Potential Interest in Circulating miR-BART17-5p As a Post-Treatment Biomarker for Prediction of Recurrence in Epstein-Barr Virus-Related Nasopharyngeal Carcinoma

5-Hydroxymethylcytosines in circulating cell-free DNA as a diagnostic biomarker for nasopharyngeal carcinoma

OBJECTIVE

To evaluate the diagnostic value of 5-hydroxymethylcytosines (5hmC) in circulating cell-free DNA (cfDNA) for nasopharyngeal carcinoma (NPC) and to develop a diagnostic model.

METHODS

Genome-wide 5hmC profiles in cfDNA from 174 NPC patients and 146 non-cancer individuals were analyzed using the 5hmC-Seal technique. A cfDNA 5hmC-based diagnostic model to identify NPC patients was developed using least absolute shrinkage and selection operator (LASSO) logistic regression, and performance was evaluated with receiver operating characteristic (ROC) curves and confusion matrices.

RESULTS

The 5hmC-Seal data from patients with NPC showed a different genome-wide distribution than non-tumor samples. Our initial analysis revealed a 12-gene-based 5hmC marker panel to be an accurate diagnostic model effectively distinguishing between NPC samples and non-cancerous samples (training set: area under curve (AUC)= 0.97 [95 % CI: 0.94-0.99]; and test set: AUC= 0.93 [95 % CI: 0.88-0.98]) superior to EBV DNA testing. The diagnostic score performed well in differentiating the non-cancer subjects from early-stage NPC (training set: AUC=0.99 [95 % CI: 0.98-1]; test set: AUC=0.98 [95 % CI: 0.95-1]), and advanced-stage NPC (training set: AUC=0.96 [95 % CI: 0.93-0.99]; test set: AUC=0.93 [95 % CI: 0.88-0.98]). Notably, in EBV-negative patients, the diagnostic scores showed excellent capacity for distinguishing EBV-negative patients with NPC from non-cancer subjects in both the training set (AUC= 0.94 [95 % CI: 0.88-1]) and test set (AUC=0.91 [95 % CI: 0.81-1]).

CONCLUSION

5hmC modifications in cfDNA are promising noninvasive biomarkers for NPC, offering high sensitivity and specificity, particularly for early-stage and EBV-negative NPC.

Recent advances in early detection of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) arises from the mucosal epithelium of the nasopharynx and is frequently located in the pharyngeal crypts. This is a highly aggressive malignant tumor that frequently leads to distant metastases in many cases and poses a significant public health challenge, particularly in certain geographic regions globally. This review discusses the epidemiology, risk factors, diagnosis, and treatment options for NPC, emphasizing the importance of early detection and comprehensive management strategies in improving patient outcomes. Moreover, the article explores the intricate mechanisms that cause NPC. Comprehending these fundamental principles can assist in creating specific prevention and therapy approaches for NPC. Recent advances in diagnostic methods, including imaging tests and molecular biomarkers, are emphasized to improve early diagnosis and individualized treatment strategies for individuals with NPC. The review also explores the most recent advancements in treating early-stage (stage I and II) NPC patients, highlighting the changing landscape of individualized therapy approaches for this particular set of patients.

Epstein-Barr virus microRNA miR-BART2-5p accelerates nasopharyngeal carcinoma metastasis by suppressing RNase Ⅲ endonuclease DICER1

The development and progression of nasopharyngeal carcinoma (NPC) is closely associated with Epstein-Barr virus (EBV) infection. NPC is usually asymptomatic until it spreads to other sites, and more than 70% of cases are classified as locally advanced disease at diagnosis. EBV-positive nasopharyngeal cancer tissues express only limited viral latent proteins, but express high levels of the EBV-encoded BamHI-A rightward transcript (BART) miRNA molecules. Here, we report that EBV-miRNA-BART2-5p (BART2-5p) promotes NPC cell invasion and metastasis in vivo and in vitro but has no effect on NPC cell proliferation and apoptosis. In addition, BART2-5p altered the mRNA and miRNA expression profiles of NPC cells. The development of human tumors has been reported to be associated with altered miRNAs expression, and overall miRNAs expression is reduced in many types of tumors. We found that BART2-5p downregulated the expression of several miRNAs that could exert oncogenic functions. Mechanistically, BART2-5p directly targets the RNase III endonuclease DICER1, inhibiting its function of cleaving double-stranded stem-loop RNA into short double-stranded RNA, which in turn causes altered expression of a series of key epithelial-mesenchymal transition molecules, and reverting DICER1 expression can rescue this phenotype. Furthermore, analysis from clinical samples showed a negative correlation between BART2-5p and DICER1 expression. According to our study, high expression of BART2-5p in tissues and plasma of patients with NPC is associated with poor prognosis. Our results suggest that, BART2-5p can accelerate NPC metastasis through modulating miRNA profiles which are mediated by DICER1, implying a novel role of EBV miRNAs in the pathogenesis of NPC.

Quantitative analysis of Epstein-Barr virus DNA in plasma and stomach biopsies of patients with gastric cancer

Epstein-Barr virus (EBV) associated gastric carcinoma (EBVaGC) is a subtype of gastric cancer with distinct histological and molecular features. The study aimed to assess the EBV DNA copy number and the prevalence of EBVaGC in gastric cancer samples taken from Iranian patients. The next aim was to assess whether the DNA and microRNAs EBV are present in plasma. EBV load was analyzed in 68 gastric cancer biopsies and compared with the results of EBV-encoded small RNA in situ hybridization (EBER-ISH) test in these patients. After the detection of 6 EBV miRNAs in gastric tissue by stem-loop RT-PCR, plasma samples were evaluated for the viral load and EBV miRNAs. Four gastric cancer cases were EBER -ISH positive (5.8%), with a significantly higher viral load than the remaining cases, 47,781 vs. 1909 copies/μg of tissue DNA. Here, was also found a significant difference in plasma EBV load between EBER-positive and EBER-negative cases. Although EBV miRNAs were detectable in all the EBER-positive tumors, the test did not detect any of these miRNAs among the plasma samples tested. Our data indicate that the prevalence of EBVaGC among Iranian patients with gastric cancer is lower than the global prevalence and although none of the EBV miRNAs were detected in plasma, evaluation of EBV microRNAs in tumor tissue, especially miR-BART7-3p, may constitute useful biomarkers for diagnosis of EBVaGC.

Nasopharyngeal Carcinoma and Its Microenvironment: Past, Current, and Future Perspectives

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy that raises public health concerns in endemic countries. Despite breakthroughs in therapeutic strategies, late diagnosis and drug resistance often lead to unsatisfactory clinical outcomes in NPC patients. The tumor microenvironment (TME) is a complex niche consisting of tumor-associated cells, such as fibroblasts, endothelial cells, leukocytes, that influences tumor initiation, progression, invasion, and metastasis. Cells in the TME communicate through various mechanisms, of note, exosomes, ligand-receptor interactions, cytokines and chemokines are active players in the construction of TME, characterized by an abundance of immune infiltrates with suppressed immune activities. The NPC microenvironment serves as a target-rich niche for the discovery of potential promising predictive or diagnostic biomarkers and the development of therapeutic strategies. Thus, huge efforts have been made to exploit the role of the NPC microenvironment. The whole picture of the NPC microenvironment remains to be portrayed to understand the mechanisms underlying tumor biology and implement research into clinical practice. The current review discusses the recent insights into the role of TME in the development and progression of NPC which results in different clinical outcomes of patients. Clinical interventions with the use of TME components as potential biomarkers or therapeutic targets, their challenges, and future perspectives will be introduced. This review anticipates to provide insights to the researchers for future preclinical, translational and clinical research on the NPC microenvironment.

OUP accepted manuscript

Background

Nasopharyngeal carcinoma is an Epstein-Barr virus (EBV)-associated tumor that is highly common in southern China. Our previous sequencing data demonstrated that the EBV-encoded microRNA BART8-3p was most upregulated in nasopharyngeal carcinoma (NPC) and was closely associated with the metastasis of NPC. However, the values of plasma BART8-3p in NPC patients have not yet been well characterized.

Material and Methods

We quantified plasma BART8-3p expression by quantitative real-time PCR in 205 newly diagnosed NPC patients. Kaplan-Meier analysis was used to compare overall survival (OS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRRFS) between the groups.

Results

Plasma pretreatment BART8-3p was highly expressed in NPC patients compared with healthy controls. Pretreatment BART8-3p yielded a 92% predictive value for detecting NPC. Importantly, BART8-3p decreased dramatically after therapy relative to pretreatment levels. High levels of pretreatment or post-treatment BART8-3p were associated with worse OS, DMFS, and LRRFS. Multivariate analysis showed that high pretreatment or post-treatment BART8-3p was an independent unfavorable prognostic marker for OS (HR 3.82, 95% CI 1.77-8.24, P = .001 or HR 2.74, 95% CI 1.27-5.91, P = .010), DMFS (HR 2.82, 95% CI 1.36-5.85, P = .005 or HR 3.27, 95% CI 1.57-6.81, P = .002), and LRRFS (HR 1.94, 95% CI 1.12-3.35, P = .018 or HR 2.03, 95% CI 1.14-3.62, P = .016) in NPC. Subgroup analysis revealed that for patients with locally advanced NPC with high levels of pretreatment BART8-3p (n = 58), more cycles of chemotherapy (≥6 cycles) tended to prolong OS (P = .070). Over 50% (6/11) patients with high levels of post-treatment BART8-3p presented distant metastasis.

Conclusion

Plasma BART8-3p is a promising biomarker for the detection and prognosis of NPC.

MicroRNA and Other Non-Coding RNAs in Epstein-Barr Virus-Associated Cancers

EBV is a direct causative agent in around 1.5% of all cancers. The oncogenic properties of EBV are related to its ability to activate processes needed for cellular proliferation, survival, migration, and immune evasion. The EBV latency program is required for the immortalization of infected B cells and involves the expression of non-coding RNAs (ncRNAs), including viral microRNAs. These ncRNAs have different functions that contribute to virus persistence in the asymptomatic host and to the development of EBV-associated cancers. In this review, we discuss the function and potential clinical utility of EBV microRNAs and other ncRNAs in EBV-associated malignancies. This review is not intended to be comprehensive, but rather to provide examples of the importance of ncRNAs.

Research status and prospects of biomarkers for nasopharyngeal carcinoma in the era of high‑throughput omics (Review)

As a malignant tumor type, nasopharyngeal carcinoma (NPC) is characterized by distinct geographical, ethnic and genetic differences; presenting a major threat to human health in many countries, especially in Southern China. At present, no accurate and effective methods are available for the early diagnosis, efficacious evaluation or prognosis prediction for NPC. As such, a large number of patients have locoregionally advanced NPC at the time of initial diagnosis. Many patients show toxic reactions to overtreatment and have risks of cancer recurrence and distant metastasis owing to insufficient treatment. To solve these clinical problems, high‑throughput '‑omics' technologies are being used to screen and identify specific molecular biomarkers for NPC. Because of the lack of comprehensive descriptions regarding NPC biomarkers, the present study summarized the research progress that has been made in recent years to discover NPC biomarkers, highlighting the existing problems that require exploration. In view of the lack of authoritative reports at present, study design factors that affect the screening of biomarkers are also discussed here and prospects for future research are proposed to provide references for follow‑up studies of NPC biomarkers.

Epstein-Barr virus microRNAs in the pathogenesis of human cancers

The Epstein-Barr Virus (EBV) is a gamma-herpesvirus involved with a variety of human cancers, notably the endemic Burkitt lymphoma and nasopharyngeal carcinoma. In 2004, EBV was described as one the first known human oncoviruses to encode viral microRNAs (miRNAs), and these molecules were found to interact with viral and host targets. EBV miRNAs modulate biological processes that are critical for carcinogenesis, contributing to cell transformation and tumor progression of EBV-associated cancers. Herein we review and discuss EBV miRNAs as modulators of viral biology and carcinogenesis, as well as their usefulness as putative markers to monitor the onset, progression, and recurrence of cancers associated with the EBV infection.

Clinical utility of Epstein-Barr virus DNA and other liquid biopsy markers in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor ubiquitously associated with the Epstein-Barr virus (EBV), which is highly prevalent in South China, Southeast Asia, and North Africa. Despite being a highly radio-sensitive and treatable cancer, a majority of NPC patients are diagnosed in their advanced stage, and locoregional and distant relapses following definitive treatment contribute largely to cancer-specific mortality among these patients. Given that EBV-driven NPC is the predominant variant seen in endemic regions, various EBV detection methods have been developed and are utilized in screening, prognostication, and post-treatment surveillance of NPC patients. While the Immunoglobulin A (IgA) serology assay is the most extensively studied EBV detection method, the detection of plasma EBV DNA released during replication or cellular apoptosis has shown superior outcomes in endemic population screening, prognostication, and detection of distant relapse. Furthermore, there is emerging evidence on the use of circulating tumor cells, microRNAs, DNA hypermethylation, and combination assays in various clinical scenarios. Herein, this paper provides a comprehensive overview of the relevant studies using various EBV detection techniques in the management of NPC. Specifically, the recent advances, clinical evidence, and challenges associated with the clinical application of EBV liquid biopsies in population screening, prognostication, and surveillance of NPC are presented.

Viral non-coding RNAs: Stealth strategies in the tug-of-war between humans and herpesviruses

Oncogenic DNA viruses establish lifelong infections in humans, and they cause cancers, often in immunocompromised patients, despite anti-viral immune surveillance targeted against viral antigens. High-throughput sequencing techniques allowed the field to identify novel viral non-coding RNAs (ncRNAs). ncRNAs are ideal factors for DNA viruses to exploit; they are non-immunogenic to T cells, thus viral ncRNAs can manipulate host cells without evoking adaptive immune responses. Viral ncRNAs may still trigger the host innate immune response, but many viruses encode decoys/inhibitors to counter-act and evade recognition. In addition, ncRNAs can be secreted to the extracellular space and influence adjacent cells to create a pro-viral microenvironment. In this review, we present recent progress in understanding interactions between oncoviruses and ncRNAs including small and long ncRNAs, microRNAs, and recently identified viral circular RNAs. In addition, potential clinical applications for ncRNA will be discussed. Extracellular ncRNAs are suggested to be diagnostic and prognostic biomarkers and, with the realization of the importance of viral ncRNAs in tumorigenesis, approaches to target critical viral ncRNAs are emerging. Further understanding of viral utilization of ncRNAs will advance anti-viral therapeutics beyond conventional medication and vaccination.

Epstein-Barr virus BART microRNAs in EBV- associated Hodgkin lymphoma and gastric cancer

Background

EBV produces miRNAs with important functions in cancer growth, tumor invasion and host immune surveillance. The discovery of EBV miR-BARTs is recent, and most of their functions are still unknown. Nonetheless, some new studies underline their key roles in EBV-associated malignancies.

Main body

In EBV-associated tumors, the expression profile of miR-BARTs varies according to the cell type, autophagic process and signals received from the tumor microenvironment. By the same way of interest is the interaction between tumor cells and the tumor environment by the release of selected EBV miR-BARTs in addition to the tumor proteins trough tumor exosomes.

Conclusion

In this review, we discuss new findings regarding EBV miR-BARTs in Hodgkin lymphoma and gastric cancer. The recent discovery that miRNAs are released by exosomes, including miR-BARTs, highlights the importance of tumor and microenvironment interplay with more specific effects on the host immune response.

Epstein-Barr Virus miR-BART17-5p Promotes Migration and Anchorage-Independent Growth by Targeting Kruppel-Like Factor 2 in Gastric Cancer

Epstein-Barr virus (EBV) infects more than 90% of the global population and is associated with a variety of tumors including nasopharyngeal carcinoma, Hodgkin lymphoma, natural killer/T lymphoma, and gastric carcinoma. In EBV-associated gastric cancer (EBVaGC), highly expressed EBV BamHI A rightward transcripts (BART) miRNAs may contribute to tumorigenesis with limited viral antigens. Despite previous studies on the targets of BART miRNAs, the functions of all 44 BART miRNAs have not been fully clarified. Here, we used RNA sequencing data from the Cancer Genome Atlas to find genes with decreased expression in EBVaGC. Furthermore, we used AGS cells infected with EBV to determine whether expression was reduced by BART miRNA. We showed that the expression of Kruppel-like factor 2 (KLF2) is lower in AGS-EBV cells than in the AGS control. Using bioinformatics analysis, four BART miRNAs were selected to check whether they suppress KLF2 expression. We found that only miR-BART17-5p directly down-regulated KLF2 and promoted gastric carcinoma cell migration and anchorage-independent growth. Our data suggest that KLF2 functions as a tumor suppressor in EBVaGC and that miR-BART17-5p may be a valuable target for effective EBVaGC treatment.

The roles of EBV-encoded microRNAs in EBV-associated tumors

Epstein-Barr virus (EBV) is believed to be a pathogen causing a number of human cancers, but the pathogenic mechanisms remain unclear. An increasing number of studies have indicated that EBV-encoded microRNAs (EBV miRNAs) are expressed in a latency type- and tumor type-dependent manner, playing important roles in the development and progression of EBV-associated tumors. By targeting one or more genes of the virus and the host, EBV miRNAs are responsible for the deregulation of a variety of viral and host cell biological processes, including viral replication, latency maintenance, immune evasion, cell apoptosis and metabolism, and tumor proliferation and metastasis. In addition, some EBV miRNAs can be used as excellent diagnostic, prognostic and treatment efficacy predictive biomarkers for EBV-associated tumors. More importantly, EBV miRNA-targeting therapeutics have emerged and have been developing rapidly, which may open a new era in the treatment of EBV-associated tumors in the near future.

Vesicle-bound EBV-BART13-3p miRNA in circulation distinguishes nasopharyngeal from other head and neck cancer and asymptomatic EBV-infections

Cell‐free microRNA (miRNA) in biofluids released by tumors in either protein or vesicle‐bound form, represent promising minimally‐invasive cancer biomarkers. However, a highly abundant non‐tumor background in human plasma and serum complicates the discovery and detection of tumor‐selective circulating miRNAs. We performed small RNA sequencing on serum and plasma RNA from Nasopharyngeal Carcinoma (NPC) patients. Collectively, Epstein Barr virus‐encoded miRNAs, more so than endogenous miRNAs, signify presence of NPC. However, RNAseq‐based EBV miRNA profiles differ between NPC patients, suggesting inter‐tumor heterogeneity or divergent secretory characteristics. We determined with sensitive qRT‐PCR assays that EBV miRNAs BART7‐3p, BART9‐3p and BART13‐3p are actively secreted by C666.1 NPC cells bound to extracellular vesicles (EVs) and soluble ribonucleoprotein complexes. Importantly, these miRNAs are expressed in all primary NPC tumor biopsies and readily detected in nasopharyngeal brushings from both early and late‐stage NPC patients. Increased levels of BART7‐3p, BART9‐3p and particularly BART13‐3p, distinguish NPC patient sera from healthy controls. Receiver operating characteristic curve analysis using sera from endemic NPC patients, other head and neck cancers and individuals with asymptomatic EBV‐infections reveals a superior diagnostic performance of EBV miRNAs over anti‐EBNA1 IgA serology and EBV‐DNA load (AUC 0.87–0.96 vs 0.86 and 0.66 respectively). The high specificity of circulating EBV‐BART13‐3p (97%) for NPC detection is in agreement with active secretion from NPC tumor cells. We conclude EV‐bound BART13‐3p in circulation is a promising, NPC‐selective, biomarker that should be considered as part of a screening strategy to identify NPC in endemic regions.

What's new?

Analysis of DNA from human tumor viruses in patient blood is a non‐invasive screening method for individuals at risk for developing cancer. A drawback is over‐diagnosis as these sensitive methods also detect non‐cancer‐related infections. Here the authors show by RNA sequencing and PCR amplification that a microRNA (BART13‐3p) encoded by the Epstein–Barr Virus (EBV) is associated with circulating vesicles in patients with nasopharyngeal carcinoma, thus distinguishing between cancer and non‐cancer‐related EBV infections.

The emerging role of Epstein-Barr virus encoded microRNAs in nasopharyngeal carcinoma

Epstein-Barr virus (EBV) is an oncogenic herpes virus that is closely associated with the initiation and development of nasopharyngeal carcinoma (NPC), lymphoma and other malignant tumors. EBV encodes 44 mature miRNAs that regulate viral and host cell gene expression and plays a variety of roles in biological functions and the development of cancer. In this review, we summarized the biological functions and molecular mechanisms of Epstein-Barr virus-encoded microRNAs (EBV miRNAs) in tumor immune evasion, proliferation, anti-apoptosis, invasion, metastasis and as a potential biomarker for NPC diagnosis and prognosis. The knowledge generated by EBV miRNAs can be used for EBV miRNA-based precision cancer treatments in the near future.

The oncogenic role of Epstein-Barr virus-encoded microRNAs in Epstein-Barr virus-associated gastric carcinoma

Epstein–Barr virus (EBV) infection is detected in various epithelial malignancies, such as nasopharyngeal carcinoma (NPC) and gastric cancer (GC). EBV comprises some unique molecular features and encodes viral genes and microRNAs (miRNAs) by its own DNA sequence. EBV genes are required to maintain latency and contribute to oncogenic property. miRNAs encoded by EBV have been shown to contribute to initiation and progression of EBV‐related malignancies. By a number of genomic profiling studies, some EBV miRNAs were confirmed to be highly expressed in EBV‐associated gastric cancer (EBVaGC) samples and cell lines. The majority host targets of the EBV miRNAs are important for promoting cell growth and inhibiting apoptosis, facilitating cell survival and immune evasion. However, the integrated molecular mechanisms related to EBV miRNAs remain to be investigated. In this review, we summarized the crucial role of EBV miRNAs in epithelial malignancies, especially in EBVaGC. Collectively, EBV miRNAs play a significant role in the viral and host gene regulation network. Understanding the comprehensive potential targets and relevant functions of EBV miRNAs in gastric carcinogenesis might provide better clinical translation.

Progression of understanding for the role of Epstein-Barr virus and management of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is very common in southern China and Southeast Asia. In regions where NPC is endemic, undifferentiated subtypes constitute most cases and are invariably associated with Epstein-Barr virus (EBV) infection, whereas the differentiated subtype is more common in other parts of the world. Undifferentiated NPC is a unique malignancy with regard to its epidemiology, etiology, and clinical presentation. Clinically, NPC is highly invasive and metastatic, but sensitive to both chemotherapy and radiotherapy (RT). Overall prognosis has dramatically improved over the past three decades because of advances in management, including the improvement of RT technology, the broader application of chemotherapy, and more accurate disease staging. Despite the excellent local control with modern RT, distant failure remains a challenging problem. Advances in molecular technology have helped to elucidate the molecular pathogenesis of NPC. This article reviews the contribution of EBV gene products to NPC pathogenesis and the current management of NPC.

Role of Epstein-Barr Virus in the Development of Nasopharyngeal Carcinoma

Southern China experiences larger extent of total cancer pathologies, of which nasopharyngeal carcinoma has the highest incidence under otorhinolaryngeal malignant carcinomas. Risk factor of nasopharyngeal carcinoma varies from hereditary causes to virus infection, among which Epstein-Barr virus (EBV) infection is the mostly investigated. The study into mechanism of EBV in occurrence, development and prognosis of nasopharyngeal carcinoma has been studied for several decades. The pathophysiology in making of EBV into a cancerogen includes proteins as latent membrane protein 1 (LMPs) and nucleic acids as micro-RNAs. In this paper, we reviewed till date studies focusing on relationship between EBV and nasopharyngeal carcinoma.