DAMPs within EVs is still elusive. Therefore, this mini-review attempts to summarize and appraise studies that have shown the presence of DAMPs within cancer-EVs and how it affects the downstream cellular process.

Nonvalvular atrial fibrillation patients anticoagulated with rivaroxaban compared with warfarin exhibit reduced circulating extracellular vesicles with attenuated pro-inflammatory protein signatures

BACKGROUND

Rivaroxaban, a direct oral factor Xa inhibitor, mediates anti-inflammatory and cardiovascular-protective effects besides its well-established anticoagulant properties; however, these remain poorly characterized. Extracellular vesicles (EVs) are important circulating messengers regulating a myriad of biological and pathological processes and may be highly relevant to the pathophysiology of atrial fibrillation as they reflect alterations in platelet and endothelial biology. However, the effects of rivaroxaban on circulating pro-inflammatory EVs remain unknown.

OBJECTIVES

We hypothesized that rivaroxaban's anti-inflammatory properties are reflected upon differential molecular profiles of circulating EVs.

METHODS

Differences in circulating EV profiles were assessed using a combination of single vesicle analysis by Nanoparticle Tracking Analysis and flow cytometry, and proteomics.

RESULTS

We demonstrate, for the first time, that rivaroxaban-treated non-valvular atrial fibrillation (NVAF) patients (n=8) exhibit attenuated inflammation compared with matched warfarin controls (n=15). Circulating EV profiles were fundamentally altered. Moreover, quantitative proteomic analysis of enriched plasma EVs from six pooled biological donors per treatment group revealed a profound decrease in highly pro-inflammatory protein expression and complement factors, together with increased expression of negative regulators of inflammatory pathways. Crucially, a reduction in circulating levels of soluble P-selectin was observed in rivaroxaban-treated patients (compared with warfarin controls), which negatively correlated with the patient's time on treatment.

CONCLUSION

Collectively, these data demonstrate that NVAF patients anticoagulated with rivaroxaban (compared with warfarin) exhibit both a reduced pro-inflammatory state and evidence of reduced endothelial activation. These findings are of translational relevance toward characterizing the anti-inflammatory and cardiovascular-protective mechanisms associated with rivaroxaban therapy.

Circulating microRNAs as biomarkers in bile-derived exosomes of cholangiocarcinoma

Purpose

In this pilot study, using next-generation sequencing and integrated messenger RNA (mRNA) sequencing, we investigated circulating microRNA (miRNA) expression profiling from bile-derived exosomes to identify dysregulated miRNA signatures and oncogenic pathways and determine their effects on targeted mRNAs in cholangiocarcinoma (CCA). Moreover, we explored the possibility that genetic analysis using bile-derived exosomes may replace gene analysis using tissue.

Methods

Bile was collected from a patient with perihilar CCA before curative resection. As a control, bile was collected from a patient with a common bile duct stone. Exosomes were isolated from the bile, and we performed next-generation miRNA sequencing using isolated exosomes. To evaluate miRNA-mRNA interactions, mRNA sequencing was performed using bile fluid in both patients.

Results

We identified 22 differentially expressed miRNAs. More than 65% of the predicted mRNA targets of those miRNAs were actually differentially expressed between control and CCA bile samples. In functional pathway analysis, targets of 22 miRNAs were primarily enriched in mitogen-activated protein kinase, platelet derived growth factor, vascular endothelial growth factor, epidermal growth factor receptor, and p53 signaling. In particular, in the functional assessment of miRNA-mRNA interactions, RAS pathways, including downstream pathways (PI3K-AKT-mTOR and RAS-RAF-MEK-ERK), were determined to be enriched.

Conclusion

Circulating miRNAs in bile-derived exosomes provide new information for the development of miRNA analysis in CCA. These miRNAs may represent the oncogenic characteristics of CCA tissue, enabling them to be used instead of tissue samples for the diagnosis of CCA. Further research investigating circulating miRNAs in bile exosomes may lead to more rational, targeted approaches to treatment.

CD30-Positive Extracellular Vesicles Enable the Targeting of CD30-Negative DLBCL Cells by the CD30 Antibody-Drug Conjugate Brentuximab Vedotin

CD30, a member of the TNF receptor superfamily, is selectively expressed on a subset of activated lymphocytes and on malignant cells of certain lymphomas, such as classical Hodgkin Lymphoma (cHL), where it activates critical bystander cells in the tumor microenvironment. Therefore, it is not surprising that the CD30 antibody-drug conjugate Brentuximab Vedotin (BV) represents a powerful, FDA-approved treatment option for CD30⁺ hematological malignancies. However, BV also exerts a strong anti-cancer efficacy in many cases of diffuse large B cell lymphoma (DLBCL) with poor CD30 expression, even when lacking detectable CD30⁺ tumor cells. The mechanism remains enigmatic. Because CD30 is released on extracellular vesicles (EVs) from both, malignant and activated lymphocytes, we studied whether EV-associated CD30 might end up in CD30^– tumor cells to provide binding sites for BV. Notably, CD30⁺ EVs bind to various DLBCL cell lines as well as to the FITC-labeled variant of the antibody-drug conjugate BV, thus potentially conferring the BV binding also to CD30^– cells. Confocal microscopy and imaging cytometry studies revealed that BV binding and uptake depend on CD30⁺ EVs. Since BV is only toxic toward CD30^– DLBCL cells when CD30⁺ EVs support its uptake, we conclude that EVs not only communicate within the tumor microenvironment but also influence cancer treatment. Ultimately, the CD30-based BV not only targets CD30⁺ tumor cell but also CD30^– DLBCL cells in the presence of CD30⁺ EVs. Our study thus provides a feasible explanation for the clinical impact of BV in CD30^– DLBCL and warrants confirming studies in animal models.

Clinical Proteomics of Biofluids in Haematological Malignancies

Since the emergence of high-throughput proteomic techniques and advances in clinical technologies, there has been a steady rise in the number of cancer-associated diagnostic, prognostic, and predictive biomarkers being identified and translated into clinical use. The characterisation of biofluids has become a core objective for many proteomic researchers in order to detect disease-associated protein biomarkers in a minimally invasive manner. The proteomes of biofluids, including serum, saliva, cerebrospinal fluid, and urine, are highly dynamic with protein abundance fluctuating depending on the physiological and/or pathophysiological context. Improvements in mass-spectrometric technologies have facilitated the in-depth characterisation of biofluid proteomes which are now considered hosts of a wide array of clinically relevant biomarkers. Promising efforts are being made in the field of biomarker diagnostics for haematologic malignancies. Several serum and urine-based biomarkers such as free light chains, β-microglobulin, and lactate dehydrogenase are quantified as part of the clinical assessment of haematological malignancies. However, novel, minimally invasive proteomic markers are required to aid diagnosis and prognosis and to monitor therapeutic response and minimal residual disease. This review focuses on biofluids as a promising source of proteomic biomarkers in haematologic malignancies and a key component of future diagnostic, prognostic, and disease-monitoring applications.

AID overexpression leads to aggressive murine CLL and nonimmunoglobulin mutations that mirror human neoplasms

Most cancers become more dangerous by the outgrowth of malignant subclones with additional DNA mutations that favor proliferation or survival. Using chronic lymphocytic leukemia (CLL), a disease that exemplifies this process and is a model for neoplasms in general, we created transgenic mice overexpressing the enzyme activation-induced deaminase (AID), which has a normal function of inducing DNA mutations in B lymphocytes. AID not only allows normal B lymphocytes to develop more effective immunoglobulin-mediated immunity, but is also able to mutate nonimmunoglobulin genes, predisposing to cancer. In CLL, AID expression correlates with poor prognosis, suggesting a role for this enzyme in disease progression. Nevertheless, direct experimental evidence identifying the specific genes that are mutated by AID and indicating that those genes are associated with disease progression is not available. To address this point, we overexpressed Aicda in a murine model of CLL (Eμ-TCL1). Analyses of TCL1/AID mice demonstrate a role for AID in disease kinetics, CLL cell proliferation, and the development of cancer-related target mutations with canonical AID signatures in nonimmunoglobulin genes. Notably, our mouse models can accumulate mutations in the same genes that are mutated in human cancers. Moreover, some of these mutations occur at homologous positions, leading to identical or chemically similar amino acid substitutions as in human CLL and lymphoma. Together, these findings support a direct link between aberrant AID activity and CLL driver mutations that are then selected for their oncogenic effects, whereby AID promotes aggressiveness in CLL and other B-cell neoplasms.

Proteomics and Drug Repurposing in CLL towards Precision Medicine

Simple Summary

Despite continued efforts, the current status of knowledge in CLL molecular pathobiology, diagnosis, prognosis and treatment remains elusive and imprecise. Proteomics approaches combined with advanced bioinformatics and drug repurposing promise to shed light on the complex proteome heterogeneity of CLL patients and mitigate, improve, or even eliminate the knowledge stagnation. In relation to this concept, this review presents a brief overview of all the available proteomics and drug repurposing studies in CLL and suggests the way such studies can be exploited to find effective therapeutic options combined with drug repurposing strategies to adopt and accost a more “precision medicine” spectrum.

Abstract

CLL is a hematological malignancy considered as the most frequent lymphoproliferative disease in the western world. It is characterized by high molecular heterogeneity and despite the available therapeutic options, there are many patient subgroups showing the insufficient effectiveness of disease treatment. The challenge is to investigate the individual molecular characteristics and heterogeneity of these patients. Proteomics analysis is a powerful approach that monitors the constant state of flux operators of genetic information and can unravel the proteome heterogeneity and rewiring into protein pathways in CLL patients. This review essences all the available proteomics studies in CLL and suggests the way these studies can be exploited to find effective therapeutic options combined with drug repurposing approaches. Drug repurposing utilizes all the existing knowledge of the safety and efficacy of FDA-approved or investigational drugs and anticipates drug alignment to crucial CLL therapeutic targets, leading to a better disease outcome. The drug repurposing studies in CLL are also discussed in this review. The next goal involves the integration of proteomics-based drug repurposing in precision medicine, as well as the application of this procedure into clinical practice to predict the most appropriate drugs combination that could ensure therapy and the long-term survival of each CLL patient.

Acute lymphoblastic leukemia-derived exosome inhibits cytotoxicity of natural killer cells by TGF-β signaling pathway

This study was conducted to explore whether acute lymphoblastic leukemia (ALL)-derived exosomes affect natural killer (NK) cells. Exosomes were isolated and identified from Jurkat cells and co-cultured with NK cells. Then, the cytotoxicity, viability, and release of perforin and granzyme B in NK92-MI cells were measured. PCR arrays were used to detect gene expression alterations in the transforming growth factor (TGF)-β pathway of NK92-MI cells treated or not treated with exosomes. The morphology and size of the exosomes isolated from Jurkat cells showed typical characteristics of exosomes, and the expression of cluster of differentiation 63 was detected. Jurkat-derived exosomes were internalized by NK92-MI cells, further inhibiting the proliferation and cytotoxicity of NK92-MI cells. An enzyme-linked immunosorbent assay revealed that the release of perforin and granzyme B from NK92-MI cells decreased after co-culture with exosomes. Similarly, western blot and immunofluorescence staining verified that Jurkat-derived exosomes inhibited the expression of granzyme B and perforin. Furthermore, Jurkat-derived exosomes enhanced the signaling of the TGF-β pathway in NK92-MI cells via the MDS1 and EVI1 complex loci and homeodomain interacting protein kinase 2. In conclusion, we found that ALL-derived exosomes inhibit the biological function of NK cells and provide support for the immunotherapy of ALL.

The roles of tumor-derived exosomes in altered differentiation, maturation and function of dendritic cells

Tumor-derived exosomes (TDEs) have been shown to impede anti-tumor immune responses via their immunosuppressive cargo. Since dendritic cells (DCs) are the key mediators of priming and maintenance of T cell-mediated responses; thus it is logical that the exosomes released by tumor cells can exert a dominant influence on DCs biology. This paper intends to provide a mechanistic insight into the TDEs-mediated DCs abnormalities in the tumor context. More importantly, we discuss extensively how tumor exosomes induce subversion of DCs differentiation, maturation and function in separate sections. We also briefly describe the importance of TDEs at therapeutic level to help guide future treatment options, in particular DC-based vaccination strategy, and review advances in the design and discovery of exosome inhibitors. Understanding the exosomal content and the pathways by which TDEs are responsible for immune evasion may help to revise treatment rationales and devise novel therapeutic approaches to overcome the hurdles in cancer treatment.

Reviewing the role of cardiac exosomes in myocardial repair at a glance

Exosome-based therapy is an emerging novel approach for myocardial infarction (MI) treatment. Exosomes are identified as extracellular vesicles that are produced within multivesicular bodies in the cells' cytosols and then are secreted from the cells. Exosomes are 30-100 nm in diameter that are released from viable cells and are different from other secreted vesicles such as apoptotic bodies and microvesicles in their origin and contents such as RNAs, proteins, and nucleic acid. The recent advances in exosome research have demonstrated the role of these bionanovesicles in the physiological, pathological, and molecular aspects of the heart. The results of in vitro and preclinical models have shown that exosomes from different cardiac cells can improve cardiac function following MI. For example, mesenchymal stem cells (MSCs) and cardiac progenitor cells (CPCs) containing exosomes can affect the proliferation, survival, and differentiation of cardiac fibroblasts and cardiomyocytes. Moreover, MSCs- and CPCs-derived exosomes can enhance the migration of endothelial cells. Exosome-based therapy approaches augment the cardiac function by multiple means, such as reducing fibrosis, stimulation of vascular angiogenesis, and proliferation of cardiomyocytes that result in replacing damaged heart tissue with newly generated functional myocytes. This review article aims to briefly discuss the recent advancements in the role of secreted exosomes in myocardial repair by focusing on cardiac cells-derived exosomes.

The "Vesicular Intelligence" Strategy of Blood Cancers

Blood cancers are a heterogeneous group of disorders including leukemia, multiple myeloma, and lymphoma. They may derive from the clonal evolution of the hemopoietic stem cell compartment or from the transformation of progenitors with immune potential. Extracellular vesicles (EVs) are membrane-bound nanovesicles which are released by cells into body fluids with a role in intercellular communication in physiology and pathology, including cancer. EV cargos are enriched in nucleic acids, proteins, and lipids, and these molecules can be delivered to target cells to influence their biological properties and modify surrounding or distant targets. In this review, we will describe the “smart strategy” on how blood cancer-derived EVs modulate tumor cell development and maintenance. Moreover, we will also depict the function of microenvironment-derived EVs in blood cancers and discuss how the interplay between tumor and microenvironment affects blood cancer cell growth and spreading, immune response, angiogenesis, thrombogenicity, and drug resistance. The potential of EVs as non-invasive biomarkers will be also discussed. Lastly, we discuss the clinical application viewpoint of EVs in blood cancers. Overall, blood cancers apply a ‘vesicular intelligence’ strategy to spread signals over their microenvironment, promoting the development and/or maintenance of the malignant clone.

Clinical relevance of extracellular vesicles in hematological neoplasms: from liquid biopsy to cell biopsy

In the era of precision medicine, liquid biopsy is becoming increasingly important in oncology. It consists in the isolation and analysis of tumor-derived biomarkers, including extracellular vesicles (EVs), in body fluids. EVs are lipid bilayer-enclosed particles, heterogeneous in size and molecular composition, released from both normal and neoplastic cells. In tumor context, EVs are valuable carriers of cancer information; in fact, their amount, phenotype and molecular cargo, including proteins, lipids, metabolites and nucleic acids, mirror nature and origin of parental cells rendering EVs appealing candidates as novel biomarkers. Translation of these new potential diagnostic tools into clinical practice could deeply revolutionize the cancer field mainly for solid tumors but for hematological neoplasms, too.

Syntaxin 2 promotes colorectal cancer growth by increasing the secretion of exosomes

Background: Colorectal cancer (CRC) is one of the most common cancers with high mortality worldwide. Uncontrolled growth is an important hallmark of CRC. However, the mechanisms are poorly understood. Methods: Syntaxin 2 (STX2) expression was analyzed in 160 cases of paraffin-embedded CRC tissue by immunohistochemistry, in 10 cases of fresh CRC tissue by western blot, and in 2 public databases. Gain- and loss-of-function analyses were used to investigate the biological function of STX2 in CRC growth. Exosomes isolation, characterization, Co-immunoprecipitation (Co-IP), flow cytometry and fluorescence were conducted to study the molecular mechanism of STX2 in CRC growth. Results: The expression of STX2 was obviously up-regulated in human CRC tissues. Overexpression of STX2 increased the growth of CRC cells in vitro and in vivo. Downregulation of STX2 repressed the growth of CRC. STX2 modulated exosomes secretion of CRC cells which might correlated with Rab8a expression. The secreted exosomes could be ingested by CRC cells, and ultimately promoted the growth of CRC by arresting the tumor cells at S phase. Conclusions: Our data provide evidence that STX2 promotes CRC growth by increasing exosomes secretion of CRC cells; And the modulation of STX2 in exosomes secretion correlates with Rab8a. Thus, our study identified a new mechanism of STX2 in CRC growth and may provide a possible strategy for CRC therapy.

The Calcitriol/Vitamin D Receptor System Regulates Key Immune Signaling Pathways in Chronic Lymphocytic Leukemia

Simple Summary

Calcitriol, the biologically active form of vitamin D, modulates a plethora of cellular processes following its receptor ligation, namely the vitamin D receptor (VDR). Epidemiological studies have linked low blood levels of vitamin D to adverse disease outcome in several B cell malignancies, including chronic lymphocytic leukemia (CLL), for as yet undetermined reasons. In this study, we sought to obtain deeper biological insight into the role of vitamin D in the pathophysiology of CLL. To this end, we investigated whether the calcitriol/VDR system is functional in CLL and analyzed key signaling pathways that are regulated by calcitriol supplementation, while also exploring the role of microenvironmental signals in the regulation of calcitriol/VDR system. Overall, we provide evidence that the calcitriol/VDR system is functional in CLL, regulating signaling pathways critical for cell survival/proliferation. Although microenvironmental triggers can modulate VDR expression and function, calcitriol appears to act independently, alluding to a potential clinical utility of vitamin D supplementation in CLL.

Abstract

It has been proposed that vitamin D may play a role in prevention and treatment of cancer while epidemiological studies have linked vitamin D insufficiency to adverse disease outcomes in various B cell malignancies, including chronic lymphocytic leukemia (CLL). In this study, we sought to obtain deeper biological insight into the role of vitamin D and its receptor (VDR) in the pathophysiology of CLL. To this end, we performed expression analysis of the vitamin D pathway molecules; complemented by RNA-Sequencing analysis in primary CLL cells that were treated in vitro with calcitriol, the biologically active form of vitamin D. In addition, we examined calcitriol effects ex vivo in CLL cells cultured in the presence of microenvironmental signals, namely anti-IgM/CD40L, or co-cultured with the supportive HS-5 cells; and, CLL cells from patients under ibrutinib treatment. Our study reports that the calcitriol/VDR system is functional in CLL regulating signaling pathways critical for cell survival and proliferation, including the TLR and PI3K/AKT pathways. Moreover, calcitriol action is likely independent of the microenvironmental signals in CLL, since it was not significantly affected when combined with anti-IgM/CD40L or in the context of the co-culture system. This finding was also supported by our finding of preserved calcitriol signaling capacity in CLL patients under ibrutinib treatment. Overall, our results indicate a relevant biological role for vitamin D in CLL pathophysiology and allude to the potential clinical utility of vitamin D supplementation in patients with CLL.

Roles of Bile-Derived Exosomes in Hepatobiliary Disease

Exosomes are vesicles with a diameter of 30-150 nm produced by living cells and secreted into the extracellular matrix. Exosomes mediate cellular communication by carrying active molecules, such as nucleic acids, proteins, and liposomes. Although exosomes are found in various body fluids, little is known about bile-derived exosomes. This review is the first to summarize the methods of bile storage and isolation of biliary exosomes, highlighting the roles of bile-derived exosomes, especially exosomal noncoding RNAs, in physiological and disease states and discussing their potential clinical applications.

High-throughput analysis and functional interpretation of extracellular vesicle content in hematological malignancies

Extracellular vesicles (EVs) are membrane-coated particles secreted by virtually all cell types in response to different stimuli, both in physiological and pathological conditions. Their content generally reflects their biological functions and includes a variety of molecules, such as nucleic acids, proteins and cellular components. The role of EVs as signaling vehicles has been widely demonstrated. In particular, they are actively involved in the pathogenesis of several hematological malignancies (HM), mainly interacting with a number of target cells and inducing functional and epigenetic changes. In this regard, by releasing their cargo, EVs play a pivotal role in the bilateral cross-talk between tumor microenvironment and cancer cells, thus facilitating mechanisms of immune escape and supporting tumor growth and progression. Recent advances in high-throughput technologies have allowed the deep characterization and functional interpretation of EV content. In this review, the current knowledge on the high-throughput technology-based characterization of EV cargo in HM is summarized.

Role of Chronic Lymphocytic Leukemia (CLL)-Derived Exosomes in Tumor Progression and Survival

Chronic lymphocytic leukemia (CLL) is a B-lymphoproliferative disease, which consists of the abnormal proliferation of CD19/CD5/CD20/CD23 positive lymphocytes in blood and lymphoid organs, such as bone marrow, lymph nodes and spleen. The neoplastic transformation and expansion of tumor B cells are commonly recognized as antigen-driven processes, mediated by the interaction of antigens with the B cell receptor (BCR) expressed on the surface of B-lymphocytes. The survival and progression of CLL cells largely depend on the direct interaction of CLL cells with receptors of accessory cells of tumor microenvironment. Recently, much interest has been focused on the role of tumor release of small extracellular vesicles (EVs), named exosomes, which incorporate a wide range of biologically active molecules, particularly microRNAs and proteins, which sustain the tumor growth. Here, we will review the role of CLL-derived exosomes as diagnostic and prognostic biomarkers of the disease.

Exosome: From leukemia progression to a novel therapeutic approach in leukemia treatment

Exosomes, as small vesicles, are released by tumor cells and tumor microenvironment (cells and function as key intercellular mediators and effects on different processes including tumorigenesis, angiogenesis, drug resistance, and evasion from immune system. These functions are due to exosomes' biomolecules which make them as efficient markers in early diagnosis of the disease. Also, exosomes have been recently applied in vaccination. The potential role of exosomes in immune response toward leukemic cells makes them efficient immunotherapeutic agents treating leukemia. Furthermore, variations in exosomes contents make them beneficial to be used in treating different diseases. This review introduces the role of exosomes in the development of hematological malignancies and evaluates their functional role in the treatment of these malignancies.

The regulatory role of exosomes in leukemia and their clinical significance

Recurrence is a primary cause of death in patients with leukemia. The interactions of tumor cells with the microenvironment and tumor stem cells hidden in bone marrow promote the recurrence and metastasis of leukemia to lymphoid tissue. Exosomes, membrane-coated nanovesicles secreted by living cells, perform biomaterial transfer and information exchange between cells. Exosomes contain various other biological components derived from parental cells, and they remotely regulate the function of target cells through body fluid flow. Recent studies revealed that exosomes participate in the development of leukemia and play important roles in its diagnosis and treatment by influencing cell proliferation and apoptosis, regulating bone marrow microenvironment, promoting angiogenesis, and inhibiting hematopoiesis. Exosomes are potential biomarkers and therapeutic targets for leukemia, and they can influence drug resistance. Leukemia-derived exosomes present leukemia-related antigens to target cells, promote the proliferation of leukemic cells, help these cells escape immunity, protect them from the cytotoxic effects of chemotherapeutics, and promote angiogenesis and tumor migration. Therefore, exosomes are closely related to the metastasis, treatment, and prognosis of leukemia, and they can be used to detect and monitor the progression of leukemia. This paper reviews the regulatory roles of exosomes in leukemia and their clinical significance.

Exosomal CLIC1 released by CLL promotes HUVECs angiogenesis by regulating ITGβ1-MAPK/ERK axis

Accumulating evidences have suggested that exosomes are closely associated with tumor progression by affecting cell-cell communication. Here, we aimed to investigate the roles and regulatory mechanism of exosomes released from chronic lymphocytic leukemia (CLL). The expression levels of genes and proteins in cells and exosomes were examined by quantitative real-time PCR and Western blotting, respectively. MEC-1 cell-derived exosomes were obtained and co-cultured with human umbilical vein endothelial cells (HUVECs), then the capabilities of cell proliferation, metastasis and angiogenesis of HUVECs were measured by CCK-8, wound healing, transwell and tube formation assay, respectively. Chloride intracellular channel 1 (CLIC1) was significantly increased in CLL patients and markedly enriched in exosomes secreted by CLL cells. Exosomal CLIC1 secreted from MEC-1 cells were successfully transferred into HUVECs and significantly promoted the phenotypes of proliferation, metastasis and angiogenesis of HUVECs. Mechanically, exosomal CLIC1 secreted from MEC-1 cells obviously activated MAPK/ERK signaling through upregulating integrin β1 (ITGβ1) expression in HUVECs. Furthermore, rescue experiments revealed that either silencing ITGβ1 or PD98059 treatment obviously reversed the regulatory effects of exosomal CLIC1 secreted from MEC-1 cells in HUVECs. In conclusion, CLL cell-derived exosomes accelerated HUVECs metastasis and angiogenesis through transferring CLIC1 to regulate ITGβ1-MAPK/ERK signaling, indicating that CLIC1 may be a therapeutic target of CLL exosomes in the tumor microenvironment.

Uncovering the Exosomes Diversity: A Window of Opportunity for Tumor Progression Monitoring

Cells can communicate through special “messages in the bottle”, which are recorded in the bloodstream inside vesicles, namely exosomes. The exosomes are nanovesicles of 30–100 nm in diameter that carry functionally active biological material, such as proteins, messanger RNA (mRNAs), and micro RNA (miRNAs). Therefore, they are able to transfer specific signals from a parental cell of origin to the surrounding cells in the microenvironment and to distant organs through the circulatory and lymphatic stream. More and more interest is rising for the pathological role of exosomes produced by cancer cells and for their potential use in tumor monitoring and patient follow up. In particular, the exosomes could be an appropriate index of proliferation and cancer cell communication for monitoring the minimal residual disease, which cannot be easily detectable by common diagnostic and monitoring techniques. The lack of unequivocal markers for tumor-derived exosomes calls for new strategies for exosomes profile characterization aimed at the adoption of exosomes as an official tumor biomarker for tumor progression monitoring.

Biological activities of commercial bovine lactoferrin sources

Lactoferrin (Lf) samples from several manufacturers were evaluated in vitro. The purity and protein form of each Lf were examined by SDS-PAGE, Western blot, and proteomics analysis. Assays were conducted to evaluate uptake of Lfs and iron from Lfs by enterocytes as well as Lf bioactivities, including effects on intestinal cell proliferation and differentiation, IL-18 secretion, TGF-β1 transcription, and growth of enteropathogenic Escherichia coli (EPEC). Composition of the Lfs varies; some only contain a major Lf band (∼80 kDa), and some also contain minor forms. All Lfs and iron from the Lfs were absorbed by Caco-2 cells, with various efficiencies. The bioactivities of the Lfs varied considerably, but there was no consistent trend. All Lfs promoted intestinal cell proliferation, secretion of IL-18, and transcription of TGF-β1. Some Lfs exhibited pro-differentiation effects on Caco-2 cells. Effects of pasteurization (62.5 °C for 30 min, 72 °C for 15 s, or 121 °C for 5 min) on integrity, uptake, and bioactivities were examined using Dicofarm, Tatua, and native bovine Lfs. Results show that pasteurization did not affect protein integrity, but variously affected uptake of Lf and its effects on intestinal proliferation, differentiation, and EPEC growth. To choose a Lf source for a clinical trial, assessment of bioactivities is recommended.

Extracellular Vesicle Activation of Latent HIV-1 Is Driven by EV-Associated c-Src and Cellular SRC-1 via the PI3K/AKT/mTOR Pathway

HIV-1 is a global health crisis that has infected more than 37 million people. Latent reservoirs throughout the body are a major hurdle when it comes to eradicating the virus. In our previous study, we found that exosomes, a type of extracellular vesicle (EV), from uninfected cells activate the transcription of HIV-1 in latent infected cells, regardless of combination antiretroviral therapy (cART). In this study, we investigated the specific mechanism behind the EV activation of latent HIV-1. We found that phosphorylated c-Src is present in EVs of various cell lines and has the ability to activate downstream proteins such as EGFR, initiating a signal cascade. EGFR is then able to activate the PI3K/AKT/mTOR pathway, resulting in the activation of STAT3 and SRC-1, culminating in the reversal of HIV-1 latency. This was verified by examining levels of HIV-1 TAR, genomic RNA and HIV-1 Gag p24 protein in cell lines and primary cells. We found that EVs containing c-Src rescued HIV-1 despite the presence of inhibitors, validating the importance of EV-associated c-Src in latent HIV-1 activation. Lastly, we discovered an increased recruitment of p300 and NF-κB in the nucleus of EV-treated infected cells. Collectively, our data suggest that EV-associated c-Src is able to activate latent HIV-1 via the PI3K/AKT/mTOR pathway and SRC-1/p300-driven chromatin remodeling. These findings could aid in designing new strategies to prevent the reactivation of latent HIV-1 in patients under cART.

Tumor-derived exosomes facilitate tumor cells escape from drug therapy in clear cell renal cell carcinoma

Background

Clear cell renal cell carcinoma (ccRCC) is one of the most prevalent cancers in renal cancer patients. Currently, mTOR and vascular endothelial growth factor (VEGF) inhibitors are the main targets of clinical drugs used to treat ccRCC. However, the major clinical challenge with these treatments is drug resistance. So far, the mechanisms of drug resistance in cancer are not fully understood.

Methods

We applied tumor-derived exosomes to treat renal cells to detect the survival rate after co-treated with anti-tumor drugs—TNFα, mammalian target of rapamycin (mTOR) inhibitor or STAT3 inhibitor. Meanwhile, we also detected the expression change in the protein level related to the proliferation and exosome secretion.

Results

Exosomes derived from renal carcinoma cells facilitate resistance in tumors cells when given drug therapy via the mTOR-ERK-STAT-NF-κB signaling pathway.

Conclusions

Our results provide new insights on tumor cells resistance to drug therapies in general, and that exosomes could be the potential targets in treatment of ccRCC in future clinical therapy.

A S100A14-CCL2/CXCL5 signaling axis drives breast cancer metastasis

Rationale: Chemokines contribute to cancer metastasis and have long been regarded as attractive therapeutic targets for cancer. However, controversy exists about whether neutralizing chemokines by antibodies promotes or inhibits tumor metastasis, suggesting that the approach to directly target chemokines needs to be scrutinized. Methods: Transwell assay, mouse metastasis experiments and survival analysis were performed to determine the functional role of S100A14 in breast cancer. RNA-Seq, secreted proteomics, ChIP, Western blot, ELISA, transwell assay and neutralizing antibody experiments were employed to investigate the underlying mechanism of S100A14 in breast cancer metastasis. Immunohistochemistry and ELISA were performed to examine the expression and serum levels of S100A14, CCL2 and CXCL5, respectively. Results: Overexpression of S100A14 significantly enhanced migration, invasion and metastasis of breast cancer cells. In contrast, knockout of S100A14 exhibited the opposite effects. Mechanistic studies demonstrated that S100A14 promotes breast cancer metastasis by upregulating the expression and secretion of CCL2 and CXCL5 via NF-κB mediated transcription. The clinical sample analyses showed that S100A14 expression is strongly associated with CCL2/CXCL5 expression and high expression of these three proteins is correlated with worse clinical outcomes. Notably, the serum levels of S100A14, CCL2/CXCL5 have significant diagnostic value for discerning breast cancer patients from healthy individuals. Conclusions: S100A14 is significantly upregulated in breast cancer, it can promote breast cancer metastasis by increasing the expression and secretion of CCL2/CXCL5 via RAGE-NF-κB pathway. And S100A14 has the potential to serve as a serological marker for diagnosis of breast cancer. Collectively, we identify S100A14 as an upstream regulator of CCL2/CXCL5 signaling and a metastatic driver of breast cancer.

Roles of S100 family members in drug resistance in tumors: Status and prospects

Chemotherapy and targeted therapy can significantly improve survival rates in cancer, but multiple drug resistance (MDR) limits the efficacy of these approaches. Understanding the molecular mechanisms underlying MDR is crucial for improving drug efficacy and clinical outcomes of patients with cancer. S100 proteins belong to a family of calcium-binding proteins and have various functions in tumor development. Increasing evidence demonstrates that the dysregulation of various S100 proteins contributes to the development of drug resistance in tumors, providing a basis for the development of predictive and prognostic biomarkers in cancer. Therefore, a combination of biological inhibitors or sensitizers of dysregulated S100 proteins could enhance therapeutic responses. In this review, we provide a detailed overview of the mechanisms by which S100 family members influence resistance of tumors to cancer treatment, with a focus on the development of effective strategies for overcoming MDR.

Do exosomes play role in cardiovascular disease development in hematological malignancy?

Exosomes play a role in the pathogenesis and treatment of malignancies as a double-edged sword. Recently, researchers discussed about two new roles, cardiomyocyte function impairment and cardiovascular disease (CVD) genesis. Data were collected from PUBMED at various time points up to the 2019 academic year. The related key words are listed as following; "Arsenic trioxide", "acute promyelocytic leukemia" and "cardio toxicity" and "molecular pathway" and "biomarker". This study has shown that exosomes secreted substances stimulate angiogenesis and cardiomyocytes repairment; cited process depended on the kinds of released substances. Generally, exosomes may involve in the pathogenesis of CVD; although CVD can prevented by identifying the pathways that induce angiogenesis.

Tumor-stroma interaction increases CD147 expression in neoplastic B lymphocytes in chronic lymphocytic leukemia

BACKGROUND

Chronic lymphocytic leukemia (CLL) microenvironment plays a critical role in disease pathogenesis. Matrix metalloproteinases (MMPs) are involved in CLL-B cell migration and survival. CD147 is associated with MMPs production by tumor and stromal cells.

AIM

To analyze CD147, MMP2 and MMP9 expression in CLL-B cells and its modulation by fibroblasts (Fb)-CLL-B cell interaction.

METHODS

CLL-B cells were co-cultured with Fb, as a simulation of CLL microenvironment. CD147 was evaluated in healthy donor (HD)-B cells and CLL-B cells by flow cytometry. MMP2 and MMP9 activity in CLL-plasma samples and conditioned media (CMs) was studied by zymography.

RESULTS

MMP9/MMP2 plasma levels were significantly higher in CLL patients than in HD. CD147 expression (median fluorescence intensity) in CLL patients characterized 3 groups: low- (19.1 ± 3.2; n=3), middle- (42.7 ± 12.8; n=18) and high- (76.5 ± 9.6; n=5) related to CD147 expression in HD-B cells. CD147 expression significantly increased in CLL-B cells after Fb-CLL-B cell co-culture. A significant increase in proMMP2 activity was observed in CMs obtained from Fb-CLL-B cell co-cultures in comparison with isolated CLL-B cells.

CONCLUSIONS

CD147 expression in CLL-B cells and MMPs secretion was induced by Fb-CLL-B cell contact, suggesting CD147 participation in the CLL pathophysiology.

Inflammatory extracellular vesicles prompt heart dysfunction via TRL4-dependent NF-κB activation

Background: After myocardial infarction, necrotic cardiomyocytes release damage-associated proteins that stimulate innate immune pathways and macrophage tissue infiltration, which drives inflammation and myocardial remodeling. Circulating inflammatory extracellular vesicles play a crucial role in the acute and chronic phases of ischemia, in terms of inflammatory progression. In this study, we hypothesize that the paracrine effect mediated by these vesicles induces direct cytotoxicity in cardiomyocytes. Thus, we examined whether reducing the generation of inflammatory vesicles within the first few hours after the ischemic event ameliorates cardiac outcome at short and long time points. Methods: Myocardial infarction was induced in rats that were previously injected intraperitoneally with a chemical inhibitor of extracellular-vesicle biogenesis. Heart global function was assessed by echocardiography performed at 7, 14 and 28 days after MI. Cardiac outcome was also evaluated by hemodynamic analysis at sacrifice. Cytotoxic effects of circulating EV were evaluated ex-vivo in a Langendorff, system by measuring the level of cardiac troponin I (cTnI) in the perfusate. Mechanisms undergoing cytotoxic effects of EV derived from pro-inflammatory macrophages (M1) were studied in-vitro in primary rat neonatal cardiomyocytes. Results: Inflammatory response following myocardial infarction dramatically increased the number of circulating extracellular vesicles carrying alarmins such as IL-1α, IL-1β and Rantes. Reducing the boost in inflammatory vesicles during the acute phase of ischemia resulted in preserved left ventricular ejection fraction in vivo. Hemodynamic analysis confirmed functional recovery by displaying higher velocity of left ventricular relaxation and improved contractility. When added to the perfusate of isolated hearts, post-infarction circulating vesicles induced significantly more cell death in adult cardiomyocytes, as assessed by cTnI release, comparing to circulating vesicles isolated from healthy (non-infarcted) rats. In vitro inflammatory extracellular vesicles induce cell death by driving nuclear translocation of NF-κB into nuclei of cardiomyocytes. Conclusion: Our data suggest that targeting circulating extracellular vesicles during the acute phase of myocardial infarction may offer an effective therapeutic approach to preserve function of ischemic heart.

Exosomes and cancer: From oncogenic roles to therapeutic applications

Exosomes belong to extracellular vehicles that were produced and secreted from most eukaryotic cells and are involved in cell-to-cell communications. They are an effective delivery system for biological compounds such as mRNAs, microRNAs (miRNAs), proteins, lipids, saccharides, and other physiological compounds to target cells. In this way, they could influence on cellular pathways and mediate their physiological behaviors including cell proliferation, tumorigenesis, differentiation, and so on. Many research studies focused on their role in cancers and also on potentially therapeutic and biomarker applications. In the current study, we reviewed the exosomes' effects on cancer progression based on their cargoes including miRNAs, long noncoding RNAs, circular RNAs, DNAs, mRNAs, proteins, and lipids. Moreover, their therapeutic roles in cancer were considered. In this regard, we have given a brief overview of challenges and obstacles in using exosomes as therapeutic agents.

S100-A9 protein in exosomes derived from follicular fluid promotes inflammation via activation of NF-κB pathway in polycystic ovary syndrome

Exosomes have recently emerged as key mediators of different physiological and pathological processes. However, there has been few report about proteomic analysis of exosomes derived from human follicular fluid and their association with the occurrence of PCOS. Herein, we used TMT‐tagged quantitative proteomic approach to identify proteomic profiles in exosomes derived from follicular fluid of PCOS patients and healthy controls. We identified 662 proteins in exosomes derived from human ovarian follicular fluid. Eighty‐six differently expressed proteins (P < .05) were found between PCOS and healthy women. The alterations in the proteomic profile were related to the inflammation process, reactive oxygen species metabolic process, cell migration and proliferation. Importantly, we observed that follicular fluid exosomes contain S100 calcium‐binding protein A9 (S100‐A9) protein. Exosome‐enriched S100‐A9 significantly enhanced inflammation and disrupted steroidogenesis via activation of nuclear factor kappa B (NF‐κB) signalling pathway. These data demonstrate that exosomal proteins are differentially expressed in follicular fluid during disease process, and some proteins may play important roles in the regulation of granulosa cell function. These results highlight the importance of exosomes as extracellular communicators in ovarian follicular development.

Keratinocyte exosomes activate neutrophils and enhance skin inflammation in psoriasis

Psoriasis is a chronic inflammatory skin disease that severely affects patients physiologically and psychologically. The pathogenesis involving communication between psoriatic keratinocytes and infiltrated immune cells such as neutrophils remains unclear. Exosomes are emerging mediators of intercellular communication. Herein we aim to investigate the release and function of psoriatic keratinocyte exosomes, which have not been illustrated to any extent. We first isolated exosomes from both healthy and psoriasis-like keratinocytes treated with psoriatic cytokine cocktail. These exosomes were observed to be endocytosed by neutrophils. Unlike non-cytokine-treated keratinocyte exosomes, cytokine-treated keratinocyte exosomes significantly induced NETosis (the process by which neutrophils produce and release neutrophil extracellular traps) and the expressions of IL-6, IL-8, and TNF-α in neutrophils. Proteomic analysis showed that cytokine-treated keratinocyte exosomes exhibited a specific protein profile with proteins enriched in immune-related pathways. We then confirmed that NF-κB and p38 MAPK signaling pathways were activated in neutrophils stimulated by cytokine-treated keratinocyte exosomes and were responsible for the expressions of proinflammatory factors mentioned above. Finally, we verified in vivo that cytokine-treated keratinocyte exosomes participated in the skin lesion development of imiquimod-induced psoriasis-like mouse model. Collectively, we reveal that the release of exosomes works as a way of keratinocyte-neutrophil communication, indicating that keratinocyte exosomes, with their specific cargoes, are therapeutic candidates for psoriasis.-Jiang, M., Fang, H., Shao, S., Dang, E., Zhang, J., Qiao, P., Yang, A., Wang, G. Keratinocyte exosomes activate neutrophils and enhance skin inflammation in psoriasis.