• Cancer metastasis
• Oncoviruses
• Signal transduction pathways
• Viral infection

• Humans
• Neoplasms/virology
• Neoplasms/pathology
• Neoplasm Metastasis
• Animals
• Oncogenic Viruses/pathogenicity

• Humans
• Virus Latency/genetics
• Herpesvirus 4, Human/genetics
• Virus Activation/genetics
• Lysine/genetics
• Lymphoid Enhancer-Binding Factor 1/genetics
• Epstein-Barr Virus Infections/genetics
• Protein Isoforms/genetics
• RNA, Small Interfering/genetics
• Histone Deacetylases/genetics
• Gene Expression Regulation, Viral

• P01 AI127335 NIAID NIH HHS
• P20 GM134974 NIGMS NIH HHS
• R01 DE025565 NIDCR NIH HHS
• National Institute of Dental and Craniofacial Research
• National Institute of General Medical Sciences
• Feist-Weiller Cancer Center
• LSU Center for Emerging Viral Threts

• CHIKV-nsP2
• Chikungunya virus
• Wnt/β-catenin signaling pathway
• iCRT14
• β-catenin

• Humans
• beta Catenin/metabolism
• Chikungunya Fever/metabolism
• Chikungunya Fever/virology
• Chikungunya virus/physiology
• Virus Replication
• Wnt Signaling Pathway

• BT/PR20554/Med/29/1107/2016 Department of Biotechnology, Ministry of Science and Technology, India (DBT)
• Council of Scientific and Industrial Research, India (CSIR)
• Indian Council of Medical Research (ICMR)
• BT/NBM0101/02/2018 DBT | Biotechnology Industry Research Assistance Council (BIRAC)

• UL8
• Wnt signaling
• human cytomegalovirus
• viral reactivation

• Humans
• Antigens, CD34/metabolism
• beta Catenin/chemistry
• beta Catenin/metabolism
• Cytomegalovirus/genetics
• Cytomegalovirus/physiology
• Dishevelled Proteins/chemistry
• Dishevelled Proteins/metabolism
• Hematopoietic Stem Cells/metabolism
• Hematopoietic Stem Cells/virology
• PDZ Domains
• Viral Proteins/chemistry
• Viral Proteins/metabolism
• Virus Activation
• Virus Latency/genetics

• P01 AI127335 NIAID NIH HHS
• R37 AI021640 NIAID NIH HHS
• HHS | NIH | National Institute of Allergy and Infectious Diseases (NIAID)

• RNA-Seq
• flounder (Paralichthys olivaceus)
• lymphocystis disease virus
• lymphocystis formation
• molecular mechanism
• transcriptome

• Animals
• Flounder/genetics
• Hedgehog Proteins
• Reproducibility of Results
• DNA Virus Infections/genetics
• DNA Virus Infections/veterinary
• DNA Virus Infections/metabolism
• Gene Expression Profiling
• Iridoviridae/physiology

• National Natural Science Foundation of China

• Humans
• Retroviridae
• Neoplasms/pathology
• Carcinogenesis
• Cell Transformation, Neoplastic
• Oncogenes

• protein vaccines
• herpes virus
• viral infection
• infection

• Mice
• Animals
• Herpesvirus 4, Human
• Epstein-Barr Virus Infections/prevention & control
• CD8-Positive T-Lymphocytes
• Epitopes, T-Lymphocyte
• Lymph Nodes
• Vaccines, Subunit

• EBNA1
• EBV
• EBVaGC
• LMP2A
• NRF1

• Humans
• Epstein-Barr Virus Infections/complications
• Epstein-Barr Virus Infections/genetics
• Herpesvirus 4, Human/genetics
• Stomach Neoplasms
• Nuclear Respiratory Factor 1/metabolism
• NF-kappa B/metabolism
• Viral Matrix Proteins/genetics
• Viral Matrix Proteins/metabolism

• ZR2020MC020 Natural Science Foundation of Shandong Province
• ZR2020MH302 Natural Science Foundation of Shandong Province

• Autophagy
• EBV
• Lytic
• Therapy
• Tumorigenesis

Bovine viral diarrhea virus 1 (BVDV-1) of the pestivirus genus is an economically crippling virus in the cattle industry; this positive RNA virus causes mucosal disease resulting in reproductive losses and other disease syndromes. The pathogenesis mechanism of the disease caused by BVDV infection is not well understood; for a better understanding of in vivo host BVDV-1 interactions, we conducted a transcriptomic study of infected cells at different times post-infection.

We compared the permissiveness and cellular response of a BVDV-1 cytopathogenic strain on Madin-Darby Bovine Kidney cells (MDBK) and bovine lung primary cells, a model closer to in vivo infection. Then a RNAseq analysis was realized on the infected bovine lung primary cells, at 10 hpi and 30 hpi (hours post-infection), to identify transcriptomic signatures.

RNAseq analysis on BVDV-1 infected bovine primary cells showed 2,759 and 5,376 differentially expressed genes at respectively 10 hpi and 30 hpi with an absolute Fold Change  ≥ 2. Among the different pathways deregulated, data analysis revealed a deregulation of Wnt signaling pathway, a conserved process that play a critical role in embryogenesis, cellular proliferation, and differentiation as well as in viral responses against viruses such as Influenza or Hepatitis C. We demonstrated here that the deregulation of the Wnt/βcatenin signaling pathway plays a role in viral replication of BVDV cp strain. Interestingly, we showed that the inhibition of this Wnt pathway using two inhibitors, FZM1 and iCRT14, induced a delay in onset of the establishment of a cytopathic effect of primary cells.

Thereby, this study highlighted a role of the Wnt signaling pathway in the BVDV-1 viral replication in bovine cells, suggesting an interesting option to explore as a new therapeutic target.

Epstein–Barr virus (EBV) is the first discovered human tumor virus, which contributes to the oncogenesis of many human cancers. The ubiquitin–proteasome system is a key player during EBV-mediated oncogenesis and has been developed as a crucial therapeutic target for treatment. In this review, we briefly describe how EBV antigens can modulate the ubiquitin–proteasome system for targeted protein degradation and how they are regulated in the EBV life cycle to mediate oncogenesis. Additionally, the developed proteasome inhibitors are discussed for the treatment of EBV-associated cancers.

Deregulation of the ubiquitin–proteasome system (UPS) plays a critical role in the development of numerous human cancers. Epstein–Barr virus (EBV), the first known human tumor virus, has evolved distinct molecular mechanisms to manipulate the ubiquitin–proteasome system, facilitate its successful infection, and drive opportunistic cancers. The interactions of EBV antigens with the ubiquitin–proteasome system can lead to oncogenesis through the targeting of cellular factors involved in proliferation. Recent studies highlight the central role of the ubiquitin–proteasome system in EBV infection. This review will summarize the versatile strategies in EBV-mediated oncogenesis that contribute to the development of specific therapeutic approaches to treat EBV-associated malignancies.

• EBV
• oncogenesis
• ubiquitin–proteasome system

Increasing evidence suggests that microorganisms might represent at least highly interesting cofactors in colorectal cancer (CRC) oncogenesis and progression. Still, associated mechanisms, specifically in colonocytes and their microenvironmental interactions, are still poorly understood. Although, currently, at least seven viruses are being recognized as human carcinogens, only three of these – Epstein–Barr virus (EBV), human papillomavirus (HPV) and John Cunningham virus (JCV) – have been described, with varying levels of evidence, in CRC. In addition, cytomegalovirus (CMV) has been associated with CRC in some publications, albeit not being a fully acknowledged oncovirus. Moreover, recent microbiome studies set increasing grounds for new hypotheses on bacteriophages as interesting additional modulators in CRC carcinogenesis and progression. The present Review summarizes how particular groups of viruses, including bacteriophages, affect cells and the cellular and microbial microenvironment, thereby putatively contributing to foster CRC. This could be achieved, for example, by promoting several processes – such as DNA damage, chromosomal instability, or molecular aspects of cell proliferation, CRC progression and metastasis – not necessarily by direct infection of epithelial cells only, but also by interaction with the microenvironment of infected cells. In this context, there are striking common features of EBV, CMV, HPV and JCV that are able to promote oncogenesis, in terms of establishing latent infections and affecting p53‐/pRb‐driven, epithelial–mesenchymal transition (EMT)‐/EGFR‐associated and especially Wnt/β‐catenin‐driven pathways. We speculate that, at least in part, such viral impacts on particular pathways might be reflected in lasting (e.g. mutational or further genomic) fingerprints of viruses in cells. Also, the complex interplay between several species within the intestinal microbiome, involving a direct or indirect impact on colorectal and microenvironmental cells but also between, for example, phages and bacterial and viral pathogens, and further novel species certainly might, in part, explain ongoing difficulties to establish unequivocal monocausal links between specific viral infections and CRC.

• colorectal cancer
• metastasis
• phages
• viruses

• HBV
• HCV
• HIV
• cancer epidemic
• epidemiology
• histopathology
• molecular biomarkers
• public health
• sub-Saharan Africa
• treatment
• viral oncology

Epstein-Barr virus (EBV) is closely associated with multiple human cancers. EBV-associated cancers are mainly lymphomas derived from B cells and T cells (Hodgkin lymphoma, Burkitt lymphoma, NK/T-cell lymphoma, and posttransplant lymphoproliferative disorder (PTLD)) and carcinomas derived from epithelial cells (nasopharyngeal carcinoma and gastric carcinoma). EBV can induce oncogenesis in its host cell by activating various signaling pathways, such as nuclear factor-κB (NF-κB), phosphoinositide-3-kinase/protein kinase B (PI3K/AKT), Janus kinase/signal transducer and transcription activator (JAK/STAT), mitogen-activated protein kinase (MAPK), transforming growth factor-β (TGF-β), and Wnt/β-catenin, which are regulated by EBV-encoded proteins and noncoding RNA. In this review, we focus on the oncogenic roles of EBV that are mediated through the aforementioned signaling pathways.

• Cancer
• Epstein‐barr virus (EBV)
• Signaling pathway

Epstein–Barr-virus-associated Gastric Cancer (EBVaGC) comprises approximately 10% of global gastric cancers and is known to be the most hypermethylated of all tumor types. EBV infection has been shown to directly induce the hypermethylation of both the host and viral genome following initial infection of gastric epithelial cells. Many studies have been completed in an attempt to identify genes that frequently become hypermethylated and therefore significant pathways that become silenced to promote tumorigenesis. It is clear that EBV-induced hypermethylation silences key tumor suppressor genes, cell cycle genes and cellular differentiation factors to promote a highly proliferative and poorly differentiated cell population. EBV infection has been shown to induce methylation in additional malignancies including Nasopharyngeal Carcinoma and Burkitt’s Lymphoma though not to the same level as in EBVaGC. Lastly, some genes silenced in EBVaGC are common to other heavily methylated tumors such as colorectal and breast tumors; however, some genes are unique to EBVaGC and can provide insights into the major pathways involved in tumorigenesis.

• CpG island
• EBV
• Epstein–Barr virus
• differentiation
• gastric cancer
• hypermethylation
• tumor suppressor gene

• Carcinogenesis/genetics
• CpG Islands
• DNA Methylation/genetics
• Epstein-Barr Virus Infections/complications
• Gene Expression Regulation, Neoplastic
• Genome
• Herpesvirus 4, Human/pathogenicity
• Humans
• Stomach Neoplasms/genetics
• Stomach Neoplasms/physiopathology
• Tumor Suppressor Proteins/genetics

• T32 CA009111 NCI NIH HHS

• E2F-Rb-HDAC
• Epstein-Barr virus
• KLF14
• latent infection

Human cytomegalovirus (HCMV) causes significant disease in immunocompromised individuals, including transplant patients. HCMV establishes latency in hematopoietic stem cells in the bone marrow. The mechanisms governing latency and reactivation of viral replication are complex and not fully understood. HCMV-encoded miRNAs are small regulatory RNAs that reduce protein expression. In this study, we found that the HCMV miRNA miR-US5-2 targets the epidermal growth factor receptor (EGFR) adaptor protein GAB1 which directly affects downstream cellular signaling pathways activated by EGF. Consequently, miR-US5-2 blocks the EGF-mediated proliferation of human fibroblasts. Early growth response gene 1 (EGR1) is a transcription factor activated by EGFR signaling that regulates expression of HCMV UL138. We show that miR-US5-2 regulates UL138 expression through GAB1-mediated downregulation of the signaling pathways that lead to EGR1 expression. These data suggest that miR-US5-2, through downregulation of GAB1, could play a critical role during reactivation from latency by reducing proliferation and UL138 expression.

Regulation of epidermal growth factor (EGF) receptor (EGFR) signaling is critical for the replication of human cytomegalovirus (HCMV) as well as latency and reactivation in CD34⁺ hematopoietic progenitor cells. HCMV microRNAs (miRNAs) provide a means to modulate the signaling activated by EGF through targeting components of the EGFR signaling pathways. Here, we demonstrate that HCMV miR-US5-2 directly downregulates the critical EGFR adaptor protein GAB1 that mediates activation and sustained signaling through the phosphatidylinositol 3-kinase (PI3K) and MEK/extracellular signal-regulated kinase (ERK) pathways and cellular proliferation in response to EGF. Expression of HCMV UL138 is regulated by the transcription factor early growth response gene 1 (EGR1) downstream of EGFR-induced MEK/ERK signaling. We show that by targeting GAB1 and attenuating MEK/ERK signaling, miR-US5-2 indirectly regulates EGR1 and UL138 expression, which implicates the miRNA in critical regulation of HCMV latency.

IMPORTANCE Human cytomegalovirus (HCMV) causes significant disease in immunocompromised individuals, including transplant patients. HCMV establishes latency in hematopoietic stem cells in the bone marrow. The mechanisms governing latency and reactivation of viral replication are complex and not fully understood. HCMV-encoded miRNAs are small regulatory RNAs that reduce protein expression. In this study, we found that the HCMV miRNA miR-US5-2 targets the epidermal growth factor receptor (EGFR) adaptor protein GAB1 which directly affects downstream cellular signaling pathways activated by EGF. Consequently, miR-US5-2 blocks the EGF-mediated proliferation of human fibroblasts. Early growth response gene 1 (EGR1) is a transcription factor activated by EGFR signaling that regulates expression of HCMV UL138. We show that miR-US5-2 regulates UL138 expression through GAB1-mediated downregulation of the signaling pathways that lead to EGR1 expression. These data suggest that miR-US5-2, through downregulation of GAB1, could play a critical role during reactivation from latency by reducing proliferation and UL138 expression.

• GAB1
• UL138
• cytomegalovirus
• miRNA

• DNA virus
• Human cytomegalovirus
• UL135
• UL136
• UL138
• herpesvirus
• latency
• reactivation

• Animals
• Cytomegalovirus/genetics
• Cytomegalovirus/physiology
• Cytomegalovirus Infections/virology
• Humans
• Viral Proteins/genetics
• Viral Proteins/metabolism
• Virus Activation
• Virus Latency

• R37 AI079059 NIAID NIH HHS
• R01 AI079059 NIAID NIH HHS
• R01 AI131598 NIAID NIH HHS
• AI079059 National Institute of Allergy and Infectious Diseases
• AI127335 National Institute of Allergy and Infectious Diseases

• EBV-associated gastric carcinoma
• Metastasis
• Wnt signaling pathway
• ebv-miR-BART10-3p
• ebv-miR-BART22
• microRNAs

The rapid activation of the type I interferon (IFN) antiviral innate immune response relies on ubiquitously expressed RNA and DNA sensors. Once engaged, these nucleotide-sensing receptors use distinct signaling modules for the rapid and robust activation of mitogen-activated protein kinases (MAPKs), the IκB kinase (IKK) complex, and the IKK-related kinases IKKε and TANK-binding kinase 1 (TBK1), leading to the subsequent activation of the activator protein 1 (AP1), nuclear factor-kappa B (NF-κB), and IFN regulatory factor 3 (IRF3) transcription factors, respectively. They, in turn, induce immunomodulatory genes, allowing for a rapid antiviral cellular response. Unlike the MAPKs, the IKK complex and the IKK-related kinases, ubiquitously expressed glycogen synthase kinase 3 (GSK-3) α and β isoforms are active in unstimulated resting cells and are involved in the constitutive turnover of β-catenin, a transcriptional coactivator involved in cell proliferation, differentiation, and lineage commitment. Interestingly, studies have demonstrated the regulatory roles of both GSK-3 and β-catenin in type I IFN antiviral innate immune response, particularly affecting the activation of IRF3. In this review, we summarize current knowledge on the mechanisms by which GSK-3 and β-catenin control the antiviral innate immune response to RNA and DNA virus infections.

• GSK-3
• RIG-like receptors (RLR)
• TBK1
• cGAS
• innate antiviral immunity
• toll-like receptors (TLR)
• type I IFN response
• β-catenin

• Animals
• Glycogen Synthase Kinase 3/metabolism
• Humans
• Immunity, Innate/genetics
• Nucleic Acids/metabolism
• Signal Transduction
• beta Catenin/metabolism

• MOP-142232 CIHR

• tumour virus infections
• diagnostic markers

• Animals
• Cell Proliferation
• Epstein-Barr Virus Infections/genetics
• Humans
• Mice
• Mice, Nude
• Nasopharyngeal Carcinoma/genetics
• Nasopharyngeal Carcinoma/metabolism
• Viral Matrix Proteins/metabolism

• National Natural Science Foundation of China (National Science Foundation of China)
• Zhejiang Province Public Welfare Technology Application Research Project (Public Welfare Technology Application Research Project of Zhejiang Province)
• Natural Science Foundation of Ningbo (Ningbo Natural Science Foundation)

Sustained phosphotinositide3-kinase (PI3K) signaling is critical to the maintenance of alpha and beta herpesvirus latency. We have previously shown that the beta-herpesvirus, human cytomegalovirus (CMV), regulates epidermal growth factor receptor (EGFR), upstream of PI3K, to control states of latency and reactivation. How signaling downstream of EGFR is regulated and how this impacts CMV infection and latency is not fully understood. We demonstrate that CMV downregulates EGFR early in the productive infection, which blunts the activation of EGFR and its downstream pathways in response to stimuli. However, CMV infection sustains basal levels of EGFR and downstream pathway activity in the context of latency in CD34+ hematopoietic progenitor cells (HPCs). Inhibition of MEK/ERK, STAT or PI3K/AKT pathways downstream of EGFR increases viral reactivation from latently infected CD34⁺ HPCs, defining a role for these pathways in latency. We hypothesized that CMV modulation of EGFR signaling might impact viral transcription important to latency. Indeed, EGF-stimulation increased expression of the UL138 latency gene, but not immediate early or early viral genes, suggesting that EGFR signaling promotes latent gene expression. The early growth response-1 (EGR1) transcription factor is induced downstream of EGFR signaling through the MEK/ERK pathway and is important for the maintenance of hematopoietic stemness. We demonstrate that EGR1 binds the viral genome upstream of UL138 and is sufficient to promote UL138 expression. Further, disruption of EGR1 binding upstream of UL138 prevents the establishment of latency in CD34⁺ HPCs. Our results indicate a model whereby UL138 modulation of EGFR signaling feeds back to promote UL138 gene expression and suppression of replication for latency. By this mechanism, the virus has hardwired itself into host cell biology to sense and respond to changes in homeostatic host cell signaling.

Host signaling is important for regulating states of cytomegalovirus (CMV) replication and latency. We have shown that human cytomegalovirus regulates EGFR levels and trafficking and that sustained EGFR or downstream PI3K signaling is a requirement for viral latency. Changes in host signaling have the ability to alter viral and host gene expression to impact the outcome of infection. Here we show that EGFR signaling through MEK/ERK pathway induces the host EGR1 transcription factor that is highly expressed in hematopoietic stem cells and necessary for the maintenance of hematopoietic stemness. Downregulation of EGR1 promotes stem cell mobilization and differentiation, known stimuli for CMV reactivation. We identified functional EGR1 binding sites upstream of the UL138 CMV latency gene and EGR1 stimulated UL138 expression to reinforce the latent infection. Mutant viruses where the regulation of UL138 by EGR1 is disrupted are unable to establish latency in CD34⁺ HPCs. This study advances our understanding of how host signaling impacts decisions to enter into or exit from latency. The regulation of viral gene expression by host signaling allows the virus to sense and respond to changes in host stress or differentiation.

• Cytomegalovirus/physiology
• Cytomegalovirus Infections/genetics
• Cytomegalovirus Infections/metabolism
• Cytomegalovirus Infections/virology
• Early Growth Response Protein 1/genetics
• Early Growth Response Protein 1/metabolism
• Gene Expression Regulation, Viral
• Genome, Viral
• Hematopoietic Stem Cells/metabolism
• Hematopoietic Stem Cells/pathology
• Hematopoietic Stem Cells/virology
• Host-Pathogen Interactions
• Humans
• Viral Proteins/genetics
• Viral Proteins/metabolism
• Virus Latency
• Virus Replication

• R01 AI079059 NIAID NIH HHS
• T32 CA009213 NCI NIH HHS
• T32 AI007472 NIAID NIH HHS
• R37 AI021640 NIAID NIH HHS
• R01 AI021640 NIAID NIH HHS
• P01 AI127335 NIAID NIH HHS
• R37 AI079059 NIAID NIH HHS

Association of Epstein-Barr virus (EBV) encoded latent gene products with host ribosomal proteins (RPs) has not been fully explored, despite their involvement in the aetiology of several human cancers. To gain an insight into their plausible interactions, we employed a computational approach that encompasses structural alignment, gene ontology analysis, pathway analysis, and molecular docking.

In this study, the alignment analysis based on structural similarity allows the prediction of 48 potential interactions between 27 human RPs and the EBV proteins EBNA1, LMP1, LMP2A, and LMP2B. Gene ontology analysis of the putative protein-protein interactions (PPIs) reveals their probable involvement in RNA binding, ribosome biogenesis, metabolic and biosynthetic processes, and gene regulation. Pathway analysis shows their possible participation in viral infection strategies (viral translation), as well as oncogenesis (Wnt and EGFR signalling pathways). Finally, our molecular docking assay predicts the functional interactions of EBNA1 with four RPs individually: EBNA1-eS10, EBNA1-eS25, EBNA1-uL10 and EBNA1-uL11.

These interactions have never been revealed previously via either experimental or in silico approach. We envisage that the calculated interactions between the ribosomal and EBV proteins herein would provide a hypothetical model for future experimental studies on the functional relationship between ribosomal proteins and EBV infection.

The online version of this article (10.1186/s12860-019-0219-y) contains supplementary material, which is available to authorized users.

• Computational prediction
• EBNA1
• Epstein-Barr virus
• Protein-protein interactions
• Ribosomal proteins

Angiogenesis is the biological process by which new blood vessels are formed from pre-existing vessels. It is considered one of the classic hallmarks of cancer, as pathological angiogenesis provides oxygen and essential nutrients to growing tumors. Two of the seven known human oncoviruses, Epstein–Barr virus (EBV) and Kaposi’s sarcoma-associated herpesvirus (KSHV), belong to the Gammaherpesvirinae subfamily. Both viruses are associated with several malignancies including lymphomas, nasopharyngeal carcinomas, and Kaposi’s sarcoma. The viral genomes code for a plethora of viral factors, including proteins and non-coding RNAs, some of which have been shown to deregulate angiogenic pathways and promote tumor growth. In this review, we discuss the ability of both viruses to modulate the pro-angiogenic process.

• Epstein–Barr virus
• Kaposi’s sarcoma-associated herpesvirus
• angiogenesis
• gammaherpesviruses
• oncoviruses
• vascular endothelial growth factor

• EBV
• Epstein-Barr virus
• PI3K
• gastric cancer
• immunotherapy
• methylation

• P30 CA014236 NCI NIH HHS

• EBV
• Nasopharyngeal carcinoma
• lncRNA
• metastasis
• miRNA
• regulation

• epigenetic regulation
• human cytomegalovirus
• latency
• reactivation
• signaling
• transcription factors

• Bone Marrow Cells/virology
• Cytomegalovirus/genetics
• Cytomegalovirus/pathogenicity
• Cytomegalovirus Infections/virology
• Epithelial Cells/virology
• Gene Expression Regulation, Viral
• Genome, Viral
• Host-Pathogen Interactions
• Humans
• Macrophages/virology
• Signal Transduction
• Virus Activation/genetics
• Virus Latency/genetics
• Virus Replication/genetics

• P01 AI127335 NIAID NIH HHS

The Epstein-Barr virus (EBV) oncoproteins latent membrane protein 1 (LMP1) and LMP2A constitutively activate multiple signaling pathways, and both have been shown to interact with cellular ubiquitin ligases and affect cellular ubiquitination. To detect the LMP1- and LMP2A-mediated effects on the global cellular proteome, epithelial cell lines expressing LMP1 or LMP2A were analyzed using label-free quantitative proteomics. To identify proteins whose ubiquitination is affected by the viral proteins, the cells were cultured in the presence and absence of deubiquitinase (DUB) and proteasome inhibitors. More than 7,700 proteins were identified with high confidence and considerably more proteins showed significant differences in expression in the presence of inhibitors. Few of the differentially expressed proteins with or without inhibitors were common between LMP1 and LMP2A, confirming that the viral proteins induce unique changes in cell expression and function. However, ingenuity pathway analysis (IPA) of the data indicated that LMP1 and LMP2A modulate many of the same cellular regulatory pathways, including cell death and survival, cell movement, and actin filament dynamics. In addition, various proteasome subunits, ubiquitin-specific peptidases and conjugating enzymes, vesicle trafficking proteins, and NF-κB and mitogen-activated protein kinase signaling proteins were affected by LMP1 or LMP2A. These findings suggest that LMP1 and LMP2A may commonly target critical cell pathways through effects on distinct genes, with many cellular proteins modified by ubiquitination and/or degradation.

The Epstein-Barr virus proteins latent membrane protein 1 and 2 have potent effects on cell growth and signaling. Both proteins bind to specific ubiquitin ligases and likely modulate the cellular proteome through ubiquitin-mediated effects on stability and intracellular location. In this study, a comprehensive proteomic analysis of the effects of LMP1 and LMP2A revealed that both proteins affected proteasome subunits, ubiquitin-specific conjugases and peptidases, and vesical trafficking proteins. The data suggest that the effects of these proteins on the abundance and ubiquitination of cellular proteins are in part responsible for their effects on cell growth regulation.

• EBV
• NPC
• p63
• transactivation
• transcription

Epstein-Barr virus (EBV)-associated carcinomas, such as nasopharyngeal carcinoma (NPC), exhibit an undifferentiated and metastatic phenotype. To determine viral contributions involved in the invasive phenotype of EBV-associated carcinomas, EBV-infected human telomerase-immortalized normal oral keratinocytes (NOK) were investigated. EBV-infected NOK were previously shown to undergo epigenetic reprogramming involving CpG island hypermethylation and delayed responsiveness to differentiation. Here, we show that EBV-infected NOK acquired an invasive phenotype that was epigenetically retained after viral loss. The transcription factor lymphoid enhancer factor 1 (LEF1) and the secreted ligand WNT5A, expressed in NPC, were increased in EBV-infected NOK with sustained expression for more than 20 passages after viral loss. Increased LEF1 levels involved four LEF1 variants, and EBV-infected NOK showed a lack of responsiveness to β-catenin activation. Although forced expression of WNT5A and LEF1 enhanced the invasiveness of parental NOK, LEF1 knockdown reversed the invasive phenotype of EBV-infected NOK in the presence of WNT5A. Viral reprogramming of LEF1 and WNT5A was observed several passages after EBV infection, suggesting that LEF1 and WNT5A may provide a selective advantage to virally-infected cells. Our findings suggest that EBV epigenetically reprogrammed epithelial cells with features of basal, wound healing keratinocytes, with LEF1 contributing to the metastatic phenotype of EBV-associated carcinomas.

• Epstein-Barr virus
• LEF1
• WNT
• epigenetics
• invasion

• Litopenaeus vannamei
• Ubiquitination
• WSSV
• Wnt/β-catenin pathway
• β-catenin

• Animals
• Arthropod Proteins/genetics
• Arthropod Proteins/metabolism
• Cell Nucleus/metabolism
• Cells, Cultured
• Cloning, Molecular
• Gene Expression Regulation
• Gene Expression Regulation, Viral
• Glycogen Synthase Kinase 3/metabolism
• Immunomodulation
• Penaeidae/immunology
• Penaeidae/virology
• Protein Transport
• Virus Diseases/immunology
• Virus Diseases/metabolism
• White spot syndrome virus 1/immunology
• Wnt Signaling Pathway
• beta Catenin/genetics
• beta Catenin/metabolism

• Apoptosis
• Cisplatin
• Epithelial–mesenchymal transition
• Nasopharyngeal carcinoma
• TIMELESS
• Wnt/β-catenin pathway

• Adult
• Animals
• Antineoplastic Agents/pharmacology
• Apoptosis/drug effects
• Biomarkers, Tumor/genetics
• Biomarkers, Tumor/metabolism
• Carcinoma/drug therapy
• Carcinoma/genetics
• Carcinoma/metabolism
• Carcinoma/pathology
• Cell Cycle Proteins/genetics
• Cell Cycle Proteins/metabolism
• Cell Line, Tumor
• Cisplatin/pharmacology
• Disease-Free Survival
• Dose-Response Relationship, Drug
• Drug Resistance, Neoplasm
• Epithelial-Mesenchymal Transition/drug effects
• Female
• Gene Expression Regulation, Neoplastic
• Humans
• Intracellular Signaling Peptides and Proteins/genetics
• Intracellular Signaling Peptides and Proteins/metabolism
• Kaplan-Meier Estimate
• Male
• Mice, Inbred BALB C
• Mice, Nude
• Middle Aged
• Nasopharyngeal Carcinoma
• Nasopharyngeal Neoplasms/drug therapy
• Nasopharyngeal Neoplasms/genetics
• Nasopharyngeal Neoplasms/metabolism
• Nasopharyngeal Neoplasms/pathology
• Neoplasm Grading
• Neoplasm Staging
• Phenotype
• Proportional Hazards Models
• RNA Interference
• Time Factors
• Transcription, Genetic
• Transfection
• Wnt Signaling Pathway/drug effects
• Xenograft Model Antitumor Assays

• Mycobacterium tuberculosis
• Wnt proteins
• beta catenin
• granuloma
• inflammation
• macrophages
• toll-like receptors

• Axin
• Cytomegalovirus
• Epstein-Barr virus
• Glycogen synthase kinase-3
• Herpes simplex virus-1
• Herpesvirus
• Kaposi’s sarcoma-associated herpesvirus
• Varicella zoster virus
• Wnt/β-catenin

• expression quantitative trait locus
• genome-wide association study
• single nucleotide variant
• telomerase
• wnt signaling pathway

• DNA, Neoplasm
• Gene Expression Regulation, Neoplastic
• Genetic Predisposition to Disease
• Genome-Wide Association Study
• Humans
• Neoplasms/genetics
• Neoplasms/metabolism
• Polymorphism, Single Nucleotide
• Quantitative Trait Loci
• RNA/genetics
• Telomerase/biosynthesis
• Telomerase/genetics
• Telomerase/metabolism

• Heat shock protein 60 (HSP60)
• c-Myc
• p110α
• transformation

Herpesviruses persist indefinitely in their host through complex and poorly defined interactions that mediate latent, chronic or productive states of infection. Human cytomegalovirus (CMV or HCMV), a ubiquitous β-herpesvirus, coordinates the expression of two viral genes, UL135 and UL138, which have opposing roles in regulating viral replication. UL135 promotes reactivation from latency and virus replication, in part, by overcoming replication-suppressive effects of UL138. The mechanism by which UL135 and UL138 oppose one another is not known. We identified viral and host proteins interacting with UL138 protein (pUL138) to begin to define the mechanisms by which pUL135 and pUL138 function. We show that pUL135 and pUL138 regulate the viral cycle by targeting that same receptor tyrosine kinase (RTK) epidermal growth factor receptor (EGFR). EGFR is a major homeostatic regulator involved in cellular proliferation, differentiation, and survival, making it an ideal target for viral manipulation during infection. pUL135 promotes internalization and turnover of EGFR from the cell surface, whereas pUL138 preserves surface expression and activation of EGFR. We show that activated EGFR is sequestered within the infection-induced, juxtanuclear viral assembly compartment and is unresponsive to stress. Intriguingly, these findings suggest that CMV insulates active EGFR in the cell and that pUL135 and pUL138 function to fine-tune EGFR levels at the cell surface to allow the infected cell to respond to extracellular cues. Consistent with the role of pUL135 in promoting replication, inhibition of EGFR or the downstream phosphoinositide 3-kinase (PI3K) favors reactivation from latency and replication. We propose a model whereby pUL135 and pUL138 together with EGFR comprise a molecular switch that regulates states of latency and replication in HCMV infection by regulating EGFR trafficking to fine tune EGFR signaling.

Cytomegalovirus, a herpesvirus, persists in its host through complex interactions that mediate latent, chronic or productive states of infection. Defining the mechanistic basis viral persistence is important for defining the costs and possible benefits of viral persistence and to mitigate pathologies associated with reactivation. We have identified two genes, UL135 and UL138, with opposing roles in regulating states of latency and replication. UL135 promotes replication and reactivation from latency, in part, by overcoming suppressive effects of UL138. Intriguingly, pUL135 and pUL138 regulate the viral cycle by targeting the same receptor tyrosine kinase, epidermal growth factor receptor (EGFR). EGFR is a major homeostatic regulator controlling cellular proliferation, differentiation, and survival, making it an ideal target for viruses to manipulate during infection. We show that CMV insulates and regulates EGFR levels and activity by modulating its trafficking. This work defines a molecular switch that regulates latent and replicative states of infection through the modulation of host trafficking and signaling pathways. The regulation of EGFR at the cell surface provides a novel means by which the virus may sense and respond to changes in the host environment to enter into or exit the latent state.

• Cell Line
• Cytomegalovirus
• Cytomegalovirus Infections/metabolism
• ErbB Receptors/metabolism
• Flow Cytometry
• Fluorescent Antibody Technique
• Humans
• Immunoblotting
• Immunoprecipitation
• Mass Spectrometry
• Protein Transport
• Virus Latency/physiology
• Virus Replication/physiology

• R37 AI079059 NIAID NIH HHS
• P30 CA023074 NCI NIH HHS
• R01 AI079059 NIAID NIH HHS
• T32 CA009213 NCI NIH HHS
• R56 AI105062 NIAID NIH HHS
• R01 AI083281 NIAID NIH HHS
• National Institute of Allergy and Infectious Diseases
• National Cancer Institute
• Pew Charitable Trusts

The interplay between host cell genetics and Epstein-Barr virus (EBV) infection contributes to the development of nasopharyngeal carcinoma (NPC). Understanding the host genetic and epigenetic alterations and the influence of EBV on cell signaling and host gene regulation will aid in understanding the molecular pathogenesis of NPC and provide useful biomarkers and targets for diagnosis and therapy. In this review, we provide an update of the oncogenes and tumor suppressor genes associated with NPC, as well as genes associated with NPC risk including those involved in carcinogen detoxification and DNA repair. We also describe the importance of host genetics that govern the human leukocyte antigen (HLA) complex and immune responses, and we describe the impact of EBV infection on host cell signaling changes and epigenetic regulation of gene expression. High-power genomic sequencing approaches are needed to elucidate the genetic basis for inherited susceptibility to NPC and to identify the genes and pathways driving its molecular pathogenesis.

• Wnt pathway
• Wnt-C59
• cancer stem cells
• nasopharyngeal carcinoma
• tumor suppression

• Animals
• Carcinoma
• Cell Line, Tumor
• Cell Proliferation
• Genes, Tumor Suppressor/drug effects
• Humans
• Immunohistochemistry
• Mice
• Nasopharyngeal Carcinoma
• Nasopharyngeal Neoplasms/genetics
• Neoplastic Stem Cells/metabolism
• Neoplastic Stem Cells/pathology
• Tumor Microenvironment
• Wnt Signaling Pathway/genetics

• Akt
• Cytomegalovirus
• Epstein-Barr virus
• Herpes simplex
• Herpesvirus
• Kaposi׳s sarcoma associated herpesvirus
• PI3K
• Varicella-zoster

• Antiviral Agents/pharmacology
• Herpesviridae/physiology
• Herpesviridae Infections/drug therapy
• Host-Pathogen Interactions
• Humans
• Oncogene Protein v-akt/antagonists & inhibitors
• Oncogene Protein v-akt/metabolism
• Phosphatidylinositol 3-Kinase/metabolism
• Phosphoinositide-3 Kinase Inhibitors
• Signal Transduction
• Viral Proteins/metabolism
• Virus Latency
• Virus Replication

• Z01 AI000058-34 Intramural NIH HHS

Latent Epstein–Barr virus (EBV) infection has a substantial role in causing many human disorders. The persistence of these viral genomes in all malignant cells, yet with the expression of limited latent genes, is consistent with the notion that EBV latent genes are important for malignant cell growth. While the EBV-encoded nuclear antigen-1 (EBNA-1) and latent membrane protein-2A (LMP-2A) are critical, the EBNA-leader proteins, EBNA-2, EBNA-3A, EBNA-3C and LMP-1, are individually essential for in vitro transformation of primary B cells to lymphoblastoid cell lines. EBV-encoded RNAs and EBNA-3Bs are dispensable. In this review, the roles of EBV latent genes are summarized.

• BART miRNAs
• Exosomes
• Latent membrane proteins 1 and 2
• Nasopharyngeal carcinoma
• Transformation