Targeting the signaling in Epstein-Barr virus-associated diseases: mechanism, regulation, and clinical study

Epstein-Barr virus-driven metabolic alterations contribute to the viral lytic reactivation and tumor progression in nasopharyngeal carcinoma

Metabolic reprogramming induced by Epstein-Barr virus (EBV) often mirrors metabolic changes observed in cancer cells. Accumulating evidence suggests that lytic reactivation is crucial in EBV-associated oncogenesis. The aim of this study was to explore the role of metabolite changes in EBV-associated malignancies and viral life cycle control. We first revealed that EBV (LMP1) accelerates the secretion of the oncometabolite D-2HG, and serum D-2HG level is a potential diagnostic biomarker for NPC. EBV (LMP1)-driven metabolite changes disrupts the homeostasis of global DNA methylation and demethylation, which have a significantly inhibitory effect on active DNA demethylation and 5hmC content. We found that loss of 5hmC indicates a poor prognosis for NPC patients, and that 5hmC modification is a restriction factor of EBV reactivation. We confirmed a novel EBV reactivation inhibitor, α-KG, which inhibits the expression of EBV lytic genes with CpG-containing ZREs and the latent-lytic switch by enhancing 5hmC modification. Our results demonstrate a novel mechanism of which metabolite abnormality driven by EBV controls the viral lytic reactivation through epigenetic modification. This study presents a potential strategy for blocking EBV reactivation, and provides potential targets for the diagnosis and therapy of NPC.

Deciphering the Role of Epstein-Barr Virus Latent Membrane Protein 1 in Immune Modulation: A Multifaced Signalling Perspective

The disruption of antiviral sensors and the evasion of immune defences by various tactics are hallmarks of EBV infection. One of the EBV latent gene products, LMP1, was shown to induce the activation of signalling pathways, such as NF-κB, MAPK (JNK, ERK1/2, p38), JAK/STAT and PI3K/Akt, via three subdomains of its C-terminal domain, regulating the expression of several cytokines responsible for modulation of the immune response and therefore promoting viral persistence. The aim of this review is to summarise the current knowledge on the EBV-mediated induction of immunomodulatory molecules by the activation of signal transduction pathways with a particular focus on LMP1-mediated mechanisms. A more detailed understanding of the cytokine biology molecular landscape in EBV infections could contribute to the more complete understanding of diseases associated with this virus.

Epstein-Barr Virus Latent Membrane Protein 2A (LMP2A) Enhances ATP Production in B Cell Tumors through mTOR and HIF-1α

Epstein-Barr Virus (EBV) exists in a latent state in 90% of the world's population and is linked to numerous cancers, such as Burkitt's Lymphoma, Hodgkin's, and non-Hodgkin's Lymphoma. One EBV latency protein, latency membrane protein 2A (LMP2A), is expressed in multiple latency phenotypes. LMP2A signaling has been extensively studied and one target of LMP2A is the mammalian target of rapamycin (mTOR). Since mTOR has been linked to reprogramming tumor metabolism and increasing levels of hypoxia-inducible factor 1 α (HIF-1α), we hypothesized that LMP2A would increase HIF-1α levels to enhance ATP generation in B lymphoma cell lines. Our data indicate that LMP2A increases ATP generation in multiple Burkitt lymphoma cell lines that were dependent on HIF-1α. Subsequent studies indicate that the addition of the mTOR inhibitor, rapamycin, blocked the LMP2A-dependent increase in HIF-1α. Further studies demonstrate that LMP2A does not increase HIF-1α levels by increasing HIF-1α RNA or STAT3 activation. In contrast, LMP2A and mTOR-dependent increase in HIF-1α required mTOR-dependent phosphorylation of p70 S6 Kinase and 4E-BP1. These findings implicate the importance of LMP2A in promoting B cell lymphoma survival by increasing ATP generation and identifying potential pharmaceutical targets to treat EBV-associated tumors.

Epstein-Barr Virus Infection-Associated Facial Swelling: A Case Report

Maxillofacial soft tissue swelling is a common clinical symptom with various etiologies. While odontogenic space infection is the most common cause, it is crucial not to overlook maxillofacial swellings caused by specific pathogenic infections and other local factors. This paper reports the case of an adult patient with right-sided swelling of his face, persistent oral mucosal ulcers, and recurrent hyperthermia for 30 days. He had received various antibiotics for the initial diagnosis of "right buccal space infection," but the antibiotics did not have any effect on his symptoms. None of the blood tests, histological examinations, bone marrow biopsies, and immune-related tests produced diagnostic findings. A diagnosis of Epstein-Barr virus (EBV) infection was finally confirmed by biopsy tissue genomics sequencing and quantitative analysis of EBV nucleic acid. In this report, we describe the diagnosis and treatment process for this patient and suggest that facial swelling could be an important clinical symptom of EBV infection.

Crosstalk between ubiquitin ligases and ncRNAs drives cardiovascular disease progression

Cardiovascular diseases (CVDs) are multifactorial chronic diseases and have the highest rates of morbidity and mortality worldwide. The ubiquitin-proteasome system (UPS) plays a crucial role in posttranslational modification and quality control of proteins, maintaining intracellular homeostasis via degradation of misfolded, short-lived, or nonfunctional regulatory proteins. Noncoding RNAs (ncRNAs, such as microRNAs, long noncoding RNAs, circular RNAs and small interfering RNAs) serve as epigenetic factors and directly or indirectly participate in various physiological and pathological processes. NcRNAs that regulate ubiquitination or are regulated by the UPS are involved in the execution of target protein stability. The cross-linked relationship between the UPS, ncRNAs and CVDs has drawn researchers' attention. Herein, we provide an update on recent developments and perspectives on how the crosstalk of the UPS and ncRNAs affects the pathological mechanisms of CVDs, particularly myocardial ischemia/reperfusion injury, myocardial infarction, cardiomyopathy, heart failure, atherosclerosis, hypertension, and ischemic stroke. In addition, we further envision that RNA interference or ncRNA mimics or inhibitors targeting the UPS can potentially be used as therapeutic tools and strategies.

Epstein-Barr virus: the mastermind of immune chaos

The Epstein-Barr virus (EBV) is a ubiquitous human pathogen linked to various diseases, including infectious mononucleosis and multiple types of cancer. To control and eliminate EBV, the host's immune system deploys its most potent defenses, including pattern recognition receptors, Natural Killer cells, CD8+ and CD4+ T cells, among others. The interaction between EBV and the human immune system is complex and multifaceted. EBV employs a variety of strategies to evade detection and elimination by both the innate and adaptive immune systems. This demonstrates EBV's mastery of navigating the complexities of the immunological landscape. Further investigation into these complex mechanisms is imperative to advance the development of enhanced therapeutic approaches with heightened efficacy. This review provides a comprehensive overview of various mechanisms known to date, employed by the EBV to elude the immune response, while establishing enduring latent infections or instigate its lytic replication.

Epstein-Barr Virus Promotes Tumorigenicity and Worsens Hodgkin Lymphoma Prognosis by Activating JAK/STAT and NF-κB Signaling Pathways

Background

Epstein-Barr virus (EBV) is detected in 40% of patients with Hodgkin lymphoma (HL). During latency, EBV induces epigenetic alterations to the host genome and decreases the expression of pro-apoptotic proteins. The present study aimed to evaluate the expression levels of mRNA molecules and the end product of proteins for the JAK/STAT and NF-κB pathways, and their association with clinicopathological and prognostic parameters in patients with EBV-positive and -negative classical Hodgkin lymphoma (CHL).

Methods

A prospective cohort study was conducted from 2017 to 2022 at the Faculty of Medicine, Zagazig University Hospital (Zagazig, Egypt). Biopsy samples of 64 patients with CHL were divided into EBV-positive and EBV-negative groups. The expression levels of mRNA molecules (JAK2, STAT1, IRF-1, PD-L1, IFN-γ, NF-κB, Bcl-xL, COX-2) and the end product of proteins (PD-L1, Bcl-xL, COX-2) were determined and compared with clinicopathological and prognostic parameters. Data were analyzed using the Chi square test and Kaplan-Meier estimate.

Results

EBV-positive CHL patients were significantly associated with positive expression of mRNAs molecules (P<0.001) and the end product of proteins (P<0.001) for the JAK/STAT and NF-κB pathways, B-symptoms (P=0.022), extra-nodal involvement (P=0.017), and advanced stage of CHL (P=0.018). These patients were more susceptible to cancer progression, higher incidence of relapse (P=0.008), poor disease-free survival rate (P=0.013), poor overall survival rate (P=0.028), and higher mortality rate (P=0.015).

Conclusion

Through the activation of JAK/STAT and NF-κB signaling pathways, EBV-positive CHL is associated with poor clinicopathological parameters, higher incidence of disease progression, relapse, and poor overall survival. A preprint of this manuscript is available on research square (doi: 10.21203/rs.3.rs-1857436/v1).

CYLD induces high oxidative stress and DNA damage through class I HDACs to promote radiosensitivity in nasopharyngeal carcinoma

Abnormal expression of Cylindromatosis (CYLD), a tumor suppressor molecule, plays an important role in tumor development and treatment. In this work, we found that CYLD binds to class I histone deacetylases (HDAC1 and HDAC2) through its N-terminal domain and inhibits HDAC1 activity. RNA sequencing showed that CYLD-HDAC axis regulates cellular antioxidant response via Nrf2 and its target genes. Then we revealed a mechanism that class I HDACs mediate redox abnormalities in CYLD low-expressing tumors. HDACs are central players in the DNA damage signaling. We further confirmed that CYLD regulates radiation-induced DNA damage and repair response through inhibiting class I HDACs. Furthermore, CYLD mediates nasopharyngeal carcinoma cell radiosensitivity through class I HDACs. Thus, we identified the function of the CYLD-HDAC axis in radiotherapy and blocking HDACs by Chidamide can increase the sensitivity of cancer cells and tumors to radiation therapy both in vitro and in vivo. In addition, ChIP and luciferase reporter assays revealed that CYLD could be transcriptionally regulated by zinc finger protein 202 (ZNF202). Our findings offer novel insight into the function of CYLD in tumor and uncover important roles for CYLD-HDAC axis in radiosensitivity, which provide new molecular target and therapeutic strategy for tumor radiotherapy.

Serum Anti-Zta and Anti-LMP1 Antibodies in Oropharyngeal Cancer Related to Epstein-Barr Virus-Diagnostic Usefulness

BACKGROUND

The role of the Epstein-Barr virus (EBV), the first known human oncogenic virus, in the development of nasopharyngeal cancer (NPC) is already well documented. There are few studies in the available scientific literature on oropharyngeal cancer associated with EBV infection. Due to the lack of an effective vaccine against EBV, it is necessary to search for new markers for the early diagnosis and prognosis of this disease. The aim of current study was to determine the usefulness of anti-Zta and anti-LMP1 antibodies as diagnostic and prognostic markers in EBV positive OPSCC patients.

METHODS

For this purpose, experiments were carried out to determine both the prevalence and level of EBVCA, EBNA1, EA, Zta, and LMP1 antibodies in serum patients depending on histological differentiation-grading and TNM classification (ELISA assay).

RESULTS

Based on the obtained results, we showed that OPSCC EBV positive patients are characterized by a higher level of anti-Zta antibodies than in the EBV negative group. Their level depended on the clinical stage. Moreover, a ROC analysis confirmed the diagnostic accuracy of anti-Zta antibodies.

CONCLUSIONS

Anti-Zta and anti-LMP1 antibodies may be useful in the diagnosis of OPSCC. It seems that combined antibody testing should be performed to increase diagnostic accuracy.

The master antioxidant defense is activated during EBV latent infection

IMPORTANCE

To our knowledge, this is the first report delineating the activation of the master antioxidant defense during EBV latency. We show that EBV-triggered reactive oxygen species production activates the Keap1-NRF2 pathway in EBV-transformed cells, and LMP1 plays a major role in this event, and the stress-related kinase TBK1 is required for NRF2 activation. Moreover, we show that the Keap1-NRF2 pathway is important for cell proliferation and EBV latency maintenance. Our findings disclose how EBV controls the balance between oxidative stress and antioxidant defense, which greatly improve our understanding of EBV latency and pathogenesis and may be leveraged to opportunities toward the improvement of therapeutic outcomes in EBV-associated diseases.

Non-overlapping epitopes on the gHgL-gp42 complex for the rational design of a triple-antibody cocktail against EBV infection

Epstein-Barr virus (EBV) is closely associated with cancer, multiple sclerosis, and post-acute coronavirus disease 2019 (COVID-19) sequelae. There are currently no approved therapeutics or vaccines against EBV. It is noteworthy that combining multiple EBV glycoproteins can elicit potent neutralizing antibodies (nAbs) against viral infection, suggesting possible synergistic effects. Here, we characterize three nAbs (anti-gp42 5E3, anti-gHgL 6H2, and anti-gHgL 10E4) targeting different glycoproteins of the gHgL-gp42 complex. Two antibody cocktails synergistically neutralize infection in B cells (5E3+6H2+10E4) and epithelial cells (6H2+10E4) in vitro. Moreover, 5E3 alone and the 5E3+6H2+10E4 cocktail confer potent in vivo protection against lethal EBV challenge in humanized mice. The cryo-EM structure of a heptatomic gHgL-gp42 immune complex reveals non-overlapping epitopes of 5E3, 6H2, and 10E4 on the gHgL-gp42 complex. Structural and functional analyses highlight different neutralization mechanisms for each of the three nAbs. In summary, our results provide insight for the rational design of therapeutics or vaccines against EBV infection.

Epidemiological Profile of Salivary Gland Tumors in Southern Iranian Population: A Retrospective Study of 405 Cases

Aims

Salivary gland tumors (SGTs) are a rare and diverse group of tumors that account for 3 to 10% of all head and neck malignancies. We aimed to conduct a comprehensive epidemiological analysis of SGTs in the south of Iran and compare the findings with previous reports from Iran and other parts of the world.

Methods

Using a retrospective study, 405 patients diagnosed with SGTs were observed over an eight-year period between April 2013 and October 2021 in Shiraz, Iran. Patients' demographic and clinicopathological features were obtained from patients' records. Quantitative and descriptive data analysis was performed using SPSS software.

Results

There were 302 benign (74.5%) and 103 (25.4%) malignant SGTs. Pleomorphic adenoma and Warthin's tumors were the most common benign SGTs (70.5% and 21.5%, respectively). The most common malignant SGTs were mucoepidermoid carcinoma and adenoid cystic carcinoma (26.2% and 22.3%, respectively). There was a statistically significant association between tumor origin and its malignancy status (p < 0.001). In addition, the results indicated that benign tumors were most commonly detected in the parotid gland (p < 0.05). The benign tumors were more frequently observed among the younger population (p = 0.006).

Conclusion

In summary, the findings of the current study were mainly consistent with the previous reports from Iran and the rest of the world. Benign tumors were the most prevalent type of SGTs, and the parotid gland was the most common site. While the majority of cases that developed from the major salivary glands were benign, all the minor SGTs were malignant. Older patients were more likely to develop malignant tumors compared to younger ones. This study provides insights into the prevalence, age-related incidence, gender distribution, and geographic variation of salivary gland tumors. This can be instrumental to develop a guideline for screening, diagnosis, and determining an optimal treatment.

Preparation of monoclonal antibodies against Epstein-Barr virus glycoprotein 350

Epstein-Barr virus (EBV) is the first identified human oncogenic herpesvirus infecting over 90% of the adults worldwide. However, the safe and effective prophylactic vaccine has not been licensed. The major glycoprotein 350 (gp350) on the EBV envelope is the main target for neutralizing antibodies, and gp350 (aa15-320) was used for the development of monoclonal antibodies in present study. The purified recombinant gp35015-320aa with an estimated molecular weight of 50 kDa was used to immunize six-week-old BALB/c mice, and the hybridoma cell lines that stably secreted monoclonal antibodies (mAbs) were obtained. The ability of developed mAbs for capturing and neutralizing EBV was evaluated, and mAb 4E1 presented better performance to block the infection of EBV in cell line Hone-1. The mAb 4E1 recognized the epitope. Its sequence of variable region genes (VH and VL) presented a unique identity which hadn't been reported. The developed mAbs might benefit the antiviral therapy and immunologic diagnosis for EBV infection.

Sintilimab treatment for chronic active Epstein-Barr virus infection and Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis in children

BACKGROUND

Chronic active Epstein-Barr virus infection (CAEBV) and Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) are rare but life-threatening progressive diseases triggered by EBV infection. Glucocorticoid/immunosuppressants treatment is temporarily effective; however, most patients relapse and/or progress. Hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy; however, there are risks of transplantation-associated complications. Currently there is no standard treatment for CAEBV and EBV-HLH. Programmed death protein 1 (PD-1) inhibitors have achieved a high response in many EBV-related diseases. Sintilimab (a recombinant human IgG4 monoclonal antibody against PD-1) disrupts the interaction between PD-1 and its ligand, leading to T cell reinvigoration.

METHODS

A retrospective analysis was performed on three children with CAEBV or EBV-HLH in the Children's Hospital of Soochow University between 12 December 2020 and 28 November 2022. The efficacy of sintilimab was evaluated.

RESULTS

Three patients, including two males and one female, were analyzed. Among them, two children were diagnosed with CAEBV with intermittent fever for more than four years, and one child was diagnosed with EBV-HLH. After sintilimab treatment and a mean follow-up of 17.1 months (range 10.0-23.3 months), patients 1 and 3 achieved a complete clinical response and patient 2 achieved a partial clinical response. All three children showed a > 50% decrease in EBV-DNA load in both blood and plasma. EBV-DNA copies in sorted T, B, and NK cells were also markedly decreased after sintilimab treatment.

CONCLUSION

Our data supported the efficacy of PD-1 targeted therapy in certain patients with CAEBV and EBV-HLH, and suggested that sintilimab could provide a cure for these diseases, without HSCT. More prospective studies and longer follow-up are needed to confirm these conclusions.

Distribution of Epstein-Barr Virus LMP1 Variants in Patients with Infectious Mononucleosis and Association with Selected Biochemical and Hematological Parameters

The molecular diversity of Epstein-Barr virus (EBV) is exceptionally complex and based on the characterization of sequences coding for several viral genes. The aim of this study was to analyze the distribution of EBV types 1 and 2 and to characterize LMP1 variants in a cohort of 73 patients with infectious mononucleosis (IM), as well as to investigate a possible association between viral diversity and relevant clinical parameters. Population-based sequencing of EBNA-2 gene showed the presence of EBV type 1 in all IM patients. Analysis of LMP1 gene found a restricted repertoire of LMP1 variants with the predominance of wild-type B95-8, China1, Mediterranean and North Carolina variants with the presence of more than one LMP1 variant in 16.4% of patients. Co-infections with different LMP1 variants were associated with significantly higher levels of C-reactive protein and lower levels of maximal neutrophil counts and minimal platelet count. The results of this study have shown a narrow repertoire of LMP1 variants and an exclusive presence of EBV type 1 in a cohort of IM from Croatia, suggesting a characteristic local molecular pattern of this virus. The clinical importance of distinct immunobiological features of IM patients with LMP1 variant co-infections needs to be investigated further.

Infectious agents and pathogenesis of Behçet's disease: An extensive review

Behçet's disease (BD) is a multisystemic chronic vasculitis. Sustained and enhanced immune responses were reportedly associated with active BD. Although genetic polymorphisms increase development risk, genetic factors alone cannot account for BD development, suggesting the involvement of exogenous factors. Also, how various infectious agents promote BD in high-risk populations is not fully understood. In this review, we summarized the current findings on the associations of infectious agents with BD pathogenesis. The review also highlights the potential microbial risk factors and their pathogenic role in BD progression. Interactions between genetic and infectious risk factors was also discussed. Furthermore, evidence implied that after the eradication of infectious agents, BD symptoms and recurrence decreased, thus highlighting that combined use of antibiotics may be an effective therapy for BD. Finally, we summarized the main limitation of the current related studies, providing valuable insights and a basis for future studies on BD pathogenic factors.

Attenuation of IFN signaling due to m6A modification of the host epitranscriptome promotes EBV lytic reactivation

BACKGROUND

Reactivation of Epstein Barr virus (EBV) leads to modulation of the viral and cellular epitranscriptome. N6-methyladenosine (m6A) modification is a type of RNA modification that regulates metabolism of mRNAs. Previous reports demonstrated that m6A modification affects the stability and metabolism of EBV encoded mRNAs. However, the effect of reactivation on reprograming of the cellular mRNAs, and how this contributes to successful induction of lytic reactivation is not known.

METHODS

Methylated RNA immunoprecipitation sequencing (MeRIP-seq), transcriptomic RNA sequencing (RNA-seq) and RNA pull-down PCR were used to screen and validate differentially methylated targets. Western blotting, quantitative real-time PCR (RT-qPCR) and immunocytochemistry were used to investigate the expression and localization of different proteins. RNA stability and polysome analysis assays were used to detect the half-lives and translation efficiencies of downstream genes. Insertion of point mutation to disrupt the m6A methylation sites was used to verify the effect of m6A methylation on its stability and expression levels.

RESULTS

We report that during EBV reactivation the m6A eraser ALKBH5 is significantly downregulated leading to enhanced methylation of the cellular transcripts DTX4 and TYK2, that results in degradation of TYK2 mRNAs and higher efficiency of translation of DTX4 mRNAs. This resulted in attenuation of IFN signaling that promoted progression of viral lytic replication. Furthermore, inhibition of m6A methylation of these transcripts led to increased production of IFN, and a substantial reduction in viral copy number, which suggests abrogation of lytic viral replication.

CONCLUSION

Our findings illuminate the significance of m6A modification in overcoming the innate immune response during EBV reactivation. We now report that during lytic reactivation EBV targets the RNA methylation system of the host to attenuate the innate immune response by suppressing the interferon signaling which facilitates successful lytic replication of the virus.

Tumor resident, TRA anti-viral CDR3 chemical sequence motifs are associated with a better breast cancer outcome

While for certain cancers, such as cervical cancer, the link to viral infections is very strong and very clear, other cancers represent a history of links to viral infections that are either co-morbidities or drive the cancer in ways that are not yet fully understood, for example the "hit and run" possibility. To further understand the connection of viral infections and the progress of breast cancer, we identified the chemical features of known anti-viral, T-cell receptor alpha chain (TRA) complementarity determining region-3 (CDR3) amino acid sequences among the CDR3s of breast cancer patient TRA recombinations and assessed the association of those features with patient outcomes. The application of this novel paradigm indicated consistent associations of tumor-derived, anti-CMV CDR3 chemical sequence motifs with better breast cancer patient outcomes but did not indicate an opportunity to establish risk stratifications for other cancer types. Interestingly, breast cancer samples with no detectable TRA recombinations represented a better outcome than samples with the non-anti-CMV CDR3s, further adding to a rapidly developing series of results allowing a distinction between positive and possibly harmful cancer immune responses.

A New Insight Into p53-Inhibiting Genes in Epstein–Barr Virus-Associated Gastric Adenocarcinoma

Background

The p53 mutation is uncommon in Epstein–Barr virus-linked gastric carcinoma, but its suppression occurs through mechanisms such as ubiquitin specific peptidase 7 (USP7) inhibitions via Epstein–Barr virus nuclear antigen-1 (EBNA1) activity. This study aimed to evaluate the effect of EBNA1 on p53-inhibiting gene expression and the impact of USP7 inhibition on p53 suppression.

Methods

MKN-45 cells were transfected with the EBNA1 plasmid. A stable EBNA1 expression cell line was developed through selection based on hygromycin B resistance. Murine double minute (MDM)4, MDM2, sirtuin (SIRT)3, histone deacetylase (HDAC)1, proteasome 26S subunit, Non-ATPase (PSMD)10, USP7, and p53 expression were checked using real-time PCR. Also, cells containing EBNA1 or control plasmid were treated with GNE-6776, and the expression of the interested genes and cell survival were assessed.

Results

MDM4, MDM2, and PSMD10 were significantly upregulated in the MKN-45 cell line following EBNA1 transfection. Morphological changes were observed in the cells harboring EBNA1 after 20 days. In the control cells, USP7 inhibition significantly upregulated the HDAC1, PSMD10, MDM4, and MDM2 genes after 24 h, but downregulated these genes after four days. In the EBNA1-harboring cells, MDM2, MDM4, and PSMD10 genes were significantly upregulated after 24 h, and this effect was sustained for all genes except for MDM4, even after four days. Furthermore, USP7 inhibition induced apoptosis in both cell groups.

Conclusion

EBNA1 enhances the expression of p53-inhibiting genes. Two events—p53 protein overexpression and apoptosis activation—followed the suppression of the USP7 protein and provided evidence for its possible function. The significance of the EBNA1-USP7 interaction in p53 suppression warrants additional investigation and possibly reconsideration.

An Update on the Metabolic Landscape of Oncogenic Viruses

Viruses play an important role in cancer development as about 12% of cancer types are linked to viral infections. Viruses that induce cellular transformation are known as oncoviruses. Although the mechanisms of viral oncogenesis differ between viruses, all oncogenic viruses share the ability to establish persistent chronic infections with no obvious symptoms for years. During these prolonged infections, oncogenic viruses manipulate cell signaling pathways that control cell cycle progression, apoptosis, inflammation, and metabolism. Importantly, it seems that most oncoviruses depend on these changes for their persistence and amplification. Metabolic changes induced by oncoviruses share many common features with cancer metabolism. Indeed, viruses, like proliferating cancer cells, require increased biosynthetic precursors for virion production, need to balance cellular redox homeostasis, and need to ensure host cell survival in a given tissue microenvironment. Thus, like for cancer cells, viral replication and persistence of infected cells frequently depend on metabolic changes. Here, we draw parallels between metabolic changes observed in cancers or induced by oncoviruses, with a focus on pathways involved in the regulation of glucose, lipid, and amino acids. We describe whether and how oncoviruses depend on metabolic changes, with the perspective of targeting them for antiviral and onco-therapeutic approaches in the context of viral infections.

Self-Assembling Protein Nanoparticles in the Design of Vaccines: 2022 Update

Vaccines constitute a pillar in the prevention of infectious diseases. The unprecedented emergence of novel immunization strategies due to the COVID-19 pandemic has again positioned vaccination as a pivotal measure to protect humankind and reduce the clinical impact and socioeconomic burden worldwide. Vaccination pursues the ultimate goal of eliciting a protective response in immunized individuals. To achieve this, immunogens must be efficiently delivered to prime the immune system and produce robust protection. Given their safety, immunogenicity, and flexibility to display varied and native epitopes, self-assembling protein nanoparticles represent one of the most promising immunogen delivery platforms. Currently marketed vaccines against the human papillomavirus, for instance, illustrate the potential of these nanoassemblies. This review is intended to provide novelties, since 2015, on the ground of vaccine design and self-assembling protein nanoparticles, as well as a comparison with the current emergence of mRNA-based vaccines.

Hypermethylation of PRKCZ Regulated by E6 Inhibits Invasion and EMT via Cdc42 in HPV-Related Head and Neck Squamous Cell Carcinoma

Purpose: To study the role of target genes with aberrant DNA methylation in HPV+ HNSCC. Methods: A HumanMethylation450 BeadChip array (Illumina) was used to identify differentially methylated genes. CCK-8, flow cytometry, wound healing, and cell invasion assays were conducted to analyze the biological roles of PRKCZ. Western blot, qRT-PCR, immunohistochemistry, and animal studies were performed to explore the mechanisms underlying the functions of PRKCZ. Results: We selected PRKCZ, which is associated with HPV infection, as our target gene. PRKCZ was hypermethylated in HPV+ HNSCC patients, and PRKCZ methylation status was negatively related to the pathological grading of HNSCC patients. Silencing PRKCZ inhibited the malignant capacity of HPV+ HNSCC cells. Mechanistically, HPV might promote DNMT1 expression via E6 to increase PRKCZ methylation. Cdc42 was required for the PRKCZ-mediated mechanism of action, contributing to the occurrence of epithelial-mesenchymal transition (EMT) in HPV+ HNSCC cells. In addition, blocking PRKCZ delayed tumor growth in HPV16-E6/E7 transgenic mice. Cdc42 expression was decreased, whereas E-cadherin levels increased. Conclusion: We suggest that PRKCZ hypermethylation induces EMT via Cdc42 to act as a potent tumor promoter in HPV+ HNSCC.

Phase separation in Cancer: From the Impacts and Mechanisms to Treatment potentials

Cancer is a public health problem of great concern, and it is also one of the main causes of death in the world. Cancer is a disease characterized by dysregulation of diverse cellular processes, including avoiding growth inhibitory factors, avoiding immune damage and promoting metastasis, etc. However, the precise mechanism of tumorigenesis and tumor progression still needs to be further elucidated. Formations of liquid-liquid phase separation (LLPS) condensates are a common strategy for cells to achieve diverse functions, such as chromatin organization, signal transduction, DNA repair and transcriptional regulation, etc. The biomolecular aggregates formed by LLPS are mainly driven by multivalent weak interactions mediated by intrinsic disordered regions (IDRs) in proteins. In recent years, aberrant phase separations and transition have been reported to be related to the process of various diseases, such as neurodegenerative diseases and cancer. Herein, we discussed recent findings that phase separation regulates tumor-related signaling pathways and thus contributes to tumor progression. We also reviewed some tumor virus-associated proteins to regulate the development of virus-associated tumors via phase separation. Finally, we discussed some possible strategies for treating tumors by targeting phase separation.

Progress in Prophylactic and Therapeutic EBV Vaccine Development Based on Molecular Characteristics of EBV Target Antigens

Epstein–Barr virus (EBV) was discovered in 1964 in the cell line of Burkitt lymphoma and became first known human oncogenic virus. EBV belongs to the Herpesviridae family, and is present worldwide as it infects 95% of people. Infection with EBV usually happens during childhood when it remains asymptomatic; however, in adults, it can cause an acute infection known as infectious mononucleosis. In addition, EBV can cause wide range of tumors with origins in B lymphocytes, T lymphocytes, and NK cells. Its oncogenicity and wide distribution indicated the need for vaccine development. Research on mice and cultured cells as well as human clinical trials have been in progress for a few decades for both prophylactic and therapeutic EBV vaccines. The main targets of the vaccines are EBV envelope glycoproteins such as gp350 and EBV latent genes. The long wait for the EBV vaccine is due to the complexity of the EBV replication cycle and the wide range of its host cells. Although some strategies such as the use of dendritic cells and recombinant Vaccinia viral vectors have shown success, ongoing clinical trials using mRNA-based vaccines as well as new delivery systems as nanoparticles are yet to show the best choice of vaccine target and its production strategy.

Glycoprotein B Antibodies Completely Neutralize EBV Infection of B Cells

The Epstein–Barr virus (EBV) is the first reported oncogenic herpesvirus that establishes persistent infection in B lymphocytes in 95% of adults worldwide. Glycoprotein B (gB) plays a predominant role in the fusion of the viral envelope with the host cell membrane. Hence, it is of great significance to isolate gB-specific fusion-inhibiting neutralizing antibodies (NAbs). AMMO5 is the only gB NAb but fails to antagonize B-cell infection. It is essential to isolate potent NAbs that can completely block EBV infection of B cells. Using hybridoma technology and neutralization assay, we isolate two gB NAbs 8A9 and 8C12 that are capable of completely neutralizing B-cell infection in vitro. In addition, 8A9 shows cross-reactivity with rhesus lymphocryptovirus (rhLCV) gB. Competitive binding experiments demonstrate that 8A9 and 8C12 recognize novel epitopes that are different from the AMMO5 epitope. The epitopes of 8A9 and 8C12 are mapped to gB D-II, and the AMMO5 epitope is located precisely at gB aa 410–419. We find that 8A9 and 8C12 significantly inhibit gB-derived membrane fusion using a virus-free fusion assay. In summary, this study identifies two gB-specific NAbs that potently block EBV infection of B cells. Our work highlights the importance of gB D-II as a predominant neutralizing epitope, and aids in the rational design of therapeutics or vaccines based on gB.

Clinical features and prognosis of acute lymphoblastic leukemia in children with Epstein-Barr virus infection

BACKGROUND

Acute lymphoblastic leukemia (ALL) is one of the most common malignant diseases of the hematopoietic system in children. Although the etiology of ALL is unknown, it has been reported that it may be associated with Epstein-Barr virus (EBV) infection. The aim of this study was to analyze the impact of EBV infection on the clinical features and prognosis of childhood ALL.

METHODS

A total of 162 children with ALL admitted to Heilongjiang Provincial Hospital from January 2018 to December 2020 were selected for this stud, and were divided into 2 groups, infected group and non-infected group, according to whether they had EBV infection. Differences in clinical characteristics between the 2 groups were analyzed by χ² or t-test. The impact of EBV infection on the prognosis of children was analyzed by Kaplan-Meier survival and Cox regression analysis.

RESULTS

The 2 groups were statistically significantly different (P<0.05) according to comparison of characteristics such as first symptoms, karyotype, immunophenotyping, clinical risk, whether secondary infection occurred during chemotherapy, and lymphocyte subsets. Logistic regression results suggested that first symptoms, karyotype, immunophenotyping, clinical risk, the presence of secondary infection during chemotherapy, and lymphocyte subsets were independently associated with EBV infection in children with ALL (P<0.05). The complete remission rate at 46 days after chemotherapy, event-free survival (EFS), overall survival (OS), and survival rate were lower in the infected group than non-infected group, and the complete remission recurrence rate was higher than non-infected group (P<0.05). The EBV DNA levels were statistically lower in the good prognosis group (1.07±0.25×10³ copies/L) than poor prognosis group (8.86±1.14 ×10³ copies/L) (P<0.01). The area under the curve (AUC) for EBV to predict prognosis in children with ALL was 0.921, sensitivity and sensitivity were 86.57%, 80.16%.

CONCLUSIONS

Infection with EBV is associated with first symptoms, karyotype, immunophenotyping, clinical risk, secondary infection during chemotherapy, and lymphocyte subpopulation index levels in children with ALL, and children with EBV infection have a reduced clinical remission rate and poor prognosis. Therefore, the detection of EBV DNA is clinically important for assessing the prognosis of their disease.

In-situ scalable manufacturing of Epstein-Barr virus-specific T-cells using bioreactor with an expandable culture area (BECA)

The ex-vivo expansion of antigen-specific T-cells for adoptive T-cell immunotherapy requires active interaction between T-cells and antigen-presenting cells therefore culture density and environment become important variables to control. Maintenance of culture density in a static environment is traditionally performed by the expansion of the culture area through splitting of culture from a single vessel into multiple vessels-a highly laborious process. This study aims to validate the use and efficacy of a novel bioreactor, bioreactor with an expandable culture area-dual chamber (BECA-D), that was designed and developed with a cell chamber with expandable culture area (12-108 cm²) and a separate media chamber to allow for in-situ scaling of culture with maintenance of optimum culture density and improved nutrient and gas exchange while minimizing disturbance to the culture. The performance of BECA-D in the culture of Epstein-Barr virus-specific T-cells (EBVSTs) was compared to the 24-well plate. BECA-D had 0.9-9.7 times the average culture yield of the 24-well plates across 5 donor sets. BECA-D was able to maintain the culture environment with relatively stable glucose and lactate levels as the culture expanded. This study concludes that BECA-D can support the culture of ex-vivo EBVSTs with lower manufacturing labour and time requirements compared to the use of the 24-well plate. BECA-D and its adaptation into a closed system with an automated platform (currently being developed) provides cell therapy manufacturers and developers with a closed scale-out solution to producing adoptive cell therapy for clinical use.

CPT1A-mediated fatty acid oxidation promotes cell proliferation via nucleoside metabolism in nasopharyngeal carcinoma

As the first rate-limiting enzyme in fatty acid oxidation (FAO), CPT1 plays a significant role in metabolic adaptation in cancer pathogenesis. FAO provides an alternative energy supply for cancer cells and is required for cancer cell survival. Given the high proliferation rate of cancer cells, nucleotide synthesis gains prominence in rapidly proliferating cells. In the present study, we found that CPT1A is a determining factor for the abnormal activation of FAO in nasopharyngeal carcinoma (NPC) cells. CPT1A is highly expressed in NPC cells and biopsies. CPT1A dramatically affects the malignant phenotypes in NPC, including proliferation, anchorage-independent growth, and tumor formation ability in nude mice. Moreover, an increased level of CPT1A promotes core metabolic pathways to generate ATP, inducing equivalents and the main precursors for nucleotide biosynthesis. Knockdown of CPT1A markedly lowers the fraction of ¹³C-palmitate-derived carbons into pyrimidine. Periodic activation of CPT1A increases the content of nucleoside metabolic intermediates promoting cell cycle progression in NPC cells. Targeting CPT1A-mediated FAO hinders the cell cycle G1/S transition. Our work verified that CPT1A links FAO to cell cycle progression in NPC cellular proliferation, which supplements additional experimental evidence for developing a therapeutic mechanism based on manipulating lipid metabolism.

Preclinical efficacy and involvement of mTOR signaling in the mechanism of Orf virus against nasopharyngeal carcinoma cells

AIMS

Orf virus (ORFV) is a parapoxvirus causing contagious ecthyma in sheep and goats. With inhibitory role of ORFV reported by previous studies, ORFV can be a candidate of oncolytic virus. However, few studies reported the application and mechanism of ORFV in nasopharyngeal carcinoma (NPC). We aimed to elucidate the anti-tumor mechanism of ORFV against NPC cells.

MATERIALS AND METHODS

The anti-tumor effect of ORFV in NPC cells was confirmed by cell counting kit 8 (CCK-8) assay, flow cytometry and Western blot. In vitro and in vivo experiments were adopted to evaluate the inhibitory effect of ORFV in NPC cells. Western blot was used to determine the down-regulation of rapamycin (mTOR) signaling and autophagy enhancement induced by ORFV. To explore the mechanism of ORFV on NPC cells, mTOR signaling agonist and autophagy inhibitors were used to rescue the effects of ORFV.

KEY FINDINGS

The results indicated that ORFV replicates in NPC cells, thus induces the apoptosis of NPC cells. Moreover, ORFV can effectively inhibit NPC cell growth in vivo. ORFV infection in NPC cells leads to the mTOR signaling inhibition and up-regulated autophagy, which might be the specific mechanism of ORFV in killing tumor cells. As to safety confirmation, normal nasopharyngeal epithelial cells NP69 are insensitive to ORFV. More importantly, ORFV would not cause organ damage in vivo.

SIGNIFICANCES

Our data clarified that ORFV induces autophagy of NPC cells via inhibiting mTOR signaling, thus further inducing apoptosis. The anti-tumor role of ORFV might provide a preclinical strategy for NPC treatment.

Novel directions of precision oncology: Circulating microbial DNA emerging in cancer-microbiome areas

Microbiome research has extended into the cancer area in the past decades. Microbes can affect oncogenesis, progression, and treatment response through various mechanisms, including direct regulation and indirect impacts. Microbiota-associated detection methods and agents have been developed to facilitate cancer diagnosis and therapy. Additionally, the cancer microbiome has recently been redefined. The identification of intra-tumoral microbes and cancer-related circulating microbial DNA (cmDNA) has promoted novel research in the cancer–microbiome area. In this review, we define the human system of commensal microbes and the cancer microbiome from a brand-new perspective and emphasize the potential value of cmDNA as a promising biomarker in cancer liquid biopsy. We outline all existing studies on the relationship between cmDNA and cancer and the outlook for potential preclinical and clinical applications of cmDNA in cancer precision medicine, as well as critical problems to be overcome in this burgeoning field.

Common DNA methylation changes in biliary tract cancers identify subtypes with different immune characteristics and clinical outcomes

BACKGROUND

DNA methylation-associated studies on biliary tract cancer (BTC), including cholangiocarcinoma (CCA) and gallbladder cancer (GBC), may improve the BTC classification scheme. We proposed to identify the shared methylation changes of BTCs and investigate their associations with genomic aberrations, immune characteristics, and survival outcomes.

METHODS

Multi-dimensional data concerning mutation, DNA methylation, immune-related features, and clinical data of 57 CCAs and 48 GBCs from Eastern Hepatobiliary Surgery Hospital (EHSH) and 36 CCAs in the TCGA-CHOL cohort were analyzed.

RESULTS

In our cohort including 24 intrahepatic CCAs (iCCAs), 20 perihilar CCAs (pCCAs), 13 distal CCAs (dCCAs), and 48 GBCs, 3369 common differentially methylated regions (DMRs) were identified by comparing tumor and non-tumor samples. A lower level of methylation changes of these common DMRs was associated with fewer copy number variations, fewer mutational burden, and remarkably longer overall survival (OS, hazard ratio [HR] = 0.07, 95% confidence interval [CI] 0.01-0.65, P = 0.017). Additionally, a 12-marker model was developed and validated for prognostication after curative surgery (HR = 0.21, 95% CI 0.10-0.43, P < 0.001), which exhibited undifferentiated prognostic effects in subgroups defined by anatomic location (iCCAs, d/pCCAs, GBCs), TNM stage, and tumor purity. Its prognostic utility remained significant in multivariable analysis (HR = 0.26, 95% CI 0.11-0.59, P = 0.001). Moreover, the BTCs with minimal methylation changes exhibited higher immune-related signatures, infiltration of CD8⁺ lymphocytes, and programmed death-ligand 1 (PD-L1) expression, indicating an inflamed tumor immune microenvironment (TIME) with PD-L1 expression elicited by immune attack, potentially suggesting better immunotherapy efficacy.

CONCLUSIONS

In BTCs, DNA methylation is a powerful tool for molecular classification, serving as a robust indicator of genomic aberrations, survival outcomes, and tumor immune microenvironment. Our integrative analysis provides insights into the prognostication after curative surgery and patient selection for immunotherapy.

Functional Roles of JNK and p38 MAPK Signaling in Nasopharyngeal Carcinoma

c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) family members integrate signals that affect proliferation, differentiation, survival, and migration in a cell context- and cell type-specific way. JNK and p38 MAPK activities are found upregulated in nasopharyngeal carcinoma (NPC). Studies have shown that activation of JNK and p38 MAPK signaling can promote NPC oncogenesis by mechanisms within the cancer cells and interactions with the tumor microenvironment. They regulate multiple transcription activities and contribute to tumor-promoting processes, ranging from cell proliferation to apoptosis, inflammation, metastasis, and angiogenesis. Current literature suggests that JNK and p38 MAPK activation may exert pro-tumorigenic functions in NPC, though the underlying mechanisms are not well documented and have yet to be fully explored. Here, we aim to provide a narrative review of JNK and p38 MAPK pathways in human cancers with a primary focus on NPC. We also discuss the potential therapeutic agents that could be used to target JNK and p38 MAPK signaling in NPC, along with perspectives for future works. We aim to inspire future studies further delineating JNK and p38 MAPK signaling in NPC oncogenesis which might offer important insights for better strategies in diagnosis, prognosis, and treatment decision-making in NPC patients.

Nanotechnology Frontiers in γ-Herpesviruses Treatments

Epstein–Barr Virus (EBV) and Kaposi’s sarcoma associated-herpesvirus (KSHV) are γ-herpesviruses that belong to the Herpesviridae family. EBV infections are linked to the onset and progression of several diseases, such as Burkitt lymphoma (BL), nasopharyngeal carcinoma (NPC), and lymphoproliferative malignancies arising in post-transplanted patients (PTDLs). KSHV, an etiologic agent of Kaposi’s sarcoma (KS), displays primary effusion lymphoma (PEL) and multicentric Castleman disease (MCD). Many therapeutics, such as bortezomib, CHOP cocktail medications, and natural compounds (e.g., quercetin or curcumin), are administrated to patients affected by γ-herpesvirus infections. These drugs induce apoptosis and autophagy, inhibiting the proliferative and cell cycle progression in these malignancies. In the last decade, many studies conducted by scientists and clinicians have indicated that nanotechnology and nanomedicine could improve the outcome of several treatments in γ-herpesvirus-associated diseases. Some drugs are entrapped in nanoparticles (NPs) expressed on the surface area of polyethylene glycol (PEG). These NPs move to specific tissues and exert their properties, releasing therapeutics in the cell target. To treat EBV- and KSHV-associated diseases, many studies have been performed in vivo and in vitro using virus-like particles (VPLs) engineered to maximize antigen and epitope presentations during immune response. NPs are designed to improve therapeutic delivery, avoiding dissolving the drugs in toxic solvents. They reduce the dose-limiting toxicity and reach specific tissue areas. Several attempts are ongoing to synthesize and produce EBV vaccines using nanosystems.

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

Simple Summary

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

Abstract

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

The Emerging Role of Liquid Biopsy in Gastric Cancer

(1) Background: Liquid biopsy (LB) is a novel diagnostic method with the potential of revolutionizing the prevention, diagnosis, and treatment of several solid tumors. The present paper aims to summarize the current knowledge and explore future possibilities of LB in the management of metastatic gastric cancer. (2) Methods: This narrative review examined the most recent literature on the use of LB-based techniques in metastatic gastric cancer and the current LB-related clinical trial landscape. (3) Results: In gastric cancer, the detection of circulating cancer cells (CTCs) has been recognized to have a prognostic role in all the disease stages. In the setting of localized disease, cell-free DNA (cfDNA) and circulating tumor DNA (ctDNA) qualitative and quantitative detection have the potential to inform on the risk of cancer recurrence and metastatic dissemination. In addition, gastric cancer-released exosomes may play an essential part in metastasis formation. In the metastatic setting, the levels of cfDNA show a positive correlation with tumor burden. There is evidence that circulating tumor microemboli (CTM) in the blood of metastatic patients is an independent prognostic factor for shorter overall survival. Gastric cancer-derived exosomal microRNAs or clonal mutations and copy number variations detectable in ctDNA may contribute resistance to chemotherapy or targeted therapies, respectively. There is conflicting and limited data on CTC-based PD-L1 verification and cfDNA-based Epstein-Barr virus detection to predict or monitor immunotherapy responses. (4) Conclusions: Although preliminary studies analyzing LBs in patients with advanced gastric cancer appear promising, more research is required to obtain better insights into the molecular mechanisms underlying resistance to systemic therapies. Moreover, validation and standardization of LB methods are crucial before introducing them in clinical practice. The feasibility of repeatable, minimally invasive sampling opens up the possibility of selecting or dynamically changing therapies based on prognostic risk or predictive biomarkers, such as resistance markers. Research is warranted to exploit a possible transforming area of cancer care.

Metabolic Control by DNA Tumor Virus-Encoded Proteins

Viruses co-opt a multitude of host cell metabolic processes in order to meet the energy and substrate requirements for successful viral replication. However, due to their limited coding capacity, viruses must enact most, if not all, of these metabolic changes by influencing the function of available host cell regulatory proteins. Typically, certain viral proteins, some of which can function as viral oncoproteins, interact with these cellular regulatory proteins directly in order to effect changes in downstream metabolic pathways. This review highlights recent research into how four different DNA tumor viruses, namely human adenovirus, human papillomavirus, Epstein-Barr virus and Kaposi's associated-sarcoma herpesvirus, can influence host cell metabolism through their interactions with either MYC, p53 or the pRb/E2F complex. Interestingly, some of these host cell regulators can be activated or inhibited by the same virus, depending on which viral oncoprotein is interacting with the regulatory protein. This review highlights how MYC, p53 and pRb/E2F regulate host cell metabolism, followed by an outline of how each of these DNA tumor viruses control their activities. Understanding how DNA tumor viruses regulate metabolism through viral oncoproteins could assist in the discovery or repurposing of metabolic inhibitors for antiviral therapy or treatment of virus-dependent cancers.