Effective treatment of metastatic forms of Epstein-Barr virus-associated nasopharyngeal carcinoma with a novel adenovirus-based adoptive immunotherapy

Leveraging oncovirus-derived antigen against the viral malignancies in adoptive cell therapies

Adoptive cell therapies (ACTs) have revolutionized cancer immunotherapy, prompting exploration into their application against oncoviruses. Oncoviruses such as human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), and Epstein-Barr virus (EBV) contribute significantly (12-25%) to human malignancies through direct or indirect oncogenic mechanisms. These viruses persistently or latently infect cells, disrupt cellular homeostasis and pathways, challenging current antiviral treatment paradigms. Moreover, viral infections pose additional risks in the setting of long-term cancer therapy and lead to morbidity and mortality. Virally encoded oncoproteins, which are tumor-restricted, immunologically foreign, and even uniformly expressed, represent promising targets for patient-tailored ACTs. This review elucidates the rationale for leveraging viral antigen-specific ACTs in combating viral-associated malignancies. On this basis, ongoing preclinical studies consolidate our understanding of harnessing ACTs against viral malignancies, underscoring their potential to eradicate viruses implicated in cancer progression. Furthermore, we scrutinize the current landscape of clinical trials focusing on virus-specific ACTs and discuss their implications for therapeutic advancement.

Aging trajectories of memory CD8 + T cells differ by their antigen specificity

Memory T cells are a highly dynamic and heterogeneous population that is maintained by cytokine-driven homeostatic proliferation interspersed with episodes of antigen-mediated expansion and contraction which affect their functional state and their durability. This heterogeneity complicates studies on the impact of aging on global human memory cells, specifically, it is unclear how aging drives memory T cell dysfunction. Here, we used chronic infection with Epstein-Barr virus (EBV) to assess the influence of age on memory states at the level of antigen-specific CD8 + T cells. We find that in young adults (<40 years), EBV-specific CD8 + T cells assume preferred differentiation states depending on their peptide specificity. By age >65-years, different T cell specificities had undergone largely distinct aging trajectories, which had in common a loss in adaptive and a gain in innate immunity signatures. No evidence was seen for cellular senescence or exhaustion. While naïve/stem-like EBV-specific T cells disappeared with age, T cell diversity of EBV-specific memory cells did not change or even increased. In summary, by controlling for antigen specificity we uncover age-associated shifts in gene expression and TCR diversity that have implications for optimizing vaccination strategies and adoptive T cell therapy.

Geographic EBV variants confound disease-specific variant interpretation and predict variable immune therapy responses

ABSTRACT

Epstein-Barr virus (EBV) is a potent carcinogen linked to hematologic and solid malignancies and causes significant global morbidity and mortality. Therapy using allogeneic EBV-specific lymphocytes shows promise in certain populations, but the impact of EBV genome variation on these strategies remains unexplored. To address this, we sequenced 217 EBV genomes, including hematologic malignancies from Guatemala, Peru, Malawi, and Taiwan, and analyzed them alongside 1307 publicly available EBV genomes from cancer, nonmalignant diseases, and healthy individuals across Africa, Asia, Europe, North America, and South America. These included, to our knowledge, the first natural killer (NK)/T-cell lymphoma (NKTCL) EBV genomes reported outside of East Asia. Our findings indicate that previously proposed EBV genome variants specific to certain cancer types are more closely tied to geographic origin than to cancer histology. This included variants previously reported to be specific to NKTCL but were prevalent in EBV genomes from other cancer types and healthy individuals in East Asia. After controlling for geographic region, we did identify multiple NKTCL-specific variants associated with a 7.8-fold to 21.9-fold increased risk. We also observed frequent variations in EBV genomes that affected peptide sequences previously reported to bind common major histocompatibility complex alleles. Finally, we found several nonsynonymous variants spanning the coding sequences of current vaccine targets BALF4, BKRF2, BLLF1, BXLF2, BZLF1, and BZLF2. These results highlight the need to consider geographic variation in EBV genomes when devising strategies for exploiting adaptive immune responses against EBV-related cancers, ensuring greater global effectiveness and equity in prevention and treatment.

Immunotherapy for recurrent or metastatic nasopharyngeal carcinoma

Immunotherapy, particularly immune checkpoint inhibitors (ICIs), such as anti-programmed death 1/programmed death-ligand 1 (PD-1/PD-L1) therapy, has emerged as a pivotal treatment modality for solid tumors, including recurrent or metastatic nasopharyngeal carcinoma (R/M-NPC). Despite the advancements in the utilization of ICIs, there is still room for further improving patient outcomes. Another promising approach to immunotherapy for R/M-NPC involves adoptive cell therapy (ACT), which aims to stimulate systemic anti-tumor immunity. However, individual agent therapies targeting dendritic cells (DCs) appear to still be in the clinical trial phase. This current review underscores the potential of immunotherapy as a valuable adjunct to the treatment paradigm for R/M-NPC patients. Further research is warranted to enhance the efficacy of immunotherapy through the implementation of strategies such as combination therapies and overcoming immune suppression. Additionally, the development of a biomarker-based scoring system is essential for identifying suitable candidates for precision immunotherapy.

Efficacy and Safety of Cell-based Immunotherapy in The Treatment of Recurrent or Metastatic Nasopharyngeal Carcinoma - A Systematic Review and Meta-analysis

BACKGROUND

Recurrent/Metastatic Nasopharyngeal Carcinoma (RM-NPC) remains difficult to treat and contributes to considerable mortality. The first-line treatment for RM-NPC is Gemcitabine and Cisplatin and second-line treatment options differ. The endemic variant of NPC is associated with Epstein-Barr Virus (EBV). Therefore, Cell-based Immunotherapy (CBI) targeting EBV-specific RM-NPC may be effective.

METHODS

We systematically searched PubMed, Embase and the Cochrane Library for randomised or observational studies investigating the efficacy and safety of CBI in the treatment of RM-NPC. We performed all meta-analyses using the random-effects model. Studies were further stratified by endemicity, nature of disease and drug type to investigate for potential between-study heterogeneity and additional pre-specified tests were employed to assess for publication bias.

RESULTS

We screened 1,671 studies and included 13 studies with 403 participants in the systematic review, of which nine studies were eligible for meta-analysis. The use of CBI monotherapy as second or subsequent line treatment for EBV-positive RM-NPC revealed an ORR of 10 % (95 %CI = 3 %-29 %), median PFS of 2.37 months (95 %CI = 1.23-3.51) and median OS of 10.16 months (95 %CI = 0.67-19.65). For EBV-specific Cytotoxic T-Lymphocyte monotherapy, the pooled PD rate was 54 % (95 %CI = 9 %-93 %), SD rate was 22 % (95 %CI = 2 %-75 %) and incidence rate of any grade adverse events was 45 %. For Dendritic Cell monotherapy, a PD rate of 80 % (95 % CI = 29 %-98 %), SD rate of 11 % (95 % CI = 0 %-82 %) and incidence rate of any grade adverse events of 29 % was achieved.

CONCLUSION

CBI monotherapy demonstrates some activity in pre-treated RM-NPC. More trials are needed to better understand how to integrate CBI into RM-NPC care.

Nasopharyngeal carcinoma: current views on the tumor microenvironment's impact on drug resistance and clinical outcomes

The incidence of nasopharyngeal carcinoma (NPC) exhibits significant variations across different ethnic groups and geographical regions, with Southeast Asia and North Africa being endemic areas. Of note, Epstein-Barr virus (EBV) infection is closely associated with almost all of the undifferentiated NPC cases. Over the past three decades, radiation therapy and chemotherapy have formed the cornerstone of NPC treatment. However, recent advancements in immunotherapy have introduced a range of promising approaches for managing NPC. In light of these developments, it has become evident that a deeper understanding of the tumor microenvironment (TME) is crucial. The TME serves a dual function, acting as a promoter of tumorigenesis while also orchestrating immunosuppression, thereby facilitating cancer progression and enabling immune evasion. Consequently, a comprehensive comprehension of the TME and its intricate involvement in the initiation, progression, and metastasis of NPC is imperative for the development of effective anticancer drugs. Moreover, given the complexity of TME and the inter-patient heterogeneity, personalized treatment should be designed to maximize therapeutic efficacy and circumvent drug resistance. This review aims to provide an in-depth exploration of the TME within the context of EBV-induced NPC, with a particular emphasis on its pivotal role in regulating intercellular communication and shaping treatment responses. Additionally, the review offers a concise summary of drug resistance mechanisms and potential strategies for their reversal, specifically in relation to chemoradiation therapy, targeted therapy, and immunotherapy. Furthermore, recent advances in clinical trials pertaining to NPC are also discussed.

Virus-specific T-cells from third party or transplant donors for treatment of EBV lymphoproliferative diseases arising post hematopoietic cell or solid organ transplantation

EBV+ lymphomas constitute a significant cause of morbidity and mortality in recipients of allogeneic hematopoietic cell (HCT) and solid organ transplants (SOT). Phase I and II trials have shown that in HCT recipients, adoptive transfer of EBV-specific T-cells from the HCT donor can safely induce durable remissions of EBV+ lymphomas including 70->90% of patients who have failed to respond to treatment with Rituximab. More recently, EBV-specific T-cells generated from allogeneic 3rd party donors have also been shown to induce durable remission of EBV+ lymphomas in Rituximab refractory HCT and SOT recipients. In this review, we compare results of phase I and II trials of 3rd party and donor derived EBV-specific T-cells. We focus on the attributes and limitations of each product in terms of access, safety, responses achieved and durability. The limited data available regarding donor and host factors contributing to T cell persistence is also described. We examine factors contributing to treatment failures and approaches to prevent or salvage relapse. Lastly, we summarize strategies to further improve results for virus-specific immunotherapies for post-transplant EBV lymphomas.

Combinations of radiotherapy with immunotherapy in nasopharyngeal carcinoma

BACKGROUND

The treatment of nasopharyngeal carcinoma (NPC) is currently based on concurrent chemoradiotherapy. The prognosis of early NPC is better, while the prognosis of advanced NPC is poor. Immunotherapy is becoming increasingly commonly employed in clinical practice as a new strategy for treating malignant tumors. It has shown promising results in the treatment of certain malignant tumors, making it a current clinical research hotspot.

METHODS

This review summarizes the current immunotherapy on NPC, highlighting the application of immunotherapy and radiotherapy in the treatment of NPC.

RESULTS

X-rays can either increase or suppress anti-tumor immune responses through various pathways and mechanisms. Immune checkpoint inhibitors can usually enhance X-ray-induced anti-tumor immune responses. Detecting the immune checkpoint markers and tumor mutation markers, and the functional status of effector cells in patients can aid in the development of individualized treatment that improves the treatment efficacy with reducing drug resistance and adverse reactions. The development of a multivalent vaccine for NPC will help improve the efficacy of the vaccine. Combining techniques that increase the tumor antigens release, such as radiotherapy and oncolytic virus vaccines, may enhance the ability of the immune response.

CONCLUSIONS

To shed further light on the application of immunotherapy in NPC, large pooled studies must accumulate sufficient cases with detailed exposure data.

Precision drugs for recurrent or metastatic nasopharyngeal carcinoma (Review)

Nasopharyngeal carcinoma (NPC) is a malignancy that is common in Southern China, South-East Asia and North Africa. Platinum-based chemotherapy is currently the main treatment option for the first-line therapy of recurrent and/or metastatic NPC (RM-NPC). However, the outcome of patients with advanced disease remains poor after treatment with standard chemotherapy, as patients eventually became resistant to chemotherapy. Other strategies, such as targeted therapy and immunotherapy, offer alternative options for patients due to their reported efficacy and manageable toxicities. This suggests that these modalities, either as monotherapy or in combination with chemotherapy, may serve as viable treatment options for RM-NPC. The present review provides a comprehensive summary of the clinical data of targeted therapy and immunotherapy for RM-NPC, with the aim of broadening the understanding of RM-NPC management.

Precision medicine in nasopharyngeal carcinoma: comprehensive review of past, present, and future prospect

Nasopharyngeal carcinoma (NPC) is an aggressive malignancy with high propensity for lymphatic spread and distant metastasis. It is prominent as an endemic malignancy in Southern China and Southeast Asia regions. Studies on NPC pathogenesis mechanism in the past decades such as through Epstein Barr Virus (EBV) infection and oncogenic molecular aberrations have explored several potential targets for therapy and diagnosis. The EBV infection introduces oncoviral proteins that consequently hyperactivate many promitotic pathways and block cell-death inducers. EBV infection is so prevalent in NPC patients such that EBV serological tests were used to diagnose and screen NPC patients. On the other hand, as the downstream effectors of oncogenic mechanisms, the promitotic pathways can potentially be exploited therapeutically. With the apparent heterogeneity and distinct molecular aberrations of NPC tumor, the focus has turned into a more personalized treatment in NPC. Herein in this comprehensive review, we depict the current status of screening, diagnosis, treatment, and prevention in NPC. Subsequently, based on the limitations on those aspects, we look at their potential improvements in moving towards the path of precision medicine. The importance of recent advances on the key molecular aberration involved in pathogenesis of NPC for precision medicine progression has also been reported in the present review. Besides, the challenge and future outlook of NPC management will also be highlighted.

Immunotherapy for nasopharyngeal carcinoma: Current status and prospects (Review)

Nasopharyngeal carcinoma (NPC) is an epithelial tumor located in the nasopharynx and is highly associated with Epstein‑Barr virus (EBV) infection. Although radiotherapy alone can cure ~90% of patients with early‑stage disease, >70% of patients with NPC have locoregionally advanced or metastatic disease at the first diagnosis due to the insidious and aggressive nature of NPC. After comprehensive radiochemotherapy, 20‑30% of patients with advanced NPC still fail treatment, mainly due to recurrence and/or metastasis (R/M). Conventional salvage treatments, such as radiotherapy, chemotherapy and surgery, are suboptimal and frequently accompanied by severe adverse effects and limited efficacy. In recent years, immunotherapy has emerged as a promising treatment modality for R/M NPC. An increasing number of clinical studies have investigated the safety and efficacy of immunotherapy for advanced NPC and have shown considerable progress. In the present review, the rationale for the use of immunotherapy to treat NPC was summarized and the current status, progress and challenges of NPC clinical research on different immunotherapeutic approaches were highlighted, including immune checkpoint inhibitors, vaccines, immunomodulators, adoptive cell transfer and EBV‑specific monoclonal antibodies. The comprehensive overview of immunotherapy in NPC may provide insight for clinical practice and future investigation.

Adoptive T-cell therapy targeting Epstein-Barr virus as a treatment for multiple sclerosis

Emergence of a definitive link between Epstein-Barr virus (EBV) and multiple sclerosis has provided an impetus to develop immune-based therapies to target EBV-infected B cells. Initial studies with autologous EBV-specific T-cell therapy demonstrated that this therapy is safe with minimal side effects and more importantly multiple patients showed both symptomatic and objective neurological improvements including improved quality of life, reduction of fatigue and reduced intrathecal IgG production. These observations have been successfully extended to an 'off-the-shelf' allogeneic EBV-specific T-cell therapy manufactured using peripheral blood lymphocytes of healthy seropositive individuals. This adoptive immunotherapy has also been shown to be safe with encouraging clinical responses. Allogeneic EBV T-cell therapy overcomes some of the limitations of autologous therapy and can be rapidly delivered to patients with improved therapeutic potential.

Banking on virus-specific T cells to fulfill the need for off-the-shelf cell therapies

Adoptively transferred virus-specific T cells (VSTs) have shown remarkable safety and efficacy for the treatment of virus-associated diseases and malignancies in hematopoietic stem cell transplant (HSCT) recipients, for whom VSTs are derived from the HSCT donor. Autologous VSTs have also shown promise for the treatment of virus-driven malignancies outside the HSCT setting. In both cases, VSTs are manufactured as patient-specific products, and the time required for procurement, manufacture, and release testing precludes their use in acutely ill patients. Further, Good Manufacturing Practices-compliant products are expensive, and failures are common in virus-naive HSCT donors and patient-derived VSTs that are rendered anergic by immunosuppressive tumors. Hence, highly characterized, banked VSTs (B-VSTs) that can be used for multiple unrelated recipients are highly desirable. The major challenges facing B-VSTs result from the inevitable mismatches in the highly polymorphic and immunogenic human leukocyte antigens (HLA) that present internally processed antigens to the T-cell receptor, leading to the requirement for partial HLA matching between the B-VST and recipient. HLA mismatches lead to rapid rejection of allogeneic T-cell products and graft-versus-host disease induced by alloreactive T cells in the infusion product. Here, we summarize the clinical outcomes to date of trials of B-VSTs used for the treatment of viral infections and malignancies and their potential as a platform for chimeric antigen receptors targeting nonviral tumors. We will highlight the properties of VSTs that make them attractive off-the-shelf cell therapies, as well as the challenges that must be overcome before they can become mainstream.

The role of Epstein-Barr virus in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a metastasis-prone malignancy closely associated with the Epstein-Barr virus (EBV). Despite ubiquitous infection of EBV worldwide, NPC incidences displayed predominance in certain ethnic groups and endemic regions. The majority of NPC patients are diagnosed with advanced-stage disease, as a result of anatomical isolation and non-specific clinical manifestation. Over the decades, researchers have gained insights into the molecular mechanisms underlying NPC pathogenesis as a result of the interplay of EBV infection with several environmental and genetic factors. EBV-associated biomarkers were also used for mass population screening for the early detection of NPC. EBV and its encoded products also serve as potential targets for the development of therapeutic strategies and tumour-specific drug delivery. This review will discuss the pathogenic role of EBV in NPC and efforts in exploiting the potential of EBV-associated molecules as biomarkers and therapeutic targets. The current knowledge on the role of EBV and its associated products in NPC tumorigenesis, development and progression will offer a new outlook and potential intervention strategy against this EBV-associated malignancy.

Immunotherapeutic approaches in EBV-associated nasopharyngeal carcinoma

Epstein-Barr virus (EBV) was the first tumor virus in humans. Nasopharyngeal carcinoma (NPC) accounts for approximately 60% of the 200,000 new tumor cases caused by EBV infection worldwide each year. NPC has an insidious onset and is highly malignant, with more than 70% of patients having intermediate to advanced disease at the time of initial diagnosis, and is strongly implicated in epithelial cancers as well as malignant lymphoid and natural killer/T cell lymphomas. Over 90% of patients with confirmed undifferentiated NPC are infected with EBV. In recent decades, much progress has been made in understanding the molecular mechanisms of NPC and developing therapeutic approaches. Radiotherapy and chemotherapy are the main treatment options for NPC; however, they have a limited efficacy in patients with locally advanced or distant metastatic tumors. Tumor immunotherapy, including vaccination, adoptive cell therapy, and immune checkpoint blockade, represents a promising therapeutic approach for NPC. Significant breakthroughs have recently been made in the application of immunotherapy for patients with recurrent or metastatic NPC (RM-NPC), indicating a broad prospect for NPC immunotherapy. Here, we review important research findings regarding immunotherapy for NPC patients and provide insights for future research.

Updates on Epstein-Barr Virus (EBV)-Associated Nasopharyngeal Carcinoma: Emphasis on the Latent Gene Products of EBV

Nasopharyngeal carcinoma (NPC) is an uncommon type of malignancy/cancer worldwide. However, NPC is an endemic disease in southeast Asia and southern China and the reasons behind the underlying for such changes are unclear. Even though the Epstein-Barr infection (EBV) has been suggested as an important reason for undistinguishable NPC, the EBV itself is not adequate to source this type of cancer. The risk factors, for example, genetic susceptibility, and environmental factors might be associated with EBV to undertake a part in the NPC carcinogenesis. Normal healthy people have a memory B cell pool where the EBV persists, and any disturbance of this connection leads to virus-associated B cell malignancies. Less is known about the relationship between EBV and epithelial cell tumors, especially the EBV-associated nasopharyngeal carcinoma (EBVaNPC) and EBV-associated gastric carcinoma (EBVaGC). Currently, it is believed that premalignant genetic changes in epithelial cells contribute to the aberrant establishment of viral latency in these tumors. The early and late phases of NPC patients' survival rates vary significantly. The presence of EBV in all tumor cells presents prospects for the development of innovative therapeutic and diagnostic techniques, despite the fact that the virus's exact involvement in the carcinogenic process is presently not very well known. EBV research continues to shed light on the carcinogenic process, which is important for a more comprehensive knowledge of tumor etiology and the development of targeted cancer therapeutics. In order to screen for NPC, EBV-related biomarkers have been widely used in a few high-incidence locations because of their close associations with the risks of NPC. The current review highlights the scientific importance of EBV and its possible association with NPC.

Therapeutic approaches to Epstein-Barr virus cancers

Epstein-Barr virus (EBV) establishes a lifelong latent infection that can be a causal agent for a diverse spectrum of cancers and autoimmune disease. A complex and dynamic viral lifecycle evades eradication by the host immune system and confounds antiviral therapeutic strategies. To date, there are no clinically approved vaccines or therapies that selectively target EBV as the underlying cause of EBV-associated disease. Here, we review the challenges and recent advances in the development of EBV-specific therapeutics for treatment of EBV-associated cancers.

Reconstitution of EBV-directed T cell immunity by adoptive transfer of peptide-stimulated T cells in a patient after allogeneic stem cell transplantation for AITL

Reconstitution of the T cell repertoire after allogeneic stem cell transplantation is a long and often incomplete process. As a result, reactivation of Epstein-Barr virus (EBV) is a frequent complication that may be treated by adoptive transfer of donor-derived EBV-specific T cells. We generated donor-derived EBV-specific T cells by stimulation with peptides representing defined epitopes covering multiple HLA restrictions. T cells were adoptively transferred to a patient who had developed persisting high titers of EBV after allogeneic stem cell transplantation for angioimmunoblastic T-cell lymphoma (AITL). T cell receptor beta (TCRβ) deep sequencing showed that the T cell repertoire of the patient early after transplantation (day 60) was strongly reduced and only very low numbers of EBV-specific T cells were detectable. Manufacturing and in vitro expansion of donor-derived EBV-specific T cells resulted in enrichment of EBV epitope-specific, HLA-restricted T cells. Monitoring of T cell clonotypes at a molecular level after adoptive transfer revealed that the dominant TCR sequences from peptide-stimulated T cells persisted long-term and established an EBV-specific TCR clonotype repertoire in the host, with many of the EBV-specific TCRs present in the donor. This reconstituted repertoire was associated with immunological control of EBV and with lack of further AITL relapse.

A characteristic feature of all herpesviruses is their persistence in the host’s body after primary infection. Hence, the host’s immune system is confronted with the problem to control these viruses life-long. When the immune system is severely compromised, for example after stem cell transplantation from a foreign (allogeneic) donor, these viruses can reappear, as they persist in the host’s body life-long after primary infection. Epstein-Barr virus (EBV) is a herpesvirus that can cause life-threatening complications after stem cell transplantation and only reinforcement of the host’s immune system can reestablish control over the virus. Here we show that ex vivo manufactured EBV-specific T cells can reestablish long-term control of EBV and that these cells persist in the host’s body over months. These results give us a better understanding of viral immune reconstitution post-transplant and of clinically-relevant T cell populations against EBV.

DNA immunotherapy targeting BARF1 induces potent anti-tumor responses against Epstein-Barr-virus-associated carcinomas

Latent Epstein-Barr virus (EBV) infection is associated with several types of cancer. Several clinical studies have targeted EBV antigens as immune therapeutic targets with limited efficacy of EBV malignancies, suggesting that additional targets might be important. BamHI-A rightward frame 1 (BARF1) is an EBV antigen that is highly expressed in EBV+ nasopharyngeal carcinoma (NPC) and EBV-associated gastric carcinoma (EBVaGC). BARF1 antigen can transform human epithelial cells in vivo. BARF1-specific antibodies and cytotoxic T cells were detected in some EBV+ NPC patients. However, BARF1 has not been evaluated as an antigen in the context of therapeutic immunization. Its possible importance in this context is unclear. Here, we developed a synthetic-DNA-based expression cassette as immunotherapy targeting BARF1 (pBARF1). Immunization with pBARF1 induced potent antigen-specific humoral and T cell responses in vivo. Immunization with pBARF1 plasmid impacted tumor progression through the induction of CD8+ T cells in novel BARF1+ carcinoma models. Using an in vivo imaging system, we observed that pBARF1-immunized animals rapidly cleared cancer cells. We demonstrated that pBARF1 can induce antigen-specific immune responses that can impact cancer progression. Further study of this immune target is likely important as part of therapeutic approaches for EBV+ malignancies.

EBV-associated diseases: Current therapeutics and emerging technologies

EBV is a prevalent virus, infecting >90% of the world's population. This is an oncogenic virus that causes ~200,000 cancer-related deaths annually. It is, in addition, a significant contributor to the burden of autoimmune diseases. Thus, EBV represents a significant public health burden. Upon infection, EBV remains dormant in host cells for long periods of time. However, the presence or episodic reactivation of the virus increases the risk of transforming healthy cells to malignant cells that routinely escape host immune surveillance or of producing pathogenic autoantibodies. Cancers caused by EBV display distinct molecular behaviors compared to those of the same tissue type that are not caused by EBV, presenting opportunities for targeted treatments. Despite some encouraging results from exploration of vaccines, antiviral agents and immune- and cell-based treatments, the efficacy and safety of most therapeutics remain unclear. Here, we provide an up-to-date review focusing on underlying immune and environmental mechanisms, current therapeutics and vaccines, animal models and emerging technologies to study EBV-associated diseases that may help provide insights for the development of novel effective treatments.

Co-Stimulatory Molecules during Immune Control of Epstein Barr Virus Infection

The Epstein Barr virus (EBV) is one of the prominent human tumor viruses, and it is efficiently immune-controlled in most virus carriers. Cytotoxic lymphocytes strongly expand during symptomatic primary EBV infection and in preclinical in vivo models of this tumor virus infection. In these models and patients with primary immunodeficiencies, antibody blockade or deficiencies in certain molecular pathways lead to EBV-associated pathologies. In addition to T, NK, and NKT cell development, as well as their cytotoxic machinery, a set of co-stimulatory and co-inhibitory molecules was found to be required for EBV-specific immune control. The role of CD27/CD70, 4-1BB, SLAMs, NKG2D, CD16A/CD2, CTLA-4, and PD-1 will be discussed in this review. Some of these have just been recently identified as crucial for EBV-specific immune control, and for others, their important functions during protection were characterized in in vivo models of EBV infection and its immune control. These insights into the phenotype of cytotoxic lymphocytes that mediate the near-perfect immune control of EBV-associated malignancies might also guide immunotherapies against other tumors in the future.

Epstein-Barr Virus: Should We Still Invest in Vaccines or Focus on Predictive Tests?

The complex interplay between host and EBV has made it difficult to elaborate useful vaccines protecting against EBV diseases. It is encouraging to see that EBV vaccine programs have started to incorporate different arms of the immune system. An array of argument calls for a realistic goal for vaccine strategies which should be preventing EBV diseases, rather than EBV infection. EBV is the primary cause of infectious mononucleosis and is associated with epithelial cell carcinomas, as well as lymphoid malignancies. Parallel to this need, one could propose priorities for future research: (i) identification of surrogate predictive markers for the development of EBV diseases (ii) determination of immune correlates of protection in animal models and humans.

The inhibitory effect of rBCG on EB virus-positive tumours using an EB virus fusion gene

At present, studies have found that latent Epstein-Barr virus (EBV) infection is associated with a variety of human tumours, and a vaccine is not available in this field. In this research, RT-PCR was used to obtain BZLF1 (immediately expressed early antigen Z) and LMP2 (latent membrane protein 2) cDNA from EBV. A ZLP2 fusion gene containing a linker sequence that encoded the polypeptide (Gly₄Ser)₃ was obtained using the sequence splicing overlap extension method. Then, ZLP2 was inserted into pMV261 cells, and the recombinant plasmid pMV-ZLP2 was transformed into BCG competent cells. After EB virus-positive tumour cell (NPRC18) cancer models were established with C57BL/6 J mice, tumour weight, tumour formation time and mouse survival conditions were analyzed, and flow cytometry was used to analyze the quantities of CD8 + and CD4 + T cells. HE staining was used to detect and analyze lymphocyte infiltration, and statistical analysis was used to analyze the immunological effect of recombinant BCG (rBCG). Compared with the control group, rBCG could significantly prolong the survival time of mice, slow tumour growth and delay tumour formation time. Recombinant BCG exhibits an obvious immune effect in mice and an inhibitory effect on EBV-positive cancer.Key points• AZLP2 fusion gene with BZLF1 and LMP2 of EB virus was constructed.• ZLP2 fusion gene was expressed with rBCG.• rBCG with ZLP2 has an obvious effect on EBV-positive cancer.

Prophylactic and Therapeutic EBV Vaccines: Major Scientific Obstacles, Historical Progress, and Future Direction

The Epstein-Barr virus (EBV) infects more than 95% of adults worldwide and is associated with various malignant tumors and immune diseases, imparting a huge disease burden on the human population. Available EBV vaccines are imminent. Prophylactic vaccines can effectively prevent the spread of infection, whereas therapeutic vaccines mainly stimulate cell-mediated immunity and kill infected cells, thus curbing the development of malignant tumors. Nevertheless, there are still no approved EBV vaccines after decades of effort. The complexity of the EBV life cycle, the lack of appropriate animal models, and the limited reports on adjuvant selection and immune responses are gravely impeding progress in EBV vaccines. The soluble gp350 vaccine could reduce the incidence of infectious mononucleosis (IM), which seemed to offer hope, but could not prevent EBV infection. Continuous research and vaccine trials provide deep insights into the structural biology of viruses, the designs for immunogenicity, and the evolving vaccine platforms. Moreover, the new vaccine candidates are expected to achieve further success via combined immunization to elicit both a dual protection of B cells and epithelial cells, and sustainable immunization against infected cells at several phases of infection.

Nasopharyngeal carcinoma: an evolving paradigm

The past three decades have borne witness to many advances in the understanding of the molecular biology and treatment of nasopharyngeal carcinoma (NPC), an Epstein-Barr virus (EBV)-associated cancer endemic to southern China, southeast Asia and north Africa. In this Review, we provide a comprehensive, interdisciplinary overview of key research findings regarding NPC pathogenesis, treatment, screening and biomarker development. We describe how technological advances have led to the advent of proton therapy and other contemporary radiotherapy approaches, and emphasize the relentless efforts to identify the optimal sequencing of chemotherapy with radiotherapy through decades of clinical trials. Basic research into the pathogenic role of EBV and the genomic, epigenomic and immune landscape of NPC has laid the foundations of translational research. The latter, in turn, has led to the development of new biomarkers and therapeutic targets and of improved approaches for individualizing immunotherapy and targeted therapies for patients with NPC. We provide historical context to illustrate the effect of these advances on treatment outcomes at present. We describe current preclinical and clinical challenges and controversies in the hope of providing insights for future investigation.

Exploration of a Novel Prognostic Risk Signature and Its Effect on the Immune Response in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a highly invasive and metastatic carcinoma with different molecular characteristics and clinical outcomes. In this work, we aimed to establish a novel gene signature that could predict the prognosis of NPC patients. A total of 13 significant genes between the recurrence/metastasis (RM) group and the no recurrence/metastasis (no-RM) group were identified by machine learning from RNA-Seq data including 60 NPC tumor biopsies. Based on these genes, a 4-mRNA signature (considering U2AF1L5, TMEM265, GLB1L and MLF1) was identified. Receiver operating characteristic (ROC) and Kaplan-Meier (K-M) analyses indicated that this signature had good prognostic value for NPC. The overall survival (OS) and progression-free survival (PFS) of the patients in the high-risk group were significantly shorter than those of the patients in the low-risk group (p = 0.00126 and p = 0.000059, respectively). The area under the ROC curve (AUC) values of the 4-mRNA signature were higher than those of T stage and N stage for OS (0.893 vs 0.619 and 0.582, respectively) and PFS (0.86 vs 0.538 and 0.622, respectively). Furthermore, the 4-mRNA signature was closely associated with cell proliferation and the immune response. The expression of GLB1L and TMEM265 was associated with the level of tumor-infiltrating immune cells (r > 0.4, p < 0.05). We have validated the model through measuring the expression levels of the 4-mRNA signature by qRT-PCR, in an independent cohort of NPC patients. Here, we report a novel gene signature that can serve as a new tool for predicting the prognosis of NPC patients.

Epstein Barr Virus Exploits Genetic Susceptibility to Increase Multiple Sclerosis Risk

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) for which both genetic and environmental risk factors have been identified. The strongest synergy among them exists between the MHC class II haplotype and infection with the Epstein Barr virus (EBV), especially symptomatic primary EBV infection (infectious mononucleosis) and elevated EBV-specific antibodies. In this review, we will summarize the epidemiological evidence that EBV infection is a prerequisite for MS development, describe altered EBV specific immune responses in MS patients, and speculate about possible pathogenic mechanisms for the synergy between EBV infection and the MS-associated MHC class II haplotype. We will also discuss how at least one of these mechanisms might explain the recent success of B cell-depleting therapies for MS. While a better mechanistic understanding of the role of EBV infection and its immune control during MS pathogenesis is required and calls for the development of innovative experimental systems to test the proposed mechanisms, therapies targeting EBV-infected B cells are already starting to be explored in MS patients.

Immunotherapy in Recurrent/Metastatic Squamous Cell Carcinoma of the Head and Neck

Head and neck cancer is the 6^th most common cancer worldwide with the most common histology being squamous cell carcinoma (HNSCC). While the majority of patients present at a stage where curative intent therapy is possible, when patients recur and/or develop metastatic disease, outcomes are generally poor, especially with systemic therapy alone, and they lag behind other solid tumors. Over the last decade immunotherapy has revolutionized the field of oncology, and anti-PD-1-based therapy has changed the standard of care in recurrent/metastatic (R/M) HNSCC as well. With these gains have come new questions to continue to move the field forward. In this review, we discuss the tumor immune microenvironment and predictive biomarkers and current status and future directions for immunotherapy in recurrent/metastatic head and neck cancer.

Immunotherapy for Head and Neck Cancer

Head and neck squamous cell carcinomas (HNSCC) remain an important cause of global cancer morbidity and mortality. Historically, outcomes for patients with recurrent or metastatic disease were poor with limited treatment options. In recent decades, the demographic profile of this disease has evolved with an increase in human papilloma virus-associated oropharyngeal carcinoma and a decrease in tobacco-related disease. The treatment paradigm for HNSCC has rapidly evolved with identification of novel, immune-directed, therapeutic strategies that take advantage of immune dysregulation commonly seen in HNSCC. This review summarizes recent developments in this field and discusses emerging strategies for future therapies.

Virus-specific T cells for malignancies - then, now and where to?

Purpose of Review

Virus-associated malignancies are a global health burden, constituting 10-12% of cancers worldwide. As these tumors express foreign viral antigens that can elicit specific T cell responses, virus-directed immunotherapies are a promising treatment strategy. Specifically, adoptive cell transfer of virus-specific T cells (VSTs) has demonstrated the potential to eradicate cancers associated with certain viruses.

Recent Findings

Initial studies in 1990s first showed that VSTs specific for the Epstein-Barr virus (EBVSTs) can induce complete remissions in patients with post-transplant lymphoproliferative disease. Since then, studies have validated the specificity and safety of VSTs in multiple lymphomas and solid malignancies. However, challenges remain to optimize this platform for widespread use, including enhancing potency and persistence, overcoming the immunosuppressive tumor microenvironment, and streamlining manufacturing processes that comply with regulatory requirements.

Summary

This review focuses on data from clinical trials evaluating VSTs directed against three viruses (EBV, HPV and MCPyV), as well as recent preclinical and clinical advances, and potential future directions.

Complete response to PD-1 blockade following EBV-specific T-cell therapy in metastatic nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an Epstein–Barr virus (EBV)-associated heterogeneous disease and is characterized by peritumoral immune infiltrate. Adoptive T-cell therapy (ACT) has emerged as a potential therapeutic strategy for NPC. However, the tumor microenvironment remains a major roadblock for the successful implementation of ACT in clinical settings. Expression of checkpoint molecules by malignant cells can inhibit the effector function of adoptively transferred EBV-specific T cells. Here we present a novel case report of a patient with metastatic NPC who was successfully treated with a combination of EBV-specific ACT and programmed cell death-1 blockade therapy. Following combination immunotherapy, the patient showed complete resolution of metastatic disease with no evidence of disease relapse for 22 months. Follow-up immunological analysis revealed dramatic restructuring of the global T-cell repertoire that was coincident with the clinical response. This case report provides an important platform for translating these findings to a larger cohort of NPC patients.

Sustained Clinical Improvement in a Subset of Patients With Progressive Multiple Sclerosis Treated With Epstein-Barr Virus-Specific T Cell Therapy

Background: Increasing evidence indicates a role for Epstein–Barr virus (EBV) in the pathogenesis of multiple sclerosis (MS). EBV-infected autoreactive B cells might accumulate in the central nervous system because of defective cytotoxic CD8⁺ T cell immunity. We have previously reported results of a phase I clinical trial of autologous EBV-specific T cell therapy in MS 6 months after treatment.

Objective: To investigate longer-term outcomes in MS patients who received autologous EBV-specific T cell therapy.

Methods: We assessed participants 2 and 3 years after completion of T cell therapy.

Results: We collected data from all 10 treated participants at year 2 and from 9 participants at year 3. No serious treatment-related adverse events were observed. Four participants had at least some sustained clinical improvement at year 2, including reduced fatigue in three participants, and reduced Expanded Disability Status Scale score in two participants. Three participants experienced a sustained improvement in at least some symptoms at year 3. More sustained improvement was associated with higher EBV-specific CD8⁺ T cell reactivity in the administered T cell product.

Conclusion: Autologous EBV-specific T cell therapy is well-tolerated, and some degree of clinical improvement can be sustained for up to 3 years after treatment.

The Role of EBV-Encoded LMP1 in the NPC Tumor Microenvironment: From Function to Therapy

Nasopharyngeal carcinoma (NPC) is closely associated with Epstein-Barr virus (EBV) infection. It is also characterized by heavy infiltration with non-malignant leucocytes. The EBV-encoded latent membrane protein 1 (LMP1) is believed to play an important role in NPC pathogenesis by virtue of its ability to activate multiple cell signaling pathways which collectively promote cell proliferation and survival, angiogenesis, invasiveness, and aerobic glycolysis. LMP1 also affects cell-cell interactions, antigen presentation, and cytokine and chemokine production. Here, we discuss how LMP1 modulates local immune responses that contribute to the establishment of the NPC tumor microenvironment. We also discuss strategies for targeting the LMP1 protein as a novel therapy for EBV-driven malignancies.

A new approach for cellular immunotherapy of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV)-associated malignancy that is highly prevalent in Southern China and South-East Asia. EBV-targeted immunotherapy remains a goal in the development of novel treatment strategies. A novel adenoviral polyepitope-based immunotherapy has been developed to rapidly generate high frequency EBV-specific T cells to treat patients with refractory or metastatic disease.

'Off-the-shelf' allogeneic antigen-specific adoptive T-cell therapy for the treatment of multiple EBV-associated malignancies

Background

Epstein-Barr virus (EBV), an oncogenic human gammaherpesvirus, is associated with a wide range of human malignancies of epithelial and B-cell origin. Recent studies have demonstrated promising safety and clinical efficacy of allogeneic ‘off-the-shelf’ virus-specific T-cell therapies for post-transplant viral complications.

Methods

Taking a clue from these studies, we developed a highly efficient EBV-specific T-cell expansion process using a replication-deficient AdE1-LMPpoly vector that specifically targets EBV-encoded nuclear antigen 1 (EBNA1) and latent membrane proteins 1 and 2 (LMP1 and LMP2), expressed in latency II malignancies.

Results

These allogeneic EBV-specific T cells efficiently recognized human leukocyte antigen (HLA)-matched EBNA1-expressing and/or LMP1 and LMP2-expressing malignant cells and demonstrated therapeutic potential in a number of in vivo models, including EBV lymphomas that emerged spontaneously in humanized mice following EBV infection. Interestingly, we were able to override resistance to T-cell therapy in vivo using a ‘restriction-switching’ approach, through sequential infusion of two different allogeneic T-cell therapies restricted through different HLA alleles. Furthermore, we have shown that inhibition of the programmed cell death protein-1/programmed death-ligand 1 axis in combination with EBV-specific T-cell therapy significantly improved overall survival of tumor-bearing mice when compared with monotherapy.

Conclusion

These findings suggest that restriction switching by sequential infusion of allogeneic T-cell therapies that target EBV through distinct HLA alleles may improve clinical response.

Monocytic Myeloid-Derived Suppressor Cells Underpin Resistance to Adoptive T Cell Therapy in Nasopharyngeal Carcinoma

Advanced, late-stage Epstein-Barr virus (EBV)-positive nasopharyngeal carcinoma (NPC) is incurable, and its treatment remains a clinical and therapeutic challenge. Results from a phase II clinical trial in advanced NPC patients employing a combined chemotherapy and EBV-specific T cell (EBVST) immunotherapy regimen showed a response rate of 71.4%. Longitudinal analysis of patient samples showed that an increase in EBV DNA plasma concentrations and the peripheral monocyte-to-lymphocyte ratio negatively correlated with overall survival. These parameters were combined into a multivariate analysis to stratify patients according to risk of death. Immunophenotyping at serial time points showed that low-risk individuals displayed significantly decreased amounts of monocytic myeloid-derived suppressor cells postchemotherapy, which subsequently influenced successful cytotoxic T-lymphocyte (CTL) immunotherapy. Examination of the low-risk group, 2 weeks post-EBVST infusion, showed that individuals with a greater overall survival possessed an increased frequency of CD8 central and effector memory T cells, together with higher levels of plasma interferon (IFN)-γ, and cytotoxic lymphocyte-associated transcripts. These results highlight the importance of the rational selection of chemotherapeutic agents and consideration of their impact on both systemic immune responses and downstream cellular immunotherapy outcomes.

Chapter XX Antiviral Treatment and Cancer Control

Hepatitis B virus (HBV), hepatitis C virus (HCV), human papilloma virus (HPV), Epstein-Barr virus (EBV), human T-cell lymphotropic virus type 1 (HTLV-1), Kaposi's sarcoma-associated herpesvirus (KSHV), and Merkel cell polyomavirus (MCV) contribute to about 10-15% global burden of human cancers. Conventional chemotherapy or molecular target therapies have been used to treat virus-associated cancers. However, a more proactive approach would be the use of antiviral treatment to suppress or eliminate viral infections to prevent the occurrence of cancer in the first place. Antiviral treatments against chronic HBV and HCV infection have achieved this goal, with significant reduction in the incidence of hepatocellular carcinoma in treated patients. Antiviral treatments for EBV, KSHV, and HTLV-1 had limited success in treating refractory EBV-associated lymphoma and post-transplant lymphoproliferative disorder, KSHV-associated Kaposi's sarcoma in AIDS patients, and HTLV-1-associated acute, chronic, and smoldering subtypes of adult T-cell lymphoma, respectively. Therapeutic HPV vaccine and RNA interference-based therapies for treating HPV-associated infection or cervical cancers also showed some encouraging results. Taken together, antiviral therapies have yielded promising results in cancer prevention and treatment. More large-scale studies in a real-world setting are necessary to confirm the efficacy of antiviral therapy. Further investigation for more effective and convenient antiviral regimens warrants more attention.

Vaccination against the Epstein-Barr virus

Epstein-Barr virus (EBV) was the first human tumor virus being discovered and remains to date the only human pathogen that can transform cells in vitro. 55 years of EBV research have now brought us to the brink of an EBV vaccine. For this purpose, recombinant viral vectors and their heterologous prime-boost vaccinations, EBV-derived virus-like particles and viral envelope glycoprotein formulations are explored and are discussed in this review. Even so, cell-mediated immune control by cytotoxic lymphocytes protects healthy virus carriers from EBV-associated malignancies, antibodies might be able to prevent symptomatic primary infection, the most likely EBV-associated pathology against which EBV vaccines will be initially tested. Thus, the variety of EBV vaccines reflects the sophisticated life cycle of this human tumor virus and only vaccination in humans will finally be able to reveal the efficacy of these candidates. Nevertheless, the recently renewed efforts to develop an EBV vaccine and the long history of safe adoptive T cell transfer to treat EBV-associated malignancies suggest that this oncogenic γ-herpesvirus can be targeted by immunotherapies. Such vaccination should ideally implement the very same immune control that protects healthy EBV carriers.

Joining Forces: Improving Clinical Response to Cellular Immunotherapies with Small-Molecule Inhibitors

Adoptive T cell therapy (ACT) has emerged as a powerful therapeutic tool against both hematological and virus-associated cancers. However, extension of this success to solid cancers has been challenging owing to intratumoral mechanisms that induce a hostile immunosuppressive tumor microenvironment (TME). Delineating the impact of tumor-intrinsic adaptive resistance mechanisms on immune-based therapies is essential to improve long-term efficacy. We discuss the different tumor-intrinsic factors that lead to resistance to ACT. We highlight the potential of repurposing molecular targeted therapies to modulate immune responses and override intratumor resistance to ACT. Finally, we discuss the potential of combining targeted therapy and ACT as a new paradigm to improve the clinical efficacy of cancer therapeutics.

The emerging data on choice of optimal therapy for locally advanced nasopharyngeal carcinoma

PURPOSE OF REVIEW

We focus on the emerging data from randomized clinical trials for optimal integration of induction, concurrent, and/or adjuvant chemotherapy with intensity-modulated radiotherapy in locally advanced nasopharyngeal carcinoma (NPC), and the use of plasma Epstein-Barr virus (EBV) DNA for risk stratification.

RECENT FINDINGS

Several phase 3 trials have shown that induction chemotherapy followed by concurrent chemoradiation (CRT) improved overall survival or disease-free survival when compared to CRT alone in stage III/IV NPC who is at high risk of distant metastases. The benefit of adjuvant chemotherapy following CRT when compared to CRT alone is uncertain. There are increasing clinical data supporting the use of plasma EBV DNA for risk stratification. There are growing clinical data supporting the integration of immune checkpoint inhibitors into the induction, concurrent, and/or adjuvant/maintenance phase of treatment in locally advanced NPC.

SUMMARY

Concurrent chemoradiation remains the standard treatment backbone in locally advanced NPC. There is level 1 evidence for induction chemotherapy followed by CRT in stage III/IV NPC. There is increasing evidence against the indiscriminate use of adjuvant chemotherapy following CRT. With the increasing treatment intensification, future treatment algorithm in NPC should incorporate plasma EBV DNA and other biomarkers for risk stratification and treatment selection.

Probing Reconstituted Human Immune Systems in Mice With Oncogenic γ-Herpesvirus Infections

Mice with reconstituted human immune systems can mount cell-mediated immune responses against the human tumor viruses Epstein Barr virus (EBV) and Kaposi sarcoma associated herpesvirus (KSHV). Primarily cytotoxic lymphocytes protect the vast majority of persistently infected carriers of these tumor viruses from the respective malignancies for life. Thus, EBV and KSHV infection can teach us how this potent immune control is induced, what phenotype and functions characterize the protective lymphocyte compartments and if similar immune responses could be induced by vaccination. This review will summarize similarities and differences between EBV and KSHV associated pathologies and their immune control in patients and mice with reconstituted human immune systems. Furthermore, it will high-light which aspects of the near perfect immune control can be modeled in the latter preclinical animal models and discuss their relevance for cancer immunology in general.

The Therapeutic Potential of Targeting BARF1 in EBV-Associated Malignancies

Epstein-Barr virus (EBV) is closely linked to the development of a number of human cancers. EBV-associated malignancies are characterized by a restricted pattern of viral latent protein expression which is sufficient for the virus to both initiate and sustain cell growth and to protect virus-infected cells from immune attack. Expression of these EBV proteins in malignant cells provides an attractive target for therapeutic intervention. Among the viral proteins expressed in the EBV-associated epithelial malignancies, the protein encoded by the BamHI-A rightward frame 1 (BARF1) is of particular interest. BARF1 is a viral oncoprotein selectively expressed in latently infected epithelial cancers, nasopharyngeal carcinoma (NPC) and EBV-positive gastric cancer (EBV-GC). Here, we review the roles of BARF1 in oncogenesis and immunomodulation. We also discuss potential strategies for targeting the BARF1 protein as a novel therapy for EBV-driven epithelial cancers.

Redirecting T Cells against Epstein-Barr Virus Infection and Associated Oncogenesis

The Epstein-Barr virus (EBV) is associated with lymphomas and carcinomas. For some of these, the adoptive transfer of EBV specific T cells has been therapeutically explored, with clinical success. In order to avoid naturally occurring EBV specific autologous T cell selection from every patient, the transgenic expression of latent and early lytic viral antigen specific T cell receptors (TCRs) to redirect T cells, to target the respective tumors, is being developed. Recent evidence suggests that not only TCRs against transforming latent EBV antigens, but also against early lytic viral gene products, might be protective for the control of EBV infection and associated oncogenesis. At the same time, these approaches might be more selective and cause less collateral damage than targeting general B cell markers with chimeric antigen receptors (CARs). Thus, EBV specific TCR transgenic T cells constitute a promising therapeutic strategy against EBV associated malignancies.

Current management of stage IV nasopharyngeal carcinoma without distant metastasis

Up to one in four patients with nasopharyngeal carcinoma present with non-metastatic stage IV disease (i.e. T4 or N3). Distinct failure patterns exist, despite the routine adoption of contemporary treatment modalities such as intensity modulated radiotherapy and systemic chemotherapy. Concurrent chemoradiotherapy (CCRT) followed by adjuvant chemotherapy or induction chemotherapy followed by CCRT are commonly employed in this setting, with the latter emerging as the preferred option. Additionally, emerging radiation technologies like proton therapy has become available offering new opportunities for prevention of radiation-induced side effects. This article reviews not only the current treatment strategies, but also discusses novel ways to tackle this challenging disease with respect to the patterns of failure.

The Role of Dendritic Cells in Immune Control and Vaccination against -Herpesviruses

The two human oncogenic -herpesviruses, Epstein Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus (KSHV), are prototypic pathogens that are controlled by T cell responses. Despite their ubiquitous distribution, persistent infections and transforming potential, most carriers' immune systems control them for life. Therefore, they serve as paradigms of how near-perfect cell-mediated immune control can be initiated and maintained for decades. Interestingly, EBV especially quite efficiently avoids dendritic cell (DC) activation, and little evidence exists that these most potent antigen-presenting cells of the human body are involved in the priming of immune control against this tumor virus. However, DCs can be harnessed therapeutically to expand virus-specific T cells for adoptive transfer therapy of patients with virus-associated malignancies and are also currently explored for vaccinations. Unfortunately, despite 55 and 25 years of research on EBV and KSHV, respectively, the priming of their immune control that belongs to the most robust and durable immune responses in humans still remains unclear.

In vitro evaluation of the therapeutic effectiveness of EBV-LMP2 recombinant adenovirus vaccine in nasopharyngeal carcinoma

Immunotherapeutic strategies based on Epstein-Barr virus (EBV) latent membrane protein 2 (LMP2) antigen-specific cytotoxic T lymphocytes (CTLs) have been proven to boost LMP2-specific CTL responses in patients with nasopharyngeal carcinoma (NPC). Such strategies can produce clinical benefits in some patients with NPC. Currently, the major challenge limiting the use of immunotherapy for NPC is its low clinical response rate. The efficacy of immunotherapy based on EBV-LMP2 specific CTLs depends mainly on their cytotoxic activity, but no studies have been conducted to elucidate this activity. In this study, laser confocal scanning microscopy (LCSM) and real-time cell analysis (RTCA) were used to evaluate the killing function and its underlying mechanism of LMP2-specific CTLs. LCSM showed that LMP2-specific CTLs recognize and kill target cells expressing viral escape protein LMP2, and that the killing rate is related to the number of CTLs adhering to the target cells. LMP2-specific CTL-mediated cytotoxicity is rate limited by the time required for effective contact and recognition between CTLs and target cells. RTCA showed that the protective effect of LMP2-specific CTLs required an appropriate effector-to-target ratio, and that LMP2-specific CTLs could not eradicate residual target cells at a low effector-to-target ratio. Moreover, our results revealed that LMP2-specific CTL responses involve two independent but complementary mechanisms: the perforin/granzyme and Fas/FasL pathways. Therefore, we have elucidated, for the first time, the selective cytotoxicity and mechanism by which LMP2-specific CTLs induced by the rAd-LMP2 vaccine kill target cells and have explored the killing mode and several key parameters of killing mediated by LMP2-specific CTLs. Our study will contribute to the knowledge of vaccines targeting EBV-LMP2 and to the improvement of immunotherapeutic strategies.

Latency and lytic replication in Epstein-Barr virus-associated oncogenesis

Epstein-Barr virus (EBV) was the first tumour virus identified in humans. The virus is primarily associated with lymphomas and epithelial cell cancers. These tumours express latent EBV antigens and the oncogenic potential of individual latent EBV proteins has been extensively explored. Nevertheless, it was presumed that the pro-proliferative and anti-apoptotic functions of these oncogenes allow the virus to persist in humans; however, recent evidence suggests that cellular transformation is not required for virus maintenance. Vice versa, lytic EBV replication was assumed to destroy latently infected cells and thereby inhibit tumorigenesis, but at least the initiation of the lytic cycle has now been shown to support EBV-driven malignancies. In addition to these changes in the roles of latent and lytic EBV proteins during tumorigenesis, the function of non-coding RNAs has become clearer, suggesting that they might mainly mediate immune escape rather than cellular transformation. In this Review, these recent findings will be discussed with respect to the role of EBV-encoded oncogenes in viral persistence and the contributions of lytic replication as well as non-coding RNAs in virus-driven tumour formation. Accordingly, early lytic EBV antigens and attenuated viruses without oncogenes and microRNAs could be harnessed for immunotherapies and vaccination.

Immunotherapeutic approaches in nasopharyngeal carcinoma

Introduction: Nasopharyngeal carcinoma (NPC) is endemic in Southern China and Southeast Asia. Epstein-Barr virus (EBV) represents a unique etiological culprit in the poorly differentiated nonkeratinizing and undifferentiated subtypes. EBV antigens are expressed on tumor cells albeit in a restricted manner. Treatment options for recurrent or metastatic disease are limited. Nevertheless, emerging data from immunotherapy studies in NPC have shed light into their potential antitumor efficacy. Areas covered: This article reviews existing clinical evidence for different immunotherapeutic approaches for NPC, including adoptive cellular therapy, therapeutic cancer vaccines, and immune checkpoint inhibitors. Expert opinion: There is a growing understanding on EBV virology and the immune evasion mechanisms in NPC. Immunotherapeutic strategies leveraging these properties have shown encouraging efficacy and safety results in early-phase clinical studies. Moving forward, areas to be addressed include appropriate patient selection, optimal incorporation into standard treatment paradigms, biomarker identification, as well as the development of scalable and reproducible immune product generation processes.

microRNA-613 exerts anti-angiogenic effect on nasopharyngeal carcinoma cells through inactivating the AKT signaling pathway by down-regulating FN1

Background: Nasopharyngeal carcinoma (NPC) is a disease highly sensitive to radiotherapy with the unclear etiology. However, the specific effects of microRNA-613 (miR-613) on NPC still remain elusive. Therefore, the present study probes into the underlying mechanism of miR-613 in NPC via AKT signaling pathway by regulating Fibronectin 1 (FN1).

Methods: First, microarray analysis was used to screen differentially expressed genes (DEGs) and regulatory miRs associated with NPC. Next, miR-613 and FN1 expression in NPC cells was determined, followed by verification of target relationship between miR-613 and FN1. With NPC cells exposed to miR-613 mimic, si-FN1 and LY294002 (inhibitor of AKT signaling pathway), the regulatory effects of miR-613 on proliferation, apoptosis, invasion, migration and angiogenesis of NPC cells were detected with ratio of B-cell lymphoma 2/Bcl-2-associated X protein (Bcl-2/Bax), Cleaved-caspase3, matrix metallopeptidase 2 (MMP-2), MMP-9, vascular endothelial growth factor (VEGF), and cell adhesion molecule-1 (CD31) expression measured. Then, tumorigenesis and MVD were determined after Xenograft in nude mice.

Results: FN1 modulated by miR-613 was critical for NPC via the AKT signaling pathway. NPC cells exhibited down-regulated miR-613 and up-regulated FN1. Besides, miR-613 was verified to target FN1. Moreover, overexpressed miR-613, silenced FN1 or LY294002 treatment suppressed proliferation, invasion, migration, and angiogenesis in NPC cells, which was indicated by reduced expression of AKT, mTOR, MMP-2, MMP-9, VEGF, and CD31 as well as decreased ratio of Bcl-2/Bax and increased expression of Cleaved-caspase3. Furthermore, cell apoptosis was promoted and tumorigenesis and MVD in nude mice were inhibited with overexpression of miR-613, silenced FN1 or LY294002 treatment.

Conclusion: Taken together, miR-613 inhibits angiogenesis in NPC cells through inactivating FN1-dependent AKT signaling pathway.