Nasopharyngeal Carcinoma: An Evolving Role for the Epstein-Barr Virus

Pathogenesis and therapeutic implications of EBV-associated epithelial cancers

Epstein-Barr virus (EBV), one of the most common human viruses, has been associated with both lymphoid and epithelial cancers. Undifferentiated nasopharyngeal carcinoma (NPC), EBV associated gastric cancer (EBVaGC) and lymphoepithelioma-like carcinoma (LELC) are amongst the few common epithelial cancers that EBV has been associated with. The pathogenesis of EBV-associated NPC has been well described, however, the same cannot be said for primary pulmonary LELC (PPLELC) owing to the rarity of the cancer. In this review, we outline the pathogenesis of EBV-associated NPC and EBVaGCs and their recent advances. By drawing on similarities between NPC and PPLELC, we then also postulated the pathogenesis of PPLELC. A deeper understanding about the pathogenesis of EBV enables us to postulate the pathogenesis of other EBV associated cancers such as PPLELC.

Neoantigens and their clinical applications in human gastrointestinal cancers

Background

Tumor-specific neoantigens are ideal targets for cancer immunotherapy. As research findings have proved, neoantigen-specific T cell activity is immunotherapy’s most important determinant.

Main text

There is sufficient evidence showing the role of neoantigens in clinically successful immunotherapy, providing a justification for targeting. Because of the significance of the pre-existing anti-tumor immune response for the immune checkpoint inhibitor, it is believed that personalized neoantigen-based therapy may be an imperative approach for cancer therapy. Thus, intensive attention is given to strategies targeting neoantigens for the significant impact with other immunotherapies, such as the immune checkpoint inhibitor. Today, several algorithms are designed and optimized based on Next-Generation Sequencing and public databases, including dbPepNeo, TANTIGEN 2.0, Cancer Antigenic Peptide Database, NEPdb, and CEDAR databases for predicting neoantigens in silico that stimulates the development of T cell therapies, cancer vaccine, and other ongoing immunotherapy approaches.

Conclusions

In this review, we deliberated the current developments in understanding and recognition of the immunogenicity of newly found gastrointestinal neoantigens as well as their functions in immunotherapies and cancer detection. We also described how neoantigens are being developed and how they might be used in the treatment of GI malignancies.

Integration Profiling Between Plasma Lipidomics, Epstein–Barr Virus and Clinical Phenomes in Nasopharyngeal Carcinoma Patients

Plasma lipidomics has been commonly used for biomarker discovery. Studies in cancer have suggested a significant alteration of circulating metabolite profiles which is correlated with cancer characteristics and treatment outcome. However, the lipidomics characteristics of nasopharyngeal carcinoma (NPC) have rarely been studied. We previously described the phenomenon of lipid droplet accumulation in NPC cells and showed that such accumulation could be regulated by latent infection of Epstein–Barr virus (EBV). Here, we compared the plasma lipidome of NPC patients to that of healthy controls by liquid chromatography-tandem mass spectrometry (LC–MS/MS). We found 19 lipids (e.g., phosphatidylinositols 18:0/20:4 and 18:0/18:2 and free fatty acid 22:6) to be remarkably decreased, whereas 2 lipids (i.e., diacylglycerols 16:0/16:1 and 16:0/20:3) to be increased, in the plasma of NPC patients, compared with controls. Different lipid profiles were also observed between patients with different titers of EBV antibodies (e.g., EA-IgA and VCA-IgA) as well as between patients with and without lymph node or distant organ metastasis. In conclusion, plasma lipidomics might help to differentiate NPC cases from controls, whereas EBV infection might influence the risk and prognosis of NPC through modulating lipid metabolism in both tumor cells and peripheral blood.

Major Role for Cellular MicroRNAs, Long Noncoding RNAs (lncRNAs), and the Epstein-Barr Virus-Encoded BART lncRNA during Tumor Growth In Vivo

This study assessed the effects of Epstein-Barr virus (EBV) and one form of virally encoded BART long noncoding RNAs (lncRNAs) on cellular expression in epithelial cells grown in vitro and as tumors in vivo determined by high-throughput RNA sequencing of mRNA and small RNAs. Hierarchical clustering based on gene expression distinguished the cell lines from the tumors and distinguished the EBV-positive tumors and the BART tumors from the EBV-negative tumors. EBV and BART expression also induced specific expression changes in cellular microRNAs (miRs) and lncRNAs. Multiple known and predicted targets of the viral miRs, the induced cellular miRs, and lncRNAs were identified in the altered gene set. The changes in expression in vivo indicated that the suppression of growth pathways in vivo reflects increased expression of cellular miRs in all tumors. In the EBV and BART tumors, many of the targets of the induced miRs were not changed and the seed sequences of the nonfunctional miRs were found to have homologous regions within the BART lncRNA. The inhibition of these miR effects on known targets suggests that these induced miRs have reduced function due to sponging by the BART lncRNA. This composite analysis identified the effects of EBV on cellular miRs and lncRNAs with a functional readout through identification of the simultaneous effects on gene expression. Major shifts in gene expression in vivo are likely mediated by effects on cellular noncoding RNAs. Additionally, a predicted property of the BART lncRNA is to functionally inhibit the induced cellular miRs.

Prognostic Epstein-Barr Virus (EBV) miRNA biomarkers for survival outcome in EBV-associated epithelial malignancies: Systematic review and meta-analysis

Background

The EBV-associated epithelial tumours consist 80% of all EBV-associated cancer, where the nasopharyngeal cancer (NPC) and EBV-associated gastric carcinoma (EBVaGC) are considered as the most frequent EBV-associated epithelial tumours. It has been shown that the BART-encoded miRNAs are abundantly expressed in EBV-associated epithelial tumours, hence, these miRNAs may serve as diagnostic and prognostic biomarkers for EBV-associated epithelial tumours. Therefore, the purpose of this systematic review and meta-analysis is to assess these EBV miRNAs as prognostic biomarkers for NPC and GC.

Method

This systematic review was developed based on PRISMA guidelines and utilizing PubMed, Web of Science, Scopus, Cochrane, and Google scholar databases. The retrieved articles were thoroughly screened in accordance with the selection criteria. The hazard ratio (HR) and 95% confidence interval (CI) for patient survival outcomes were used to evaluate EBV miRNA expression levels. To assess the risk of bias, funnel plot symmetry and Egger’s bias test were employed.

Result

Eleven studies met the selection criteria for inclusion, and four were included in the meta-analysis. Most of the articles considered in this study were from China, with one study from South Korea. The overall pooled effect size estimation (HR) for upregulated EBV miRNAs was 3.168 (95% CI: 2.020–4.969), demonstrating that upregulated EBV miRNA expression enhanced the mortality risk in NPC and GC patients by three times.

Conclusion

To the best of our knowledge, this is the first meta-analysis that investigates the significance of EBV miRNAs as prognostic biomarkers in NPC and GC patients. The pooled effect estimates of HR of the various studies revealed that higher EBV miRNA expression in NPC and GC may result in a worse survival outcome. To assess the clinical significance of EBV miRNAs as prognostic biomarkers, larger-scale prospective studies are needed.

Interaction sites of the Epstein-Barr virus Zta transcription factor with the host genome in epithelial cells

Epstein-Barr virus (EBV) is present in a state of latency in infected memory B-cells and EBV-associated lymphoid and epithelial cancers. Cell stimulation or differentiation of infected B-cells and epithelial cells induces reactivation to the lytic replication cycle. In each cell type, the EBV transcription and replication factor Zta (BZLF1, EB1) plays a role in mediating the lytic cycle of EBV. Zta is a transcription factor that interacts directly with Zta response elements (ZREs) within viral and cellular genomes. Here we undertake chromatin-precipitation coupled to DNA-sequencing (ChIP-Seq) of Zta-associated DNA from cancer-derived epithelial cells. The analysis identified over 14 000 Zta-binding sites in the cellular genome. We assessed the impact of lytic cycle reactivation on changes in gene expression for a panel of Zta-associated cellular genes. Finally, we compared the Zta-binding sites identified in this study with those previously identified in B-cells and reveal substantial conservation in genes associated with Zta-binding sites.

Epstein Barr Virus: Development of Vaccines and Immune Cell Therapy for EBV-Associated Diseases

Epstein-Barr virus (EBV) is the first human tumor virus discovered and is strongly implicated in the etiology of multiple lymphoid and epithelial cancers. Each year EBV associated cancers account for over 200,000 new cases of cancer and cause 150,000 deaths world-wide. EBV is also the primary cause of infectious mononucleosis, and up to 70% of adolescents and young adults in developed countries suffer from infectious mononucleosis. In addition, EBV has been shown to play a critical role in the pathogenesis of multiple sclerosis. An EBV prophylactic vaccine that induces neutralizing antibodies holds great promise for prevention of EBV associated diseases. EBV envelope proteins including gH/gL, gB and gp350 play key roles in EBV entry and infection of target cells, and neutralizing antibodies elicited by each of these proteins have shown to prevent EBV infection of target cells and markedly decrease EBV titers in the peripheral blood of humanized mice challenged with lethal dose EBV. Recent studies demonstrated that immunization with the combination of gH/gL, gB and/or gp350 induced markedly increased synergistic EBV neutralizing activity compared to immunization with individual proteins. As previous clinical trials focused on gp350 alone were partially successful, the inclusion of gH/gL and gB in a vaccine formulation with gp350 represents a promising approach of EBV prophylactic vaccine development. Therapeutic EBV vaccines have also been tested clinically with encouraging results. Immunization with various vaccine platforms expressing the EBV latent proteins EBNA1, LMP1, and/or LMP2 promoted specific CD4+ and CD8+ cytotoxic responses with anti-tumor activity. The addition of EBV envelope proteins gH/gL, gB and gp350 has the potential to increase the efficacy of a therapeutic EBV vaccine. The immune system plays a critical role in the control of tumors, and immune cell therapy has emerged as a promising treatment of cancers. Adoptive T-cell therapy has been successfully used in the prevention and treatment of post-transplant lymphoproliferative disorder. Chimeric antigen receptor T cell therapy and T cell receptor engineered T cell therapy targeting EBV latent proteins LMP1, LMP2 and/or EBNA1 have been in development, with the goal to increase the specificity and efficacy of treatment of EBV associated cancers.

Thymic Lymphoepithelial Carcinoma Associated with Epstein-Barr Virus: Experiences and Literature Review

Thymic lymphoepithelial carcinoma (TLEC) is a primary thymic carcinoma that accounts for about 14% of all thymic epithelial tumors and is classified into 14 types. The histological morphology is similar to lymphoepithelioma, a type of undifferentiated nasopharyngeal carcinoma. It has been reported that squamous carcinoma accounts for approximately 80% of thymic carcinoma, followed by TLEC, which accounts for 6%. TLEC has been reported to be associated with Epstein-Barr virus (EBV), with EBV infection in TLEC tumor cells first noted by Lyvraz et al. in 1985. Tumors shown to be EBV-positive are classified as TLEC if lymphoplasmacytic infiltration is lacking. However, only about 50% of the cases are positive for EBV, which is lower compared to nasopharyngeal lymphoepithelioma. Instances of EBV infection in other types of thymic epithelial tumor have been reported at lower rates, which suggests that EBV infection may have an important influence on the carcinogenesis of TLEC, though the etiology is unknown. TLEC is a highly malignant tumor with poor prognosis, as affected patients have a median survival time of 22 months, according to 58 cases from the literature, while the 5-year survival rate is 34.4%. Presently, prognosis is not considered to be affected by the presence or absence of EBV positivity.

Epstein-Barr virus nuclear antigen-1 is useful as therapeutic efficacy marker in serum but not in saliva of nasopharyngeal cancer patients who underwent radiotherapy

Introduction

Nasopharyngeal carcinoma (NPC) is a multifactorial disease with genetic, viral, environmental and lifestyle-related risk factors. Epstein–Barr virus (EBV) can promote the oncogenic transformation of an infected cell into malignant. EBV encodes many stimulating products including Epstein–Barr virus nuclear antigen-1 (EBNA-1) which plays a key role in the regulation of gene expression and replication of the genome in the latent period of infection. EBNA-1 in serum and tumour tissue of NPC patients correlates with NPC prognosis. Moreover, the presence of EBV DNA in serum samples from NPC patients’ blood circulation can be used as an early marker in the diagnosis of NPC.

Objective

The objective of this study was to find effective methods for monitoring the progress of NPC patients undergoing radiotherapy and therapeutic efficacy by observing the changes in EBV DNA in serum and saliva.

Methodology

The pre-experimental design compared blood and saliva taken from a pre-test and post-test group of NPC patients before and after radiation therapy. The concentration of EBV DNA was measured in the serum and saliva after amplification using quantitative polymerase chain reaction (qPCR) with compatible primers for the EBNA-1 gene. The data were statistically analysed by paired T-test.

Results

Highly significant (p = 0.0001) increase in cycle threshold qPCR and decrease in the mean concentration of EBV DNA (p = 0.0001) were observed in serum samples, but no significant changes were observed in saliva.

Conclusions

The results suggest that EBV DNA in serum can be used as the gold standard and a marker for monitoring the response to radiation therapy in NPC patients, whereas the examination of EBV DNA from saliva samples is not accurate and thus, not appropriate.

Advances in research on microRNAs related to the invasion and metastasis of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC), which is associated with latent Epstein-Barr virus infection in most cases, is a unique epithelial malignancy arising from the nasopharyngeal mucosal lining. Accumulating evidence provides insights into the genetic and molecular aberrations that likely drive nasopharyngeal tumor development and progression. We review recent analyses of microRNAs (miRNAs), including Epstein-Barr virus-encoded miRNAs (EBV-encoded miRNAs) and dysregulated cellular miRNAs, that may be related to the metastasis of nasopharyngeal carcinoma. The studies summarized herein have greatly expanded our knowledge of the molecular biology of NPC involving miRNAs, and they may provide new biological targets for clinical diagnosis and reveal the potential of microRNA therapeutics. However, much information remains to be uncovered.

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.

A primary nasopharyngeal three-dimensional air-liquid interface cell culture model of the pseudostratified epithelium reveals differential donor- and cell type-specific susceptibility to Epstein-Barr virus infection

Epstein-Barr virus (EBV) is a ubiquitous γ-herpesvirus with latent and lytic cycles. EBV replicates in the stratified epithelium but the nasopharynx is also composed of pseudostratified epithelium with distinct cell types. Latent infection is associated with nasopharyngeal carcinoma (NPC). Here, we show with nasopharyngeal conditionally reprogrammed cells cultured at the air-liquid interface that pseudostratified epithelial cells are susceptible to EBV infection. Donors varied in susceptibility to de novo EBV infection, but susceptible cultures also displayed differences with respect to pathogenesis. The cultures from one donor yielded lytic infection but cells from two other donors were positive for EBV-encoded EBERs and negative for other lytic infection markers. All cultures stained positive for the pseudostratified markers CK7, MUC5AC, α-tubulin in cilia, and the EBV epithelial cell receptor Ephrin receptor A2. To define EBV transcriptional programs by cell type and to elucidate latent/lytic infection-differential changes, we performed single cell RNA-sequencing on one EBV-infected culture that resulted in alignment with many EBV transcripts. EBV transcripts represented a small portion of the total transcriptome (~0.17%). All cell types in the pseudostratified epithelium had detectable EBV transcripts with suprabasal cells showing the highest number of reads aligning to many EBV genes. Several restriction factors (IRF1, MX1, STAT1, C18orf25) known to limit lytic infection were expressed at lower levels in the lytic subcluster. A third of the differentially-expressed genes in NPC tumors compared to an uninfected pseudostratified ALI culture overlapped with the differentially-expressed genes in the latent subcluster. A third of these commonly perturbed genes were specific to EBV infection and changed in the same direction. Collectively, these findings suggest that the pseudostratified epithelium could harbor EBV infection and that the pseudostratified infection model mirrors many of the transcriptional changes imposed by EBV infection in NPC.

It has been known for over 50 years that EBV infection is associated with NPC. Despite many advances from studies in 2-dimensional cell culture, many aspects of EBV molecular pathogenesis in the nasopharynx remain undefined because the cell types and the biology of the nasopharyngeal epithelium can only be faithfully captured in 3-dimensional cell culture. In the stratified epithelium, cellular differentiation triggers lytic infection but it is not clear to what degree the pseudostratified epithelium is involved. The pseudostratified epithelium is abundant in the lateral wall where the lymphoid-rich fossa of Rosenmüller is located and is a site where NPC tumors most often arises. While the oral epithelium is a site of EBV replication, whether the nasopharyngeal epithelium is a major source of EBV shedding in the nasopharynx is not well defined. Here, we present a 3-dimensional organoid model of the nasopharyngeal pseudostratified epithelium showing that such cells can be infected with EBV in some donor cultures, with examples of both latent and lytic infection. We propose that the cell types of the pseudostratified epithelium should be considered a component of EBV pathogenesis in the nasopharynx and that the difference in donor susceptibility and latent/lytic infection could influence EBV’s fitness in the nasopharynx.

Epstein-Barr Virus Limits the Accumulation of IPO7, an Essential Gene Product

Epstein-Barr virus (EBV) encodes more than 40 miRNAs that target cellular mRNAs to aid its infection, replication, and maintenance in individual cells and in its human host. Importin-7 (IPO7), also termed Imp7 or RanBPM7, is a nucleocytoplasmic transport protein that has been frequently identified as a target for two of these viral miRNAs. How the viral life cycle might benefit from regulating IPO7 has been unclear, though. We demonstrate with CRISPR-Cas9 mutagenesis that IPO7 is essential in at least three cells lines and that increasing its levels of expression inhibits growth of infected cells. EBV thus regulates the level of IPO7 to limit its accumulation consistent with its being required for survival of its host cell.

Somatostatin receptor 2 expression in nasopharyngeal cancer is induced by Epstein Barr virus infection: impact on prognosis, imaging and therapy

Nasopharyngeal cancer (NPC), endemic in Southeast Asia, lacks effective diagnostic and therapeutic strategies. Even in high-income countries the 5-year survival rate for stage IV NPC is less than 40%. Here we report high somatostatin receptor 2 (SSTR2) expression in multiple clinical cohorts comprising 402 primary, locally recurrent and metastatic NPCs. We show that SSTR2 expression is induced by the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) via the NF-κB pathway. Using cell-based and preclinical rodent models, we demonstrate the therapeutic potential of SSTR2 targeting using a cytotoxic drug conjugate, PEN-221, which is found to be superior to FDA-approved SSTR2-binding cytostatic agents. Furthermore, we reveal significant correlation of SSTR expression with increased rates of survival and report in vivo uptake of the SSTR2-binding 68Ga-DOTA-peptide radioconjugate in PET-CT scanning in a clinical trial of NPC patients (NCT03670342). These findings reveal a key role in EBV-associated NPC for SSTR2 in infection, imaging, targeted therapy and survival.

HNSCC: Tumour Antigens and Their Targeting by Immunotherapy

Head and neck squamous cell carcinomas (HNSCC) are a heterogeneous group of malignant tumours typically caused by alcohol and tobacco consumption, although an increasing number of HNSCC arise due to persistent infection with high-risk human papilloma virus (HPV). The treatment of HNSCC remains challenging, and the first-line setting is focused on surgery and chemoradiotherapy. A substantial proportion of HNSCC patients die from their disease, especially those with recurrent and metastatic disease. Among factors linked with good outcome, immune cell infiltration appears to have a major role. HPV-driven HNSCC are often T-cell rich, reflecting the presence of HPV antigens that are immunogenic. Tumour-associated antigens that are shared between patients or that are unique to an individual person may also induce varying degrees of immune response; studying these is important for the understanding of the interaction between the host immune system and the cancer. The resulting knowledge is critical for the design of better immunotherapies. Key questions are: Which antigens lead to an adaptive immune response in the tumour? Which of these are exploitable for immunotherapy? Here, we review the current thinking regarding tumour antigens in HNSCC and what has been learned from early phase clinical trials.

Targeting Epstein-Barr Virus in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is consistently associated with Epstein-Barr virus (EBV) infection in regions in which it is endemic, including Southern China and Southeast Asia. The high mortality rates of NPC patients with advanced and recurrent disease highlight the urgent need for effective treatments. While recent genomic studies have revealed few druggable targets, the unique interaction between the EBV infection and host cells in NPC strongly implies that targeting EBV may be an efficient approach to cure this virus-associated cancer. Key features of EBV-associated NPC are the persistence of an episomal EBV genome and the requirement for multiple viral latent gene products to enable malignant transformation. Many translational studies have been conducted to exploit these unique features to develop pharmaceutical agents and therapeutic strategies that target EBV latent proteins and induce lytic reactivation in NPC. In particular, inhibitors of the EBV latent protein EBNA1 have been intensively explored, because of this protein's essential roles in maintaining EBV latency and viral genome replication in NPC cells. In addition, recent advances in chemical bioengineering are driving the development of therapeutic agents targeting the critical functional regions of EBNA1. Promising therapeutic effects of the resulting EBNA1-specific inhibitors have been shown in EBV-positive NPC tumors. The efficacy of multiple classes of EBV lytic inducers for NPC cytolytic therapy has also been long investigated. However, the lytic-induction efficiency of these compounds varies among different EBV-positive NPC models in a cell-context-dependent manner. In each tumor, NPC cells can evolve and acquire somatic changes to maintain EBV latency during cancer progression. Unfortunately, the poor understanding of the cellular mechanisms regulating EBV latency-to-lytic switching in NPC cells limits the clinical application of EBV cytolytic treatment. In this review, we discuss the potential approaches for improvement of the above-mentioned EBV-targeting strategies.

Circulating Epstein-Barr virus microRNAs BART7-3p and BART13-3p as novel biomarkers in nasopharyngeal carcinoma

Epstein‐Barr virus (EBV) BamHI A rightward transcripts (BART) encoded microRNAs (EBV‐miR‐BARTs) are abnormally highly expressed in nasopharyngeal carcinoma (NPC). This study aims to investigate the diagnostic and prognostic performance of miR‐BART7‐3p and miR‐BART13‐3p. Plasma levels of EBV DNA, miR‐BART7‐3p, and miR‐BART13‐3p were examined by quantitative PCR in 483 treatment‐naïve NPC patients and 243 controls without NPC. The prognostic performance was examined by comparing plasma levels with rates of distant metastasis during follow‐up. The area under the receiver operating characteristic curve for diagnosing NPC was 0.926 for EBV DNA, 0.964 for plasma miR‐BART7‐3p, 0.973 for miR‐BART13‐3p, and 0.997 for all three indices. Among 465 NPC patients without distant metastasis, the above‐median miR‐BART7‐3p and EBV DNA were independent risk for shorter distant metastasis‐free survival (DMFS) (hazard ratio [HR] = 2.94, 95% confidence interval [CI], 1.44‐5.97, P = .003; HR = 2.27, 95% CI, 1.26‐4.10, P = .006) in multivariate Cox regression. Epstein‐Barr virus DNA, miR‐BART7‐3p, and miR‐BART13‐3p after radiotherapy were detectable in 28.6%, 17.6%, and 54.7% of patients, respectively. In multivariate Cox regression, detectable miR‐BART7‐3p and EBV DNA were independent risks for shorter DMFS (HR = 4.13, 95% CI, 1.89‐9.01, P < .001; HR = 2.14, 95% CI, 1.04‐4.42, P = .039). The 4‐year DMFS rate was 92.0% in subjects (n = 156) with neither detectable miR‐BART7‐3p nor EBV DNA, 80.0% in subjects (n = 65) with either detectable miR‐BART7‐3p or EBV DNA, and 52.9% in subjects (n = 24) with both detectable miR‐BART7‐3p and EBV DNA after radiotherapy (P < .001). Circulating levels of miR‐BART7‐3p and miR‐BART13‐3p show excellent diagnostic performance for NPC. The combination of plasma levels of miR‐BART7‐3p and EBV DNA at diagnosis and after radiotherapy could help stratify patients by risk of poor DMFS.

Identification of a 7-microRNA signature in plasma as promising biomarker for nasopharyngeal carcinoma detection

Background

Circulating microRNAs (miRNAs) have become reliable sources of non‐invasive biomarkers for cancer diagnosis. Identification of promising miRNA biomarkers in plasma might benefit a lot to the detection of nasopharyngeal carcinoma (NPC).

Methods

The Exiqon miRNA qPCR panel was used in the screening stage to identify candidate miRNAs, which were further verified by quantitative reverse transcription polymerase chain reaction (qRT‐PCR) in the following three stages among plasma samples from 200 NPC patients and 189 healthy donors (as normal controls [NCs]). The identified miRNAs were further explored in tissue specimens (48 NPC vs 32 NCs) and plasma exosomes (32 NPC vs 32 NCs). Survival analyses were ultimately conducted by Cox regression models and Kaplan‐Meier curves using log‐rank tests.

Results

We identified a 7‐miRNA signature including let‐7b‐5p, miR‐140‐3p, miR‐144‐3p, miR‐17‐5p, miR‐20a‐5p, miR‐20b‐5p, and miR‐205‐5p in plasma for NPC diagnosis after four‐stage validation. The areas under the receiver operating characteristic curve (AUCs) for the signature were 0.879, 0.884, 0.921, and 0.807 for the training, testing, external validation stage, and the combined three stages, respectively. In NPC tissues, miR‐144‐3p, miR‐17‐5p, miR‐20a‐5p, and miR‐205‐5p were consistently up‐regulated while let‐7b‐5p and miR‐140‐3p were significantly down‐regulated compared to NCs. However, none of the seven identified miRNAs were dysregulated in plasma‐derived exosomes in NPC patients. As to survival analysis, none of the seven miRNAs seemed to be associated with NPC prognosis.

Conclusion

We identified a 7‐miRNA signature in plasma as promising non‐invasive biomarkers for NPC detection.

Total thymectomy for thymic lymphoepithelioma-like carcinoma-report of two cases

Background

Thymic carcinoma has been classified into 12 subtypes, thymic lymphoepithelioma-like carcinoma (LELC) is a type of them, and has a pathological organization similar to that of lymphoepithelioma, an undifferentiated type of nasopharyngeal carcinoma. According to a report from the International Thymic Malignancy Interest Group (ITMIG), thymic LELC is a rare tumor and accounts for 6% of all thymic carcinoma cases. We report two cases of surgical resection for thymic LELC and perform a search of other reports of thymic LELC, and clinical manifestations and follow-up data thus obtained are summarized.

Case presentation

Two patients underwent surgical resection for thymic LELC. In both, tumors were detected in the anterior mediastinum and a total thymectomy was performed. Each was diagnosed with thymic LELC and classified in accordance with the Masaoka staging system as modified stage II. In recent examinations, one patient was doing well after undergoing total resection, whereas early recurrence of distant lymph node metastasis was noted in the other at 5 months after the total resection procedure and died thereafter from a different disease.

Conclusion

We report two cases of surgical resection for thymic LELC. A successful total resection may positively affect prognosis: thus, long-term follow-up examinations must be performed.

Alterations in cellular expression in EBV infected epithelial cell lines and tumors

The Epstein Barr virus (EBV) is linked to the development of two major epithelial malignancies, gastric carcinoma and nasopharyngeal carcinoma. This study evaluates the effects of EBV on cellular expression in a gastric epithelial cell line infected with or without EBV and a nasopharyngeal carcinoma cell line containing EBV. The cells were grown in vitro and as tumors in vivo. The effects on cellular expression were determined using both 2D DIGE proteomics and high throughput RNA sequencing. The data identify multiple pathways that were uniquely activated in vitro. RNA sequences mapping to the mouse genome were identified in both the EBV positive and negative tumor samples in vivo, although, differences between the EBV positive and negative cells were not apparent. However, the tumors appeared to be grossly distinct. The majority of the identified canonical pathways based on two fold changes in expression had decreased activity within the tumors in vivo. Identification of the predicted upstream regulating factors revealed that in vitro the regulating factors were primarily protein transcriptional regulators. In contrast, in vivo the predicted regulators were frequently noncoding RNAs. Hierarchical clustering distinguished the cell lines and tumors, the EBV positive tumors from the EBV negative tumors, and the NPC tumors from the gastric tumors and cell lines. The delineating genes were changed greater than 4 fold and were frequently regulated by protein transcription factors. These data suggest that EBV distinctly affects cellular expression in gastric tumors and NPC and that growth in vivo requires activation of fewer cellular signaling pathways. It is likely that the broad changes in cellular expression that occur at low levels are controlled by regulatory viral and cellular RNAs while major changes are affected by induced protein regulators.

The Glypican-4 Gene Polymorphism rs1048369 and Susceptibility to Epstein-Barr Virus-Positive and -Negative Nasopharyngeal Carcinoma in Northern China

BACKGROUND

Gene polymorphism rs1048369 of glypican-4 (GPC4) gene has been reported to be significantly different between Epstein-Barr virus (EBV)-associated gastric carcinoma (GC) and EBV-negative GC. However, little is known about the polymorphism in nasopharyngeal carcinoma (NPC), which is a malignant tumor with a high prevalence of EBV.

OBJECTIVE

The distribution of GPC4 polymorphism rs1048369 was investigated in NPC patients, especially in those with EBV infection. The association between the polymorphism of GPC4 and the susceptibility to EBV-positive and EBV-negative NPC was also explored.

PATIENTS AND METHODS

The GPC4 gene polymorphism rs1048369 was detected in 143 cases of EBV-positive NPC and in 19 cases of EBV-negative NPC using polymerase chain reaction. One hundred and seven peripheral blood samples from healthy individuals were also measured as a control group.

RESULTS

The difference in genotype CC between EBV-positive NPC patients and healthy individuals was significant (χ2 = 15.273, p < 0.01). No significant difference was observed between EBV-positive and EBV-negative NPC cases. Between EBV-negative NPC cases and healthy individuals, there was no significant difference in GPC4 gene polymorphism in both genotypic and allelic frequencies.

CONCLUSIONS

The GPC4 gene polymorphism is associated with susceptibility to EBV-positive NPC. The CC genotype of GPC4 may represent a risk factor for NPC in Northern China.

The Global Landscape of EBV-Associated Tumors

Epstein-Barr virus (EBV), a gamma-1 herpesvirus, is carried as a life-long asymptomatic infection by the great majority of individuals in all human populations. Yet this seemingly innocent virus is aetiologically linked to two pre-malignant lymphoproliferative diseases (LPDs) and up to nine distinct human tumors; collectively these have a huge global impact, being responsible for some 200,000 new cases of cancer arising worldwide each year. EBV replicates in oral epithelium but persists as a latent infection within the B cell system and several of its diseases are indeed of B cell origin; these include B-LPD of the immunocompromised, Hodgkin Lymphoma (HL), Burkitt Lymphoma (BL), Diffuse Large B cell Lymphoma (DLBCL) and two rarer tumors associated with profound immune impairment, plasmablastic lymphoma (PBL) and primary effusion lymphoma (PEL). Surprisingly, the virus is also linked to tumors arising in other cellular niches which, rather than being essential reservoirs of virus persistence in vivo, appear to represent rare cul-de-sacs of latent infection. These non-B cell tumors include LPDs and malignant lymphomas of T or NK cells, nasopharyngeal carcinoma (NPC) and gastric carcinoma of epithelial origin, and leiomyosarcoma, a rare smooth muscle cell tumor of the immunocompromised. Here we describe the main characteristics of these tumors, their distinct epidemiologies, histological features and degrees of EBV association, then consider how their different patterns of EBV latency may reflect the alternative latency programmes through which the virus first colonizes and then persists in immunocompetent host. For each tumor, we discuss current understanding of EBV's role in the oncogenic process, the identity (where known) of host genetic and environmental factors predisposing tumor development, and the recent evidence from cancer genomics identifying somatic changes that either complement or in some cases replace the contribution of the virus. Thereafter we look for possible connections between the pathogenesis of these apparently different malignancies and point to new research areas where insights may be gained.

Genome-wide CRISPR-based gene knockout screens reveal cellular factors and pathways essential for nasopharyngeal carcinoma

Early diagnosis of nasopharyngeal carcinoma (NPC) is difficult because of a lack of specific symptoms. Many patients have advanced disease at diagnosis, and these patients respond poorly to treatment. New treatments are therefore needed to improve the outcome of NPC. To better understand the molecular pathogenesis of NPC, here we used an NPC cell line in a genome-wide CRISPR-based knockout screen to identify the cellular factors and pathways essential for NPC (i.e. dependence factors). This screen identified the Moz, Ybf2/Sas3, Sas2, Tip60 histone acetyl transferase complex, NF-κB signaling, purine synthesis, and linear ubiquitination pathways; and MDM2 proto-oncogene as NPC dependence factors/pathways. Using gene knock out, complementary DNA rescue, and inhibitor assays, we found that perturbation of these pathways greatly reduces the growth of NPC cell lines but does not affect growth of SV40-immortalized normal nasopharyngeal epithelial cells. These results suggest that targeting these pathways/proteins may hold promise for achieving better treatment of patients with NPC.

Exosomal cyclophilin A as a novel noninvasive biomarker for Epstein-Barr virus associated nasopharyngeal carcinoma

Exosomes have emerged as novel vehicles for proteins and other contents in cancer progression. Cyclophilin A (CYPA) is a pivotal member of immunophilin family. Whether CYPA can be detected in sera of nasopharyngeal carcinoma (NPC) patients remains to be explored. Epstein-Barr virus (EBV) is the first identified human tumor virus and is a causative agent of NPC. The antibody of EBV capsid antigen immunoglobulin A (EBV-VCA-IgA) is a known biomarker of NPC, with a proportion of no more than 70% being detected positively. Hence, novel biomarkers need to be discovered for early diagnosis, prognosis, and monitoring of EBV-associated NPC. A total of 110 NPC and 36 normal control serum samples were collected. Exosomes from these samples were extracted. The mRNA and protein expression levels of the above samples were validated by reverse transcription -quantitative polymerase chain reaction, Western blotting, or enzyme-linked immunosorbent assay (ELISA). Finally, the results demonstrated that both the serum and exosomal CYPA levels of NPC patients were significantly higher than that of normal cases. In addition, exosomal CYPA had a much higher level than that in the whole sera. The positive rate of EBV-VCA-IgA antibody was 68.2% in NPC sera, and noticeably, among the cases with EBV-VCA-IgA negative, 80% of them presented high levels of CYPA above the standard (cutoff value). In particular, CYPA in exosomes was uniformly with higher significance than that in whole sera. Combined analysis of CYPA protein and EBV-VCA-IgA antibody showed a greatly higher discriminatory ability in diagnosis of NPC. Moreover, exosomal CYPA level had a positive correlation with that of the EBV-encoded latent membrane protein 1 (LMP1) in exosomes. EBV-positive cancer cells secreted significantly higher levels of exosomal CYPA. This study established the utility of circulating exosomal CYPA as a potential noninvasive diagnostic biomarker for EBV-associated NPC.

Epstein-Barr Virus-Positive Cancers Show Altered B-Cell Clonality

Around 20% of human cancers are associated with viruses. Epstein-Barr virus (EBV) contributes to gastric cancer, nasopharyngeal carcinoma, and certain lymphomas, but its role in other cancer types remains controversial. We assessed the prevalence of EBV in RNA-seq from 32 tumor types in the Cancer Genome Atlas Project (TCGA) and found EBV to be present in >5% of samples in 12 tumor types. EBV infects epithelial cells and B cells and in B cells causes proliferation. We hypothesized that the low expression of EBV in most of the tumor types was due to infiltration of B cells into the tumor. The increase in B-cell abundance and diversity in subjects where EBV was detected in the tumors strengthens this hypothesis. Overall, we found that EBV was associated with an increased and altered immune response. This result is not evidence of causality, but a potential novel biomarker for tumor immune status.

Epstein-Barr virus (EBV) is convincingly associated with gastric cancer, nasopharyngeal carcinoma, and certain lymphomas, but its role in other cancer types remains controversial. To test the hypothesis that there are additional cancer types with high prevalence of EBV, we determined EBV viral expression in all the Cancer Genome Atlas Project (TCGA) mRNA sequencing (mRNA-seq) samples (n = 10,396) from 32 different tumor types. We found that EBV was present in gastric adenocarcinoma and lymphoma, as expected, and was also present in >5% of samples in 10 additional tumor types. For most samples, EBV transcript levels were low, which suggests that EBV was likely present due to infected infiltrating B cells. In order to determine if there was a difference in the B-cell populations, we assembled B-cell receptors for each sample and found B-cell receptor abundance (P ≤ 1.4 × 10⁻²⁰) and diversity (P ≤ 8.3 × 10⁻²⁷) were significantly higher in EBV-positive samples. Moreover, diversity was independent of B-cell abundance, suggesting that the presence of EBV was associated with an increased and altered B-cell population.

IMPORTANCE Around 20% of human cancers are associated with viruses. Epstein-Barr virus (EBV) contributes to gastric cancer, nasopharyngeal carcinoma, and certain lymphomas, but its role in other cancer types remains controversial. We assessed the prevalence of EBV in RNA-seq from 32 tumor types in the Cancer Genome Atlas Project (TCGA) and found EBV to be present in >5% of samples in 12 tumor types. EBV infects epithelial cells and B cells and in B cells causes proliferation. We hypothesized that the low expression of EBV in most of the tumor types was due to infiltration of B cells into the tumor. The increase in B-cell abundance and diversity in subjects where EBV was detected in the tumors strengthens this hypothesis. Overall, we found that EBV was associated with an increased and altered immune response. This result is not evidence of causality, but a potential novel biomarker for tumor immune status.

Air-Liquid Interface System To Understand Epstein-Barr Virus-Associated Nasopharyngeal Carcinoma

Epstein-Barr virus (EBV) infects epithelial cells and is associated with epithelial malignancies. Although EBV reactivation is induced by epithelial differentiation, the available methods for differentiation are not widely used.

Epstein-Barr virus (EBV) infects epithelial cells and is associated with epithelial malignancies. Although EBV reactivation is induced by epithelial differentiation, the available methods for differentiation are not widely used. In a recent study, Caves et al. (mSphere 3:e00152-18, 2018, https://doi.org/10.1128/mSphere.00152-18) explored the use of a new transwell-based air-liquid interface (ALI) system to differentiate EBV-infected nasopharyngeal carcinoma cells. They found that cells cultured in the ALI system expressed markers of differentiation and supported complete EBV reactivation. This system offers an easy method for differentiation that could be widely adopted. This system could be extended to other epithelial cell types.

Air-Liquid Interface Method To Study Epstein-Barr Virus Pathogenesis in Nasopharyngeal Epithelial Cells

Epstein-Barr virus (EBV) is a ubiquitous gammaherpesvirus that establishes a latent reservoir in peripheral B-lymphocytes with sporadic reactivation. EBV also infects epithelial cells, predominantly resulting in a lytic infection, which may contribute to EBV transmission from saliva. In the nasopharynx, EBV infection can lead to the clonal expansion of a latently infected cell and the development of nasopharyngeal carcinoma (NPC). The mechanisms governing EBV pathogenesis in nasopharyngeal epithelium are largely unknown. An advanced understanding would depend on a physiologically relevant culture model of polarized airway epithelium. The recent application of the organotypic raft culture in keratinocytes has demonstrated great promise for the use of polarized cultures in the study of EBV permissive replication. In this study, the adaptation of an air-liquid interface (ALI) culture method using transwell membranes was explored in an EBV-infected NPC cell line. In the EBV-infected NPC HK1 cell line, ALI culture resulted in the completion of EBV reactivation, with global induction of the lytic cascade, replication of EBV genomes, and production of infectious progeny virus. We propose that the ALI culture method can be widely adopted as a physiologically relevant model to study EBV pathogenesis in polarized nasal epithelial cells.

IMPORTANCE

Lifting adherent cells to the air-liquid interface (ALI) is a method conventionally used to culture airway epithelial cells into polarized apical and basolateral surfaces. Reactivation of Epstein-Barr virus (EBV) from monolayer epithelial cultures is sometimes abortive, which may be attributed to the lack of authentic reactivation triggers that occur in stratified epithelium in vivo In the present work, the ALI culture method was applied to study EBV reactivation in nasopharyngeal epithelial cells. The ALI culture of an EBV-infected cell line yielded high titers and can be dissected by a variety of molecular virology assays that measure induction of the EBV lytic cascade and EBV genome replication and assembly. EBV infection of polarized cultures of primary epithelial cells can be challenging and can have variable efficiencies. However, the use of the ALI method with established EBV-infected cell lines offers a readily available and reproducible approach for the study of EBV permissive replication in polarized epithelia.

Serum long non-coding RNAs MALAT1, AFAP1-AS1 and AL359062 as diagnostic and prognostic biomarkers for nasopharyngeal carcinoma

Circulating RNAs in serum, plasma or other body liquid have emerged as useful and highly promising biomarkers for noninvasive diagnostic application. Herein, we aimed to establish a serum long non-coding RNAs (lncRNAs) signature for diagnosing nasopharyngeal carcinoma (NPC). In this study, we recruited a cohort of 101 NPC patients, 20 patients with chronic nasopharyngitis (CN), 20 EBV carriers (EC) and 101 healthy controls. qRT-PCR was performed with NPC cells and serum samples to screen a pool of 38 NPC-related lncRNAs obtained from the LncRNADisease database. A profile of three circulating lncRNAs (MALAT1, AFAP1-AS1 and AL359062) was established for NPC diagnosis. By Receiver Operating Characteristic (ROC) curve analysis, this three-lncRNA signature showed high accuracy in discriminating NPC from healthy controls (AUC = 0.918), CN (AUC = 0.893) or EC (AUC = 0.877). Furthermore, high levels of these three lncRNAs were closely related to advanced NPC tumor node metastasis stages and EBV infection. Serum levels of these three lncRNAs declined significantly in patients after therapy. Our present study indicates that circulating MALAT1, AFAP1-AS1 and AL359062 may represent novel serum biomarkers for NPC diagnosis and prognostic prediction after treatment.

Tumour viruses and innate immunity

Host cells sense viral infection through pattern recognition receptors (PRRs), which detect pathogen-associated molecular patterns (PAMPs) and stimulate an innate immune response. PRRs are localized to several different cellular compartments and are stimulated by viral proteins and nucleic acids. PRR activation initiates signal transduction events that ultimately result in an inflammatory response. Human tumour viruses, which include Kaposi's sarcoma-associated herpesvirus, Epstein-Barr virus, human papillomavirus, hepatitis C virus, hepatitis B virus, human T-cell lymphotropic virus type 1 and Merkel cell polyomavirus, are detected by several different PRRs. These viruses engage in a variety of mechanisms to evade the innate immune response, including downregulating PRRs, inhibiting PRR signalling, and disrupting the activation of transcription factors critical for mediating the inflammatory response, among others. This review will describe tumour virus PAMPs and the PRRs responsible for detecting viral infection, PRR signalling pathways, and the mechanisms by which tumour viruses evade the host innate immune system.This article is part of the themed issue 'Human oncogenic viruses'.

Epstein-Barr virus infection and nasopharyngeal carcinoma

Epstein-Barr virus (EBV) is associated with multiple types of human cancer, including lymphoid and epithelial cancers. The closest association with EBV infection is seen in undifferentiated nasopharyngeal carcinoma (NPC), which is endemic in the southern Chinese population. A strong association between NPC risk and the HLA locus at chromosome 6p has been identified, indicating a link between the presentation of EBV antigens to host immune cells and NPC risk. EBV infection in NPC is clonal in origin, strongly suggesting that NPC develops from the clonal expansion of a single EBV-infected cell. In epithelial cells, the default program of EBV infection is lytic replication. However, latent infection is the predominant mode of EBV infection in NPC. The establishment of latent EBV infection in pre-invasive nasopharyngeal epithelium is believed to be an early stage of NPC pathogenesis. Recent genomic study of NPC has identified multiple somatic mutations in the upstream negative regulators of NF-κB signalling. Dysregulated NF-κB signalling may contribute to the establishment of latent EBV infection in NPC. Stable EBV infection and the expression of latent EBV genes are postulated to drive the transformation of pre-invasive nasopharyngeal epithelial cells to cancer cells through multiple pathways.This article is part of the themed issue 'Human oncogenic viruses'.

Decreased macrophage inflammatory protein (MIP)-1α and MIP-1β increase the risk of developing nasopharyngeal carcinoma

Background

The association of circulating inflammation markers with nasopharyngeal carcinoma (NPC) is still largely unclear. This study aimed to comprehensively explore the relationship between circulating cytokine levels and the subsequent risk of NPC with a two-stage epidemiologic study in southern China.

Methods

The serum levels of 33 inflammatory cytokines were first measured in a hospital-based case–control study (150 NPC patients and 150 controls) using multiplex assay platforms. Marker levels were categorized into two or more groups based on the proportion of sample measurements that was above the lower limit of detection. Odds ratios (ORs) and 95% confidence intervals (CIs) relating the serum marker concentration to the risk of NPC were computed by multivariable logistic regression models. The associations were validated in 60 patients with NPC and 120 controls in a subsequent nested case–control study within a NPC screening trial. Potential interactions between serum cytokines and Epstein–Barr virus (EBV) relating to the risk of NPC were assessed using a likelihood ratio test.

Results

The levels of serum macrophage inflammatory protein (MIP)-1α and MIP-1β in the highest categories were associated with a decreased risk of NPC in both the case–control study (MIP-1α: OR = 0.49, 95% CI = 0.26–0.95; MIP-1β: OR = 0.47, 95% CI = 0.22–1.00) and the nested case–control study (MIP-1α: OR = 0.13, 95% CI = 0.03–0.62; MIP-1β: OR = 0.20, 95% CI = 0.04–0.94), compared with those in the lowest categories. Furthermore, individuals with lower levels of these two cytokine markers who were EBV seropositive presented with a largely higher risk of NPC compared with patients with higher levels who were EBV seronegative in both the case–control study (MIP-1α: OR = 16.28, 95% CI = 7.11–37.23; MIP-1β: OR = 12.86, 95% CI = 5.9–28.05) and the nested case–control study (MIP-1α: OR = 86.12, 95% CI = 10.58–701.03; MIP-1β: OR = 115.44, 95% CI = 13.92–957.73).

Conclusions

Decreased preclinical MIP-1α and MIP-1β levels might be associated with a subsequently increased risk of NPC. More mechanistic studies are required to fully understand this finding.

Electronic supplementary material

The online version of this article (10.1186/s40880-018-0279-y) contains supplementary material, which is available to authorized users.

EBV-encoded miRNAs target ATM-mediated response in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a highly invasive epithelial malignancy that is prevalent in southern China and Southeast Asia. It is consistently associated with latent Epstein-Barr virus (EBV) infection. In NPC, miR-BARTs, the EBV-encoded miRNAs derived from BamH1-A rightward transcripts, are abundantly expressed and contribute to cancer development by targeting various cellular and viral genes. In this study, we establish a comprehensive transcriptional profile of EBV-encoded miRNAs in a panel of NPC patient-derived xenografts and an EBV-positive NPC cell line by small RNA sequencing. Among the 40 miR-BARTs, predominant expression of 22 miRNAs was consistently detected in these tumors. Among the abundantly expressed EBV-miRNAs, BART5-5p, BART7-3p, BART9-3p, and BART14-3p could negatively regulate the expression of a key DNA double-strand break (DSB) repair gene, ataxia telangiectasia mutated (ATM), by binding to multiple sites on its 3'-UTR. Notably, the expression of these four miR-BARTs represented more than 10% of all EBV-encoded miRNAs in tumor cells, while downregulation of ATM expression was commonly detected in all of our tested sequenced samples. In addition, downregulation of ATM was also observed in primary NPC tissues in both qRT-PCR (16 NP and 45 NPC cases) and immunohistochemical staining (35 NP and 46 NPC cases) analysis. Modulation of ATM expression by BART5-5p, BART7-3p, BART9-3p, and BART14-3p was demonstrated in the transient transfection assays. These findings suggest that EBV uses miRNA machinery as a key mechanism to control the ATM signaling pathway in NPC cells. By suppressing these endogenous miR-BARTs in EBV-positive NPC cells, we further demonstrated the novel function of miR-BARTs in inhibiting Zta-induced lytic reactivation. These findings imply that the four viral miRNAs work co-operatively to modulate ATM activity in response to DNA damage and to maintain viral latency, contributing to the tumorigenesis of NPC. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

New Insights from Elucidating the Role of LMP1 in Nasopharyngeal Carcinoma

Latent membrane protein 1 (LMP1) is an Epstein-Barr virus (EBV) oncogenic protein that has no intrinsic enzymatic activity or sequence homology to cellular or viral proteins. The oncogenic potential of LMP1 has been ascribed to pleiotropic signaling properties initiated through protein-protein interactions in cytosolic membrane compartments, but the effects of LMP1 extend to nuclear and extracellular processes. Although LMP1 is one of the latent genes required for EBV-immortalization of B cells, the biology of LMP1 in the pathogenesis of the epithelial cancer nasopharyngeal carcinoma (NPC) is more complex. NPC is prevalent in specific regions of the world with high incidence in southeast China. The epidemiology and time interval from seroconversion to NPC onset in adults would suggest the involvement of multiple risk factors that complement the establishment of a latent and persistent EBV infection. The contribution of LMP1 to EBV pathogenesis in polarized epithelia has only recently begun to be elucidated. Furthermore, the LMP1 gene has emerged as one of the most divergent sequences in the EBV genome. This review will discuss the significance of recent advances in NPC research from elucidating LMP1 function in epithelial cells and lessons that could be learned from mining LMP1 sequence diversity.

Exosomes in Nasopharyngeal Carcinoma

Exosomes are nanosized (30-100nm) membrane microvesicles secreted through a complex cellular process. Exosomes contain a variety of bioactive molecules, such as proteins, microRNAs(miRNAs or miRs) and long non-coding RNAs (lncRNAs), playing an important role in the cell-to-cell substance transportation and signal transduction. Nasopharyngeal carcinoma-related exosomes (NPC-Exo) have been identified in circulating blood and contribute to tumor cell proliferation, angiopoiesis, and immune tolerance through remodeling of tumor microenvironment (TME). Nasopharyngeal carcinoma-related exosomes may also induce epithelial-mesenchymal transition (EMT), thus promoting tumor metastasis and chemoradioresistance. Clinically, the exosomes may serve as novel biomarkers for diagnosis and targeted therapies of nasopharyngeal carcinoma. This review article updates the understanding of exosomes in nasopharyngeal carcinoma(NPC).

C-Terminal Farnesylation of UCH-L1 Plays a Role in Transport of Epstein-Barr Virus Primary Oncoprotein LMP1 to Exosomes

Exosomes are small vesicles that cells secrete into the extracellular space, and there is increasing evidence that they have pivotal roles in cell-to-cell communication in malignancy. It is reported also that EBV-associated malignant cells, including those derived from nasopharyngeal carcinoma (NPC) and B-cell lymphoma, secrete exosomes. These EBV-related exosomes may contain viral products such as latent membrane protein 1 (LMP1) and may contribute to cancer progression. The aim of this study was to investigate the mechanism by which those viral products are loaded in exosomes. In this study, we show for the first time that ubiquitin C-terminal hydrolase-L1 (UCH-L1) and its C-terminal farnesylation, a posttranslational lipid modification, contribute to this mechanism. Our results also suggest that inhibition of UCH-L1 farnesylation is a potential therapeutic target against cancer metastasis and invasion.

Increasing evidence shows that exosomes are key regulators in cancer cell-to-cell communication. Several reports on Epstein-Barr virus (EBV)-related malignancies demonstrate that latent membrane protein 1 (LMP1) secreted by exosomes derived from EBV- or LMP1-positive cells can promote cancer progression and metastasis. However, the mechanism by which LMP1 is loaded into exosomes is still poorly understood. Here, we examined whether the process of LMP1 loading into exosomes is linked to the multifunctional molecule of the ubiquitin system—ubiquitin C-terminal hydrolase-L1 (UCH-L1). For the first time, we demonstrate that LMP1 is physically associated with UCH-L1 and that directing of LMP1 to exosomes is mediated by C-terminal farnesylation of UCH-L1. Additionally, we found that the FTI-277 farnesyltransferase inhibitor reduces motility- and anchorage-independent growth of EBV-positive cells in functional assays. On the basis of our results, we conclude that C-terminal farnesylation of UCH-L1 is one of the key mechanisms by which LMP1 is sorted to exosomes. We hypothesize that inhibition of farnesylation with specific small-molecule inhibitors blocks exosome-mediated transfer of prometastatic molecules such as LMP1 during cancer cell-to-cell communications and thereby impedes the process of cancer invasion.

IMPORTANCE Exosomes are small vesicles that cells secrete into the extracellular space, and there is increasing evidence that they have pivotal roles in cell-to-cell communication in malignancy. It is reported also that EBV-associated malignant cells, including those derived from nasopharyngeal carcinoma (NPC) and B-cell lymphoma, secrete exosomes. These EBV-related exosomes may contain viral products such as latent membrane protein 1 (LMP1) and may contribute to cancer progression. The aim of this study was to investigate the mechanism by which those viral products are loaded in exosomes. In this study, we show for the first time that ubiquitin C-terminal hydrolase-L1 (UCH-L1) and its C-terminal farnesylation, a posttranslational lipid modification, contribute to this mechanism. Our results also suggest that inhibition of UCH-L1 farnesylation is a potential therapeutic target against cancer metastasis and invasion.

Dynamic Changes in Plasma MicroRNAs Have Potential Predictive Values in Monitoring Recurrence and Metastasis of Nasopharyngeal Carcinoma

Although circulating microRNAs (miRNAs) have already proven to be useful as diagnostic and prognostic biomarkers in nasopharyngeal carcinoma (NPC), the potential of these molecules to monitor patients over time has been less explored. This study aimed to analyze dynamic changes in plasma miRNAs before and after treatment and explore their clinical significance in monitoring recurrence and metastasis of NPC. Candidate miRNAs were screened by microarray analysis and validated by real-time quantitative polymerase chain reaction (RT-qPCR). In the follow-up cohort including 102 patients, blood samples (plasma) were collected before the treatment initiation, 3 months, 6 months, and 12 months after treatments, and at the time of any recurrence or metastasis. Among these plasma miRNAs, miR-9-3p, miR-124-3p, miR-892b, and miR-3676-3p were significantly upregulated (P = 0.018, P = 0.039, P = 0.001, and P = 0.01, resp.) after treatment compared with pretreatment, and the four plasma miRNAs were downregulated again at recurrence or metastasis (P < 0.001, P = 0.015, P = 0.003, and P = 0.026, resp.). The dynamic changes in plasma miRNAs after treatment reflect the outcome of the disease and have the potential to monitor recurrence and metastasis in patients with NPC.

The effect of Mepitel Film on acute radiation-induced skin reactions in head and neck cancer patients: a feasibility study

OBJECTIVE

Mepitel Film significantly decreases acute radiation-induced skin reactions in breast cancer patients. Here we investigated the feasibility of using Mepitel Film in head and neck cancer patients (ACTRN12614000932662).

METHODS

Out of a total of 36 head and neck cancer patients from New Zealand (NZ) (n = 24) and China (n = 12) recruited between June 2015 and December 2016, 33 patients complied with protocol. Of these, 11 NZ patients followed a management protocol; 11 NZ patients and 11 Chinese patients followed a prophylactic protocol. An area of the neck receiving a homogenous radiation dose of > 35 Gy was divided into two equal halves; one half was randomized to Film and the other to either Sorbolene cream (NZ) or Biafine cream (China). Skin reaction severity was measured by Radiation Induced Skin Reaction Assessment Scale and expanded Radiation Therapy Oncology Group toxicity criteria. Skin dose was measured by thermoluminescent dosimeters or gafchromic film.

RESULTS

Film decreased overall skin reaction severity (combined Radiation Induced Skin Reaction Assessment Scale score) by 29% and moist desquamation rates by 37% in the Chinese cohort and by 27 and 28%, respectively in the NZ cohort. Mepitel Film did not affect head movements but did not adhere well to the skin, particularly in males with heavy beard stubble, and caused itchiness, particularly in Chinese patients.

CONCLUSION

Mepitel Film reduced acute radiation-induced skin reactions in our head and neck cancer patients, particularly in patients without heavy stubble. Advances in knowledge: This is the first study to confirm the feasibility of using Mepitel Film in head and neck cancer patients.

Nasopharyngeal carcinoma super-enhancer-driven ETV6 correlates with prognosis

Nasopharyngeal carcinoma (NPC) most frequently occurs in southern China and southeast Asia. Epidemiology studies link NPC to genetic predisposition, Epstein-Barr virus (EBV) infection, and environmental factors. Genetic studies indicate that mutations in chromatin-modifying enzymes are the most frequent genetic alterations in NPC. Here, we used H3K27ac chromatin immune precipitation followed by deep sequencing (ChIP-seq) to define the NPC epigenome in primary NPC biopsies, NPC xenografts, and an NPC cell line, and compared them to immortalized normal nasopharyngeal or oral epithelial cells. We identified NPC-specific enhancers and found these enhancers were enriched with nuclear factor κB (NF-κB), IFN-responsive factor 1 (IRF1) and IRF2, and ETS family members ETS1 motifs. Normal cell-specific enhancers were enriched with basic leucine zipper family members and TP53 motifs. NPC super-enhancers with extraordinarily broad and high H3K27ac signals were also identified, and they were linked to genes important for oncogenesis including ETV6. ETV6 was also highly expressed in NPC biopsies by immunohistochemistry. High ETV6 expression correlated with a poor prognosis. Furthermore, we defined the EBV episome epigenetic landscapes in primary NPC tissue.

Serum EBV antibodies and LMP-1 in Polish patients with oropharyngeal and laryngeal cancer

Background

The association between Epstein-Barr virus (EBV) and the development of head and neck cancer was reported by many researchers. The aim of the present study was to detect EBV DNA and EBV antibodies in 110 Polish patients with oropharyngeal and laryngeal cancer compared to 40 healthy individuals.

Methods

Frozen tumor tissue fragments were tested using nested PCR assay for EBV DNA detection. Sera from all individuals were investigated using ELISA tests to detect the presence of VCA IgM and IgG, EBNA IgG, EA IgG.

Results

EBV DNA was detected in 52.7% of the patients (25% in controls). EBVCA were detected in 94.5%, EBNA in 96.4% and EA in 94.5% of patients. The significantly higher level of EA in the patients suggests EBV reactivation. The majority of patients (83%) were infected with wild-type EBV.

Conclusion

Our study showed that this variant seems to be associated with oropharyngeal and laryngeal cancer in the Polish population.

LncRNA CCAT1 modulates the sensitivity of paclitaxel in nasopharynx cancers cells via miR-181a/CPEB2 axis

Recent studies reported that long non-coding RNA (lncRNA) might play critical roles in regulating chemo-resistant of multiple types of cancer. This study aimed to investigate whether long non-coding RNA CCAT1 was involved in Paclitaxel resistance in nasopharyngeal carcinoma (NPC). qRT-PCR was used for testing the expression of CCAT1, miR-181a and CPEB2 in tumor tissues and NPC cancers. NPC cells were transfected with siRNAs to suppress the mRNA level of CCAT1 in NPC cells. MTT assays and flow cytometry analysis were used to assess the sensitivity of paclitaxel in NPC cells. Luciferase reporter assays were used to examine the interaction of CCAT1 or CPEB2 to miR-181a. Our findings revealed that the upregulated CCAT1 results in significantly enhancing paclitaxel resistance in nasopharyngeal cancer cells. Bioinformatics analysis and luciferase reporter assay indicated that the upregulated CCAT1 sponges miR-181a in NPC cells. Furthermore, RNA immuno-precipitation assays showed that miR-181a could directly bind to CCAT1 mRNA in NPC cells. We restored miR-181a in NPC cells, and found restoration of miR-181a re-sensitized the NPC cells to paclitaxel in vitro. In addition, our results also showed that miR-181a was a modulator of paclitaxel sensitivity due to its regulative effect on cell apoptosis via targeting CPEB2 in NPC cells. Taken together, lncRNA CCAT1 regulates the sensitivity of paclitaxel in NPC cells via miR-181a/CPEB2 axis.

Dissecting the regulation of EBV's BART miRNAs in carcinomas

Epstein-Barr virus (EBV) encodes multiple miRNAs known to contribute to its pathogenicity. Previous studies have found that the levels of some EBV miRNAs are 10–100 fold higher in biopsies and in tumor xenografts than in cells grown in culture. We have asked if these increased levels reflect transcriptional enhancement resulting from the tumor microenvironment, selection for increased levels of the EBV genome, or both. We measured the levels of BART miRNAs and their DNA templates in tumor xenografts induced from EBV-positive gastric carcinoma cells and EBV-negative gastric carcinoma cells expressing plasmid replicons encoding these miRNAs. We focused on BART miRNAs which are expressed in all tumors and found that they provide tumors selective growth advantages as xenografts. Stem-loop PCR and real-time PCR revealed that the xenografts expressed both higher levels of some miRNAs and viral DNA templates than did the corresponding cells in culture.

Analogies Between Cancer-Derived Extracellular Vesicles and Enveloped Viruses with an Emphasis on Human Breast Cancer

Purpose of Review

Cancer cells utilize extracellular vesicles (EVs) as a means of transferring oncogenic proteins and nucleic acids to other cells to enhance the growth and spread of the tumor. There is an unexpected amount of similarities between these small, membrane-bound particles and enveloped virions, including protein content, physical characteristics (i.e., size and morphology), and mechanisms of entry and exit into target cells.

Recent Findings

This review describes the attributes shared by both cancer-derived EVs, with an emphasis on breast cancer-derived EVs, and enveloped viral particles and discusses the methods by which virions can utilize the EV pathway as a means of transferring viral material and oncogenes to host cells. Additionally, the possible links between human papilloma virus and its influence on the miRNA content of breast cancer-derived EVs are examined.

Summary

The rapidly growing field of EVs is allowing investigators from different disciplines to enter uncharted territory. The study of the emerging similarities between cancer-derived EVs and enveloped virions may lead to novel important scientific discoveries.