Pathogenic Role of Exosomes in Epstein-Barr Virus (EBV)-Associated Cancers

Peritumoral SPARC expression induced by exosomes from nasopharyngeal carcinoma infected Epstein-Barr virus: A poor prognostic marker

Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) cells have high metastatic potential. Recent research has revealed that the interaction of between tumor cells and the surrounding stroma plays an important role in tumor invasion and metastasis. In this study, we showed the prognostic value of expression of SPARC, an extracellular matrix protein with multiple cellular functions, in normal adjacent tissues (NAT) surrounding NPC. In the immunohistochemical analysis of 51 NPC biopsy specimens, SPARC expression levels were significantly elevated in the NAT of EBER (EBV-encoded small RNA)-positive NPC compared to that in the NAT of EBER-negative NPC. Moreover, increased SPARC expression in NAT was associated with a worsening of overall survival. The enrichment analysis of RNA-seq of publicly available NPC and NAT surrounding NPC data showed that high SPARC expression in NPC was associated with epithelial mesenchymal transition promotion, and there was a dynamic change in the gene expression profile associated with interference of cellular proliferation in NAT, including SPARC expression. Furthermore, EBV-positive NPC cells induce SPARC expression in normal nasopharyngeal cells via exosomes. Induction of SPARC in cancer-surrounding NAT cells reduced intercellular adhesion in normal nasopharyngeal structures and promoted cell competition between cancer cells and normal epithelial cells. These results suggest that epithelial cells loosen their own binding with the extracellular matrix as well as stromal cells, facilitating the invasion of tumor cells into the adjacent stroma by activating cell competition. Our findings reveal a new mechanism by which EBV creates a pro-metastatic microenvironment by upregulating SPARC expression in NPC.

Prokaryotic microvesicles Ortholog of eukaryotic extracellular vesicles in biomedical fields

Every single cell can communicate with other cells in a paracrine manner via the production of nano-sized extracellular vesicles. This phenomenon is conserved between prokaryotic and eukaryotic cells. In eukaryotic cells, exosomes (Exos) are the main inter-cellular bioshuttles with the potential to carry different signaling molecules. Likewise, bacteria can produce and release Exo-like particles, namely microvesicles (MVs) into the extracellular matrix. Bacterial MVs function with diverse biological properties and are at the center of attention due to their inherent therapeutic properties. Here, in this review article, the comparable biological properties between the eukaryotic Exos and bacterial MVs were highlighted in terms of biomedical application. Video Abstract.

A state-of-the-art review of the recent advances in exosome isolation and detection methods in viral infection

Proteins, RNA, DNA, lipids, and carbohydrates are only some of the molecular components found in exosomes released by tumor cells. They play an essential role in healthy and diseased cells as messengers of short- and long-distance intercellular communication. However, since exosomes are released by every kind of cell and may be found in blood and other bodily fluids, they may one day serve as biomarkers for a wide range of disorders. In many pathological conditions, including cancer, inflammation, and infection, they play a role. It has been shown that the biogenesis of exosomes is analogous to that of viruses and that the exosomal cargo plays an essential role in the propagation, dissemination, and infection of several viruses. Bidirectional modulation of the immune response is achieved by the ability of exosomes associated with viruses to facilitate immunological escape and stimulate the body's antiviral immune response. Recently, exosomes have received a lot of interest due to their potential therapeutic use as biomarkers for viral infections such as human immunodeficiency virus (HIV), Hepatitis B virus (HBV), Hepatitis C virus (HCV), Epstein-Barr virus (EBV), and SARS-CoV-2. This article discusses the purification procedures and detection techniques for exosomes and examines the research on exosomes as a biomarker of viral infection.

Engineered small extracellular vesicles as a novel platform to suppress human oncovirus-associated cancers

BACKGROUND

Cancer, as a complex, heterogeneous disease, is currently affecting millions of people worldwide. Even if the most common traditional treatments, namely, chemotherapy (CTx) and radiotherapy (RTx), have been so far effective in some conditions, there is still a dire need for novel, innovative approaches to treat types of cancer. In this context, oncoviruses are responsible for 12% of all malignancies, such as human papillomavirus (HPV), Merkel cell polyomavirus (MCPyV), Epstein-Barr virus (EBV), human herpesvirus 8 (HHV-8), as well as hepatitis B virus (HBV) and hepatitis C virus (HCV), and the poorest in the world also account for 80% of all human cancer cases. Against this background, nanomedicine has developed nano-based drug delivery systems (DDS) to meet the demand for drug delivery vectors, e.g., extracellular vesicles (EVs). This review article aimed to explore the potential of engineered small EVs (sEVs) in suppressing human oncovirus-associated cancers.

METHODS

Our search was conducted for published research between 2000 and 2022 using several international databases, including Scopus, PubMed, Web of Science, and Google Scholar. We also reviewed additional evidence from relevant published articles.

RESULTS

In this line, the findings revealed that EV engineering as a new field is witnessing the development of novel sEV-based structures, and it is expected to be advanced in the future. EVs may be further exploited in specialized applications as therapeutic or diagnostic tools. The techniques of biotechnology have been additionally utilized to create synthetic bilayers based on the physical and chemical properties of parent molecules via a top-down strategy for downsizing complicated, big particles into nano-sized sEVs.

CONCLUSION

As the final point, EV-mediated treatments are less toxic to the body than the most conventional ones, making them a safer and even more effective option. Although many in vitro studies have so far tested the efficacy of sEVs, further research is still needed to develop their potential in animal and clinical trials to reap the therapeutic benefits of this promising platform.

Extracellular vesicles from human umbilical cord mesenchymal stem cells prevent steroid-induced avascular necrosis of the femoral head via the PI3K/AKT pathway

Extracellular vesicles (EVs) secreted by human umbilical cord mesenchymal stem cells (hucMSC) have excellent therapeutic potential for many diseases. The aim of this study was to define the role of hucMSC-EVs in the prevention and treatment of steroid-induced avascular necrosis of the femoral head (SANFH). After establishing the SANFH rat model, the effects of hucMSC-EVs were assessed by measuring the microstructure of the femoral head using HE staining, micro-computed tomography (micro-CT), and TUNEL staining. The administration of hucMSC-EVs caused a significant reduction to glucocorticoids (GCs)-induced osteoblast apoptosis and empty lacuna of the femoral head, while effectively improving the microstructure. HucMSC-EVs rescued the deactivation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway induced by GCs, and reversed the proliferation and migration of osteoblasts inhibited by GCs. In addition, hucMSC-EVs attenuated the inhibitory effects of GCs on rat osteoblast osteogenesis, angiogenesis of endothelial cells, and prevented osteoblast apoptosis. However, the promoting effects of hucMSC-EVs were abolished following the blockade of PI3K/AKT on osteoblasts. hucMSC-EVs were found to prevent glucocorticoid-induced femoral head necrosis in rats through the PI3K/AKT pathway.

Extracellular Vesicles as Biomarkers in Head and Neck Squamous Cell Carcinoma: From Diagnosis to Disease-Free Survival

Head and neck squamous cell carcinomas (HNSCCs) arising from different anatomical sites present with different incidences and characteristics, which requires a personalized treatment strategy. Despite the extensive research that has conducted on this malignancy, HNSCC still has a poor overall survival rate. Many attempts have been made to improve the outcomes, but one of the bottlenecks is thought to be the lack of an effective biomarker with high sensitivity and specificity. Extracellular vesicles (EVs) are secreted by various cells and participate in a great number of intercellular communications. Based on liquid biopsy, EV detection in several biofluids, such as blood, saliva, and urine, has been applied to identify the existence and progression of a variety of cancers. In HNSCC, tumor-derived EVs exhibit many functionalities by transporting diverse cargoes, which highlights their importance in tumor screening, the determination of multidisciplinary therapy, prediction of prognosis, and evaluation of therapeutic effects. This review illustrates the classification and formation of EV subtypes, the cargoes conveyed by these vesicles, and their respective functions in HNSCC cancer biology, and discloses their potential as biomarkers during the whole process of tumor diagnosis, treatment, and follow-up.

Application of small extracellular vesicles in the diagnosis and prognosis of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant tumor originating from the epithelium of the nasopharynx. The disease is insidious, and most patients are diagnosed at the advanced stage, resulting in poor prognosis. Early diagnosis is important to reduce NPC mortality. Small extracellular vesicles (sEVs) are rich in a variety of bioactive molecules, such as proteins, nucleic acids, and lipids, which can participate in the physiological and pathological regulation of the body by affecting the function of target cells. Numerous studies have shown that some RNAs and proteins in sEVs of tumor origin have a key role in the development of NPC and are potential candidates for malignancy detection. Studying the relationship between the cargoes of these sEVs and NPC may help in the diagnosis of the disease. Here in this review, we summarize the application of sEVs as biomarkers in the diagnosis of NPC and their role in NPC metastasis and prognosis. In addition, we discuss possible future applications and limitations of sEVs as biomarkers.

Exosomal transmission of viruses, a two-edged biological sword

As a common belief, most viruses can egress from the host cells as single particles and transmit to uninfected cells. Emerging data have revealed en bloc viral transmission as lipid bilayer-cloaked particles via extracellular vesicles especially exosomes (Exo). The supporting membrane can be originated from multivesicular bodies during intra-luminal vesicle formation and autophagic response. Exo are nano-sized particles, ranging from 40-200 nm, with the ability to harbor several types of signaling molecules from donor to acceptor cells in a paracrine manner, resulting in the modulation of specific signaling reactions in target cells. The phenomenon of Exo biogenesis consists of multiple and complex biological steps with the participation of diverse constituents and molecular pathways. Due to similarities between Exo biogenesis and virus replication and the existence of shared pathways, it is thought that viruses can hijack the Exo biogenesis machinery to spread and evade immune cells. To this end, Exo can transmit complete virions (as single units or aggregates), separate viral components, and naked genetic materials. The current review article aims to scrutinize challenges and opportunities related to the exosomal delivery of viruses in terms of viral infections and public health. Video Abstract.

Role of Exosomes and Their Potential as Biomarkers in Epstein-Barr Virus-Associated Gastric Cancer

Exosomes are a subtype of extracellular vesicles ranging from 30 to 150 nm and comprising many cellular components, including DNA, RNA, proteins, and metabolites, encapsulated in a lipid bilayer. Exosomes are secreted by many cell types and play important roles in intercellular communication in cancer. Viruses can hijack the exosomal pathway to regulate viral propagation, cellular immunity, and the microenvironment. Cells infected with Epstein-Barr virus (EBV), one of the most common oncogenic viruses, have also been found to actively secrete exosomes, and studies on their roles in EBV-related malignancies are ongoing. In this review, we focus on the role of exosomes in EBV-associated gastric cancer and their clinical applicability in diagnosis and treatment.

Small extracellular vesicles as key players in cancer development caused by human oncogenic viruses

Background

Exosomes are the smallest group of extracellular vesicles in size from 30 to 150 nm, surrounded by a lipid bilayer membrane, and originate from multivesicular bodies secreted by different types of cells, such as virus-infected cells. The critical role of exosomes is information transfer among cells, representing a unique way for intercellular communication via a load of many kinds of molecules, including various signaling proteins and nucleic acids. In this review, we aimed to comprehensively investigate the role of exosomes in promoting human oncogenic viruses-associated cancers.

Methods

Our search was conducted for published researches between 2000 and 2022 by using several international databases includeing Scopus, PubMed, and Web of Science as well as Google scholar. We also reviewed additional evidence from relevant published articles.

Results

It has been shown that exosomes can create the conditions for viral spread in viral infections. Exosome secretion in a human tumor virus can switch on the cell signaling pathways by transferring exosome-encapsulated molecules, including viral oncoproteins, signal transduction molecules, and virus-encoded miRNAs, into various cells.

Conclusion

Given the role of exosomes in viruses-associated cancers, they can also be considered as molecular targets in diagnosis and treatment.

Host microRNAs are decreased in pediatric solid-organ transplant recipients during EBV+ Post-transplant Lymphoproliferative Disorder

Post-transplant lymphoproliferative disorder (PTLD) is a serious complication of solid organ transplantation. Predisposing factors include primary Epstein-Barr virus (EBV) infection, reactivation of EBV in recipient B cells, and decreased T cell immunity due to immunosuppression. In our previous studies EBV infection was demonstrated to markedly alter the expression of host B cell microRNA (miR). Specifically, miR-194 expression was uniquely suppressed in EBV+ B cell lines from PTLD patients and the 3’untranslated region of IL-10 was determined to be targeted by miR-194. Although EBV has been shown to regulate host miR expression in B cell lymphoma cell lines, the expression of miRs in the circulation of patients with EBV-associated PTLD has not been studied. The objective of this study was to determine if changes in miR expression are associated with EBV+ PTLD. In this study, we have shown that miR-194 is significantly decreased in EBV+PTLD tumors and that additional miRs, including miRs-17, 19 and 106a are also reduced in EBV+PTLD as compared to EBV-PTLD. We quantitated the levels of miRs-17, 19, 106a, 155, and 194 in the plasma and extracellular vesicles (EV; 50-70 nm as determined by nanoparticle tracking analysis) from pediatric recipients of solid organ transplants with EBV+ PTLD+ that were matched 1:2 with EBV+ PTLD- pediatric transplant recipients as part of the NIH-sponsored Clinical Trials in Organ Transplantation in Children, (CTOTC-06) study. Levels of miRs-17, 19, 106a, and 194 were reduced in the plasma and extracellular vesicles (EV) of EBV+ PTLD+ group compared to matched controls, with miRs-17 (p = 0.034; plasma), miRs-19 (p = 0.029; EV) and miR-106a (p = 0.007; plasma and EV) being significantly reduced. Similar levels of miR-155 were detected in the plasma and EV of all pediatric SOT recipients. Importantly, ~90% of the cell-free miR were contained within the EV supporting that EBV+ PTLD tumor miR are detected in the circulation and suggesting that EVs, containing miRs, may have the potential to target and regulate cells of the immune system. Further development of diagnostic, mechanistic and potential therapeutic uses of the miRs in PTLD is warranted.

FastViFi: Fast and accurate detection of (Hybrid) Viral DNA and RNA

DNA viruses are important infectious agents known to mediate a large number of human diseases, including cancer. Viral integration into the host genome and the formation of hybrid transcripts are also associated with increased pathogenicity. The high variability of viral genomes, however requires the use of sensitive ensemble hidden Markov models that add to the computational complexity, often requiring > 40 CPU-hours per sample. Here, we describe FastViFi, a fast 2-stage filtering method that reduces the computational burden. On simulated and cancer genomic data, FastViFi improved the running time by 2 orders of magnitude with comparable accuracy on challenging data sets. Recently published methods have focused on identification of location of viral integration into the human host genome using local assembly, but do not extend to RNA. To identify human viral hybrid transcripts, we additionally developed ensemble Hidden Markov Models for the Epstein Barr virus (EBV) to add to the models for Hepatitis B (HBV), Hepatitis C (HCV) viruses and the Human Papillomavirus (HPV), and used FastViFi to query RNA-seq data from Gastric cancer (EBV) and liver cancer (HBV/HCV). FastViFi ran in <10 minutes per sample and identified multiple hybrids that fuse viral and human genes suggesting new mechanisms for oncoviral pathogenicity. FastViFi is available at https://github.com/sara-javadzadeh/FastViFi.

Human Adenovirus Serotype 3 Infection Modulates the Biogenesis and Composition of Lung Cell-Derived Extracellular Vesicles

Adenovirus (Ad) is a major causal agent of acute respiratory infections. However, they are a powerful delivery system for gene therapy and vaccines. Some Ad serotypes antagonize the immune system leading to meningitis, conjunctivitis, gastroenteritis, and/or acute hemorrhagic cystitis. Studies have shown that the release of small, membrane-derived extracellular vesicles (EVs) may offer a mechanism by which viruses can enter cells via receptor-independent entry and how they influence disease pathogenesis and/or host protection considering their existence in almost all bodily fluids. We proposed that Ad3 could alter EV biogenesis, composition, and trafficking and may stimulate various immune responses in vitro. In the present study, we evaluated the impact of in vitro infection with Ad3 vector on EV biogenesis and composition in the human adenocarcinoma lung epithelial cell line A549. Cells were infected in an exosome-free media at different multiplicity of infections (MOIs) and time points. The cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and fluorometric calcein-AM. EVs were isolated via ultracentrifugation. Isolated EV proteins were quantified and evaluated via nanoparticle tracking, transmission electron microscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunoblotting assays. The cell viability significantly decreased with an increase in MOI and incubation time. A significant increase in particle mean sizes, concentrations, and total EV protein content was detected at higher MOIs when compared to uninfected cells (control group). A549 cell-derived EVs revealed the presence of TSG101, tetraspanins CD9 and CD63, and heat shock proteins 70 and 100 with significantly elevated levels of Rab5, 7, and 35 at higher MOIs (300, 750, and 1500) when compared to the controls. Our findings suggested Ad3 could modulate EV biogenesis, composition, and trafficking which could impact infection pathogenesis and disease progression. This study might suggest EVs could be diagnostic and therapeutic advancement to Ad infections and other related viral infections. However, further investigation is warranted to explore the underlying mechanism(s).

Viral Membrane Fusion Proteins and RNA Sorting Mechanisms for the Molecular Delivery by Exosomes

The advancement of precision medicine critically depends on the robustness and specificity of the carriers used for the targeted delivery of effector molecules in the human body. Numerous nanocarriers have been explored in vivo, to ensure the precise delivery of molecular cargos via tissue-specific targeting, including the endocrine part of the pancreas, thyroid, and adrenal glands. However, even after reaching the target organ, the cargo-carrying vehicle needs to enter the cell and then escape lysosomal destruction. Most artificial nanocarriers suffer from intrinsic limitations that prevent them from completing the specific delivery of the cargo. In this respect, extracellular vesicles (EVs) seem to be the natural tool for payload delivery due to their versatility and low toxicity. However, EV-mediated delivery is not selective and is usually short-ranged. By inserting the viral membrane fusion proteins into exosomes, it is possible to increase the efficiency of membrane recognition and also ease the process of membrane fusion. This review describes the molecular details of the viral-assisted interaction between the target cell and EVs. We also discuss the question of the usability of viral fusion proteins in developing extracellular vesicle-based nanocarriers with a higher efficacy of payload delivery. Finally, this review specifically highlights the role of Gag and RNA binding proteins in RNA sorting into EVs.

Exosomes in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor with a unique geographical distribution, primarily prevalent in East Africa and Asia. Although there is an increased understanding of the pathogenesis and risk factors of NPC, prevention and treatment efforts remain limited. Various studies have indicated that exosomes are actively involved in NPC by delivering biomolecules such as non-coding RNAs and proteins to target cells. In this review, we summarize the biological functions of exosomes in NPC and highlight their prospects as diagnostic biomarkers. In NPC, exosomes can manipulate the tumor microenvironment, participate in chemotherapy and radiation resistance, induce immune suppression, promote pathological angiogenesis, and support metastasis, and thus they could also be promising biomarkers. Because exosomes have essential effects and unusual biological properties, they have a promising future in diagnostic monitoring and prognostic evaluation. Although there are technical issues associated with using exosomes in large-scale applications, they have unparalleled advantages in assisting the clinical management of NPC.

Epstein-Barr Virus-Associated Malignancies and Immune Escape: The Role of the Tumor Microenvironment and Tumor Cell Evasion Strategies

Simple Summary

The Epstein–Barr virus, also termed human herpes virus 4, is a human pathogenic double-stranded DNA virus. It is highly prevalent and has been linked to the development of 1–2% of cancers worldwide. EBV-associated malignancies encompass various structural and epigenetic alterations. In addition, EBV-encoded gene products and microRNAs interfere with innate and adaptive immunity and modulate the tumor microenvironment. This review provides an overview of the characteristic features of EBV with a focus on the intrinsic and extrinsic immune evasion strategies, which contribute to EBV-associated malignancies.

Abstract

The detailed mechanisms of Epstein–Barr virus (EBV) infection in the initiation and progression of EBV-associated malignancies are not yet completely understood. During the last years, new insights into the mechanisms of malignant transformation of EBV-infected cells including somatic mutations and epigenetic modifications, their impact on the microenvironment and resulting unique immune signatures related to immune system functional status and immune escape strategies have been reported. In this context, there exists increasing evidence that EBV-infected tumor cells can influence the tumor microenvironment to their own benefit by establishing an immune-suppressive surrounding. The identified mechanisms include EBV gene integration and latent expression of EBV-infection-triggered cytokines by tumor and/or bystander cells, e.g., cancer-associated fibroblasts with effects on the composition and spatial distribution of the immune cell subpopulations next to the infected cells, stroma constituents and extracellular vesicles. This review summarizes (i) the typical stages of the viral life cycle and EBV-associated transformation, (ii) strategies to detect EBV genome and activity and to differentiate various latency types, (iii) the role of the tumor microenvironment in EBV-associated malignancies, (iv) the different immune escape mechanisms and (v) their clinical relevance. This gained information will enhance the development of therapies against EBV-mediated diseases to improve patient outcome.

Multiplex protein profiling method for extracellular vesicle protein detection

Extracellular vesicles (EVs) are small nanometer-sized membrane sacs secreted into biological fluids by all cells. EVs encapsulate proteins, RNAs and metabolites from its origin cell and play important roles in intercellular communication events. Over the past decade, EVs have become a new emerging source for cancer diagnostics. One of the challenges in the study of EVs and there utility as diagnostic biomarkers is the amount of EVs needed for traditional protein analysis methods. Here, we present a new immuno-PCR method that takes advantage of commercially available TotalSeq antibodies containing DNA conjugated oligos to identify immobilized protein analysts using real-time qPCR. Using this method, we demonstrate that multiple EV surface proteins can be profiled simultaneously with high sensitivity and specificity. This approach was also successfully applied to similar protocol using cell and serum samples. We further described the development of a micro-size exclusion chromatography method, where we were able to detect EV surface proteins with as little as 10 μL of human serum when combined with immuno-PCR. Overall, these results show that the immuno-PCR method results in rapid detection of multiple EV markers from small sample volumes in a single tube.

The role of Exosomes in the Pathogenesis of Nasopharyngeal Carcinoma and the involved Clinical Application

Exosomes are nanoscale membrane vesicles, which carry biologically active substances of their cell of origin and play an important role in signal transduction and intercellular communication. At present, exosomes have been identified as a promising non-invasive liquid biopsy biomarker in the tissues and circulating blood of nasopharyngeal carcinoma (NPC) and found to participate in regulating pathophysiological process of the tumor. We here review recent insights gained into the molecular mechanisms of exosome-induced cell growth, angiogenesis, metastasis, immunosuppression, radiation resistance and chemotherapy resistance in the development and progression of NPC, as well as the clinical application of exosomes as diagnostic biomarkers and therapeutic agents. We also discuss the limitations and challenges in exosome application. We hope this review may provide some references for the use of exosomes in clinical intervention.

Exosomes From Subjects With Multiple Sclerosis Express EBV-Derived Proteins and Activate Monocyte-Derived Macrophages

Objective

To investigate in a cross-sectional study the effect of serum-derived exosomes on primary human blood monocyte-derived macrophages (MDMs) comparing exosomes from healthy donors vs patients with relapsing-remitting multiple sclerosis in remission and in relapse and to assess whether the response correlates with exosomal Epstein-Barr virus (EBV) protein expression.

Methods

A total of 45 serum-derived exosome preparations were isolated from patients and healthy controls and verified for the expression of exosomal and EBV markers. MDMs were differentiated from monocytes for 7 days and incubated for 24 hours with exosomes, and then, cell supernatants were collected for cytokine measurement by cytometric bead array. Cells were immunophenotyped before and after differentiation.

Results

Serum-derived exosomes of patients with multiple sclerosis (MS) expressed higher levels of EBV proteins than healthy controls. Of interest, expression of EBV nuclear antigen EBNA1 and latent membrane proteins LMP1 and 2A was higher on exosomes derived from patients with active RRMS compared with healthy controls and stable patients. After data normalization, we observed that incubation with EBV(+) exosomes induced CXCL10 and CCL2 secretion by MDMs. MDMs differentiated from patients with active disease were better secretors of CXCL10 and other interferon-γ–inducible chemokines, including CCL2 and CXCL9, than MDMs from healthy and stable MS groups. MDMs from active patients had a higher frequency of a CD14(++) subset that correlated with the secreted CXCL10.

Conclusion

Exosomes expressing EBV proteins correlate with disease activity and induce an inflammatory response in MDMs that is compounded by the origin of the responder cells.

Designer Exosomes: A New Platform for Biotechnology Therapeutics

Abstract

Desirable features of exosomes have made them a suitable manipulative platform for biomedical applications, including targeted drug delivery, gene therapy, cancer diagnosis and therapy, development of vaccines, and tissue regeneration. Although natural exosomes have various potentials, their clinical application is associated with some inherent limitations. Recently, these limitations inspired various attempts to engineer exosomes and develop designer exosomes. Mostly, designer exosomes are being developed to overcome the natural limitations of exosomes for targeted delivery of drugs and functional molecules to wounds, neurons, and the cardiovascular system for healing of damage. In this review, we summarize the possible improvements of natural exosomes by means of two main approaches: parental cell-based or pre-isolation exosome engineering and direct or post-isolation exosome engineering. Parental cell-based engineering methods use genetic engineering for loading of therapeutic molecules into the lumen or displaying them on the surface of exosomes. On the other hand, the post-isolation exosome engineering approach uses several chemical and mechanical methods including click chemistry, cloaking, bio-conjugation, sonication, extrusion, and electroporation. This review focuses on the latest research, mostly aimed at the development of designer exosomes using parental cell-based engineering and their application in cancer treatment and regenerative medicine.

Graphic Abstract

Proteomic and phospholipidomic characterization of extracellular vesicles inducing tumor microenvironment in Epstein-Barr virus-associated lymphomas

Epstein-Barr virus (EBV) causes malignant carcinomas including B cell lymphomas accompanied by the systemic inflammation. Previously, we observed that phosphatidylserine (PS)-exposing subset of extracellular vesicles (EVs) secreted from an EBV strain Akata-transformed lymphoma (Akata EVs) convert surrounding phagocytes into tumor-associated macrophages (TAMs) via induction of inflammatory response, which is in part mediated by EBV-derived micro RNAs. However, it is still unclear about EV-carried other potential inflammatory factors associated with TAM formation in EBV lymphomas. To this end, we sought to explore proteomic and phospholipidomic profiles of PS-exposing EVs derived from EBV-transformed lymphomas. Mass spectrometric analysis revealed that several immunomodulatory proteins including integrin αLβ2 and fibroblast growth factor 2 (FGF2) were highly expressed in PS-exposing Akata EVs compared with another EBV strain B95-8-transformed lymphoma-derived counterparts which significantly lack TAM-inducing ability. Pharmacological inhibition of either integrin αLβ2 or FGF2 hampered cytokine induction in monocytic cultured cells elicited by PS-exposing Akata EVs, suggesting the involvement of these proteins in EV-mediated TAM induction in EBV lymphomas. In addition, phospholipids containing precursors of immunomodulatory lipid mediators were also enriched in PS-exposing Akata EVs compared with B95-8 counterparts. Phospholipidomic analysis of fractionated Akata EVs by density gradient centrifugation further demonstrated that PS-exposing Akata EVs might be identical to certain Akata EVs in low density fractions containing exosomes. Therefore, we concluded that a variety of immunomodulatory cargo molecules in a certain EV subtype are presumably conducive to the development of EBV lymphomas.

Extracellular vesicles in cancer nanomedicine

To date, a lot of nanotechnological optitions are available for targeted drug delivery. Extracellular vesicles (EVs) are membrane structures that cells use for storage, transport, communication, and signaling. Recent research has focused on EVs as natural nanoparticles for drug delivery. This review sheds light on the application of EVs in cancer therapy, such as targeted chemotherapy, gene therapy, and vaccine development. Aspects of biogenesis, isolation, targeting, and loading of EVs are discussed in detail.

Long Non-coding RNAs in Gammaherpesvirus Infections: Their Roles in Tumorigenic Mechanisms

Long non-coding RNAs (lncRNAs) regulate gene expression at the epigenetic, transcriptional, or posttranscriptional level by interacting with protein, DNA, and RNA. Emerging evidence suggests that various lncRNAs are abnormally expressed and play indispensable roles in virus-triggered cancers. Besides, a growing number of studies have shown that virus-encoded lncRNAs participate in tumorigenesis. However, the functions of most lncRNAs in tumors caused by oncogenic viruses and their underlying mechanisms remain largely unknown. In this review, we summarize current findings regarding lncRNAs involved in cancers caused by Epstein–Barr virus (EBV) and Kaposi’s sarcoma herpesvirus (KSHV). Additionally, we discuss the contribution of lncRNAs to tumor occurrence, development, invasion, and metastasis; the roles of lncRNAs in key signaling pathways and their potential as biomarkers and therapeutic targets for tumor diagnostics and treatment.

Novel Therapies Boosting T Cell Immunity in Epstein Barr Virus-Associated Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant tumour of the head and neck affecting localised regions of the world, with the highest rates described in Southeast Asia, Northern Africa, and Greenland. Its high morbidity rate is linked to both late-stage diagnosis and unresponsiveness to conventional anti-cancer treatments. Multiple aetiological factors have been described including environmental factors, genetics, and viral factors (Epstein Barr Virus, EBV), making NPC treatment that much more complex. The most common forms of NPCs are those that originate from the epithelial tissue lining the nasopharynx and are often linked to EBV infection. Indeed, they represent 75–95% of NPCs in the low-risk populations and almost 100% of NPCs in high-risk populations. Although conventional surgery has been improved with nasopharyngectomy’s being carried out using more sophisticated surgical equipment for better tumour resection, recent findings in the tumour microenvironment have led to novel treatment options including immunotherapies and photodynamic therapy, able to target the tumour and improve the immune system. This review provides an update on the disease’s aetiology and the future of NPC treatments with a focus on therapies activating T cell immunity.

Recent Advances in Diagnostic Approaches for Epstein-Barr Virus

Epstein-Barr virus (EBV) is the causative agent of many diseases including infectious mononucleosis (IM), and it is associated with different subtypes of lymphoma, sarcoma and carcinoma such as Hodgkin's lymphoma, non-Hodgkin's lymphoma, nasopharyngeal carcinoma, and gastric carcinoma. With the advent of improved laboratory tests for EBV, a timelier and accurate diagnosis could be made to aid better prognosis and effective treatment. For histopathological lesions, the in situ hybridization (ISH) of EBV-encoded RNA (EBER) in biopsy tissues remains the gold standard for detecting EBV. Methods such as the heterophile antibody test, immunofluorescence assays, enzyme immunoassays, Western blot, and polymerase chain reaction (PCR) are also employed in the detection of EBV in different types of samples. The determination of EBV viral load using PCR, however, is gaining more prominence in the diagnosis of EBV-associated diseases. Given the challenge of false positive/negative results that are sometimes experienced during the detection of EBV, variability in results from different laboratories, and the impact of factors such as sample type and the immunological status of patients from whom samples are collected, the need to critically examine these present methods is invaluable. This review thus presents current advances in the detection of EBV, detailing the advantages and disadvantages of the various techniques. In addition, fundamental virological concepts are highlighted to enhance the greater understanding, the proper application, and the interpretation of EBV tests.

Epstein barr virus encodes miRNAs to assist host immune escape

Epstein-barr virus (EBV) is a definite tumorigenic virus, which can form life-long latency in the host, which is difficult to be recognized and completely eliminated by the immune system. It is closely related to the occurrence and development of nasopharyngeal cancer, gastric cancer and various types of lymphoma. At present, a total of 44 Epstein-barr virus-encoded microRNAs (EBV miRNAs) have been found. In response to the immune system of the body, EBV miRNAs can inhibit the expression and presentation of viral antigens, inhibit immune activation and immunotoxicity, assisting host cells to escape from immunity, and providing conditions for further immortalized tumorigenesis of the host cells.

The role of Epstein-Barr virus infection in primary Sjögren's syndrome

PURPOSE OF REVIEW

The purpose of this article is to draw attention to the role of Epstein-Barr virus (EBV) virus in the pathogenesis of the primary Sjögren's syndrome. The article introduces the problem of consequences of EBV acute infection, and its reactivation, in association with the immune response modulation by the virus and with an increased risk of developing systemic autoimmune diseases and EBV-associated cancers.

RECENT FINDINGS

The knowledge about the mechanisms by which the virus may stay for years in a latent phase, unrecognized by the host response immune cells is constantly expanding. There are several mechanisms and theories about EBV influence on the autoimmune process in Sjogren's syndrome (pSS), including the similarity (molecular mimicry) between viral EBNA-2 protein and Ro-60 antigen or EBER-1 and EBER-2 viral proteins and La antigen.

SUMMARY

The influence of EBV infection on the development and course of pSS has been proven. It has also been established that both EBV and pSS result in the increased risk of tumor (especially lymphoma) development. In the light of these findings, new ways to manage EBV infections are being sought. Optimal methods for assessing EBV infection status are being devised. Research also aims at finding therapies, which target EBV through the inhibition of the autoimmune process and of viral activity. The present article is an attempt to discuss the most important phenomena and elements linking EBV infection to the primary Sjögren's syndrome.

The Function and Therapeutic Potential of Epstein-Barr Virus-Encoded MicroRNAs in Cancer

Epstein-Barr virus (EBV) is a ubiquitous human γ-herpesvirus that infects over 90% of the global population. EBV is considered a contributory factor in a variety of malignancies including nasopharyngeal carcinoma, gastric carcinoma, Burkitt lymphoma, and Hodgkin’s lymphoma. Notably, EBV was the first virus found to encode microRNAs (miRNAs). Increasing evidence indicates that EBV-encoded miRNAs contribute to the carcinogenesis and development of EBV-associated malignancies. EBV miRNAs have been shown to inhibit the expression of genes involved in cell proliferation, apoptosis, invasion, and immune signaling pathways. Therefore, EBV miRNAs perform a significant function in the complex host-virus interaction and EBV-driven carcinogenesis. However, the integrated mechanisms underlying the roles of EBV miRNAs in carcinogenesis remain to be further explored. In this review, we describe recent advances regarding the involvement of EBV miRNAs in the pathogenesis of EBV-associated malignancies and discuss their potential utility as cancer biomarkers. An in-depth investigation into the pro-carcinogenic role of EBV miRNAs will expand our knowledge of the biological processes associated with virus-driven tumors and contribute to the development of novel therapeutic strategies for the treatment of EBV-associated malignancies.

Radiation therapy-induced reactive oxygen species specifically eliminates CD19+IgA+ B cells in nasopharyngeal carcinoma

Purpose

Nasopharyngeal carcinoma (NPC) is one of the most common head and neck cancers and is thought to be related to the mucosal immune system. Radiation therapy (RT) is the primary treatment for NPC due to the high radiosensitivity of cancer cells. However, little is known about the impact of RT on the mucosal immune system.

Patients and methods

In this study, the expression of immune markers CD19, CD24, CD27, CD8, and IgA before and after RT, were analyzed using flow cytometry. Cytokines were assessed using the enzyme-linked immunosorbent assay. Reactive oxygen species (ROS) was assayed by flow cytometry and fluorescence staining using 2ʹ,7ʹ -dichlorofluorescein diacetate.

Results

We found that primary NPC patients had a significant increase in CD19⁺CD138⁻IgA⁺ B cells, which was then decreased after RT. Interestingly, the changes in CD19⁺CD138⁻IgA⁺ B cell frequency was accompanied by corresponding frequency changes in cytotoxic T cells (CTL), which are powerful anti-tumor lymphocytes. Mechanistically, we found that ROS release during RT specifically eliminated CD19⁺CD138⁻IgA⁺ B cells.

Conclusion

These findings suggest that RT may regulate the immune system and opens up new avenues for the utilization of immune-radiotherapy in NPC.

Key Gaps in the Knowledge of the Porcine Respiratory Reproductive Syndrome Virus (PRRSV)

The porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important swine diseases in the world. It is causing an enormous economic burden due to reproductive failure in sows and a complex respiratory syndrome in pigs of all ages, with mortality varying from 2 to 100% in the most extreme cases of emergent highly pathogenic strains. PRRSV displays complex interactions with the immune system and a high mutation rate, making the development, and implementation of control strategies a major challenge. In this review, the biology of the virus will be addressed focusing on newly discovered functions of non-structural proteins and novel dissemination mechanisms. Secondly, the role of different cell types and viral proteins will be reviewed in natural and vaccine-induced immune response together with the role of different immune evasion mechanisms focusing on those gaps of knowledge that are critical to generate more efficacious vaccines. Finally, novel strategies for antigen discovery and vaccine development will be discussed, in particular the use of exosomes (extracellular vesicles of endocytic origin). As nanocarriers of lipids, proteins and nucleic acids, exosomes have potential effects on cell activation, modulation of immune responses and antigen presentation. Thus, representing a novel vaccination approach against this devastating disease.

Ras and exosome signaling

Ras gene (HRAS, NRAS, and KRAS) has been observed to be mutated and hyper-activated in a significant proportion of cancers. However, mutant Ras remains a challenging therapeutic target. Similarly, inhibition of targets upstream and downstream of Ras has shown limited clinical utility. There have been attempts to develop and deliver mutant K-Ras silencing RNAs either through their encapsulation in liposomes or nanoparticles. However, these approaches show very limited success due to the lack of stability of such carrier molecules alongside associated toxicity. There is a pressing need for the identification of better therapeutic targets for Ras or its associated pathways as well as improvements in the design of superior RNAi delivery systems to suppress mutant K-Ras. More than a decade ago, it was shown that aggregates of palmitoylated Ras isoforms (H-Ras and N-Ras) passage through the cytosol on rapidly moving nanosized particles ("rasosomes"). Fast forward a decade, considerable new knowledge has emerged in the area of small vesicles, microparticles, and exosomes. Exosomes are tiny vesicles and play a significant role in regulating cancer-related signaling pathways. Exosomes have also been studied as delivery vehicles to transport drugs, proteins, and microRNAs of choice for therapeutic purposes. K-Ras pathway proteins have been implicated in exosome biogenesis and extravasation processes. This review provides an update on the current knowledge related to K-Ras signaling and exosomes and also discusses how these tiny vesicles can be harnessed to successfully deliver the K-Ras silencing moieties.

Modulation of radiation sensitivity and antitumor immunity by viral pathogenic factors: Implications for radio-immunotherapy

Several DNA viruses including Human Papillomavirus (HPV), Epstein-Barr virus (EBV), and Human cytomegalovirus (HCMV) are mechanistically associated with the development of human cancers (HPV, EBV) and/or modulation of the immune system (HCMV). Moreover, a number of distinct mechanisms have been described regarding the modulation of tumor cell response to ionizing radiation and evasion from the host immune system by viral factors. There is further accumulating interest in the treatment with immune-modulatory therapies such as immune checkpoint inhibitors for malignancies with a viral etiology. Also, patients with HPV-positive tumors have a significantly improved prognosis that is attributable to increased intrinsic radiation sensitivity and may also arise from modulation of a cytotoxic T cell response in the tumor microenvironment (TME). In this review, we will highlight recent advances in the understanding of the biological basis of radiation response mediated by viral pathogenic factors and evasion from and modulation of the immune system by viruses.

Exosomes in virus-associated cancer

Exosomes are phospholipid bilayer membrane-enclosed vesicles in a size from 30 to 150 nm, carrying a variety of active components, such as proteins, mRNA and miRNAs, and are involved in intercellular communication. Exosomes are released by almost all living cells and detected in various biological fluids. Viruses especially oncogenic viruses have been reported to influence the formation of virus-associated cancer through reshaping the tumor microenvironment via exosomes. In this review, a role of exosomes released by oncogenic virus-infected cells in promoting or inhibiting cancer formation is outlined. Moreover, the prospects and challenges of exosome applications in cancer therapies are critically discussed.

Pathobiologic Roles of Epstein-Barr Virus-Encoded MicroRNAs in Human Lymphomas

Epstein-Barr virus (EBV) is a human γ-herpesvirus implicated in several human malignancies, including a wide range of lymphomas. Several molecules encoded by EBV in its latent state are believed to be related to EBV-induced lymphomagenesis, among which microRNAs-small RNAs with a posttranscriptional regulating role-are of great importance. The genome of EBV encodes 44 mature microRNAs belonging to two different classes, including BamHI-A rightward transcript (BART) and Bam HI fragment H rightward open reading frame 1 (BHRF1), with different expression levels in different EBV latency types. These microRNAs might contribute to the pathogenetic effects exerted by EBV through targeting self mRNAs and host mRNAs and interfering with several important cellular mechanisms such as immunosurveillance, cell proliferation, and apoptosis. In addition, EBV microRNAs can regulate the surrounding microenvironment of the infected cells through exosomal transportation. Moreover, these small molecules could be potentially used as molecular markers. In this review, we try to present an updated and extensive view of the role of EBV-encoded miRNAs in human lymphomas.

Epstein-Barr Virus as a Promising Immunotherapeutic Target for Nasopharyngeal Carcinoma Treatment

Epstein-Barr virus (EBV) is a pathogen that infects more than 90% of global human population. EBV primarily targets B-lymphocytes and epithelial cells while some of them infect monocyte/macrophage, T-lymphocytes, and dendritic cells (DCs). EBV infection does not cause death by itself but the infection has been persistently associated with certain type of cancers such as nasopharyngeal carcinoma (NPC), Burkitt's lymphoma (BL), and Hodgkin's lymphoma (HL). Recent findings have shown promise on targeting EBV proteins for cancer therapy by immunotherapeutic approach. Some studies have also shown the success of adopting EBV-based therapeutic vaccines for the prevention of EBV-associated cancer particularly on NPC. In-depth investigations are in progress to refine the current therapeutic and vaccination strategies. In present review, we discuss the highly potential EBV targets for NPC immunotherapy and therapeutic vaccine development as well as addressing the underlying challenges in the process of bringing the therapy and vaccination from the bench to bedside.