STAT3 activation induced by Epstein-Barr virus latent membrane protein1 causes vascular endothelial growth factor expression and cellular invasiveness via JAK3 And ERK signaling

EBV Vaccines in the Prevention and Treatment of Nasopharyngeal Carcinoma

Epstein-Barr virus (EBV), a ubiquitous human herpesvirus, has been robustly linked to the pathogenesis of nasopharyngeal carcinoma (NPC). The mechanism of EBV-induced NPC involves complex interactions between viral proteins and host cell pathways. This review aims to comprehensively outline the mechanism of EBV-induced NPC and the latest advances in targeted EBV vaccines for prophylaxis and treatment. This review explores the intricate molecular mechanisms by which EBV contributes to NPC pathogenesis, highlighting viral latency, genetic and epigenetic alterations, and immune evasion strategies. It emphasizes the pivotal role of key viral proteins, including EBNA1, LMP1, and LMP2A, in carcinogenesis. Subsequently, the discussion shifts towards the development of targeted EBV vaccines, including preventive vaccines aimed at preventing primary EBV infection and therapeutic vaccines aimed at treating diagnosed EBV-related NPC. The review underscores the challenges and future directions in the field, stressing the importance of developing innovative vaccine strategies and combination therapies to improve efficacy. This review synthesizes current insights into the molecular mechanisms of EBV-induced NPC and the development of EBV-targeted vaccines, highlighting the potential use of mRNA vaccines for NPC treatment.

Unveiling immune resistance mechanisms in nasopharyngeal carcinoma and emerging targets for antitumor immune response: tertiary lymphoid structures

Nasopharyngeal carcinoma (NPC) is a prevalent malignancy in China, commonly associated with undifferentiated cell types and Epstein-Barr virus (EBV) infection. The presence of intense lymphocytic infiltration and elevated expression of programmed cell death ligand 1(PD-L1) in NPC highlights its potential for immunotherapy, yet current treatment outcomes remain suboptimal. In this review, we explore the tumor microenvironment of NPC to better understand the mechanisms of resistance to immunotherapy, evaluate current therapeutic strategies, and pinpoint emerging targets, such as tertiary lymphoid structures (TLSs), that could enhance treatment outcomes and prognostic accuracy. TLSs have demonstrated positive prognostic value in NPC, making them a promising target for future therapies. This review summarizes the key characteristics of TLSs and latest research in the context of NPC. We are optimistic that targeting TLSs could improve immunotherapy outcomes for NPC patients, ultimately leading to more effective treatment strategies and better patient survival.

War or peace: Viruses and metastasis

Metastasis, the dissemination of malignant cells from a primary tumor to secondary sites, poses a catastrophic burden to cancer treatment and is the predominant cause of mortality in cancer patients. Metastasis as one of the main aspects of cancer progression could be strongly under the influence of viral infections. In fact, viruses have been central to modern cancer research and are associated with a great number of cancer cases. Viral-encoded elements are involved in modulating essential pathways or specific targets that are implicated in different stages of metastasis. Considering the continuous emergence of new viruses and the establishment of their contribution to cancer progression, the warfare between viruses and cancer appears to be endless. Here we aimed to review the critical mechanism and pathways involved in cancer metastasis and the influence of viral machinery and various routes that viruses adopt to manipulate those pathways for their benefit.

Angiogenesis in nasopharyngeal carcinoma: insights, imaging, and therapeutic strategies

Nasopharyngeal carcinoma (NPC) is a highly prevalent head and neck malignancy in southern China frequently diagnosed at advanced stages owing to subtle early symptoms and associated metastasis. Angiogenesis emerges as a pivotal factor in NPC progression, with numerous angiogenesis-related factors showing aberrant expression and contributing to increased neovascularization within NPC tumors. These abnormal vessels not only nourish tumor growth but also facilitate metastasis, culminating in unfavorable patient outcomes. Multiple studies have demonstrated the applicability of various imaging techniques for assessing angiogenesis in NPC tumors, thus serving as a foundation for personalized treatment strategies and prognostic assessments. Anti-angiogenic therapies have exhibited significant potential for inhibiting NPC angiogenesis and exerting anti-tumor effects. To enhance efficacy, anti-angiogenic drugs are frequently combined with other treatment modalities to synergistically enhance anti-tumor effects while mitigating the side effects associated with single-agent therapies, consequently improving patient prognosis. Identifying the potential mechanisms and key targets underlying NPC angiogenesis and exploring more effective detection and treatment approaches holds promise for shaping the future of NPC diagnosis, treatment, and prognosis, thereby offering new avenues and perspectives for research and clinical practice.

Role of the VEGF in virus-associated cancers

The role of numerous risk factors, including consumption of alcohol, smoking, having diet high in fat and sugar and many other items, on caner progression cannot be denied. Viral diseases are one these factors, and they can initiate some signalling pathways causing cancer. For example, they can be effective on providing oxygen and nutrients by inducing VEGF expression. In this review article, we summarised the mechanisms of angiogenesis and VEGF expression in cancerous tissues which are infected with oncoviruses (Epstein-Barr virus, Human papillomavirus infection, Human T-lymphotropic virus, Kaposi's sarcoma-associated herpesvirus, Hepatitis B and hepatitis C virus).

Mechanism of action and therapeutic targeting of CD30 molecule in lymphomas

At present, the treatment of lymphoma has entered the era of precision medicine, and CD30, as a transmembrane protein, has become an important marker to help the diagnosis and formulation of treatment plans for lymphomas. This protein is widely expressed in various types of lymphomas and can play a role through nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), and other pathways, and ultimately lead to the up-regulation of CD30 expression to give tumor cells a survival advantage. Brentuximab vedotin (BV), as an antibody-drug conjugate (ADC) targeting CD30, is one of the first new drugs to significantly improve survival in patients with CD30+lymphomas. However, the biological function of CD30 has not been fully elucidated. Therefore, this review highlights the CD30-mediated tumor-promoting mechanisms and the molecular factors that regulate CD30 expression. We hope that a better understanding of CD30 biology will provide new insights into clinical treatment and improve the survival and quality of life of lymphoma patients.

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

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

STIM1-regulated exosomal EBV-LMP1 empowers endothelial cells with an aggressive phenotype by activating the Akt/ERK pathway in nasopharyngeal carcinoma

BACKGROUND

Stromal interaction molecule 1 (STIM1)-mediated Ca2+ signaling regulates tumor angiogenesis in nasopharyngeal carcinoma (NPC), an Epstein-Barr virus (EBV)-related human malignancy. However, the mechanism by which STIM1 modulates endothelial functional phenotypes contributing to tumor angiogenesis remains elusive.

METHODS

NPC cell-derived exosomes were isolated via differential centrifugation and observed using transmission electron microscopy. Exosome particle sizes were assessed by nanoparticle tracking analysis (NTA). Uptake of exosomes by recipient ECs was detected by fluorescent labeling of the exosomes with PKH26. Tumor angiogenesis-associated profiles were characterized by determining cell proliferation, migration, tubulogenesis and permeability in human umbilical vein endothelial cells (HUVECs). Activation of the Akt/ERK pathway was assessed by detecting the phosphorylation levels using Western blotting. A chick embryo chorioallantoic membrane (CAM) xenograft model was employed to study tumor-associated neovascularization in vivo.

RESULTS

We found that NPC cell-derived exosomes harboring EBV-encoded latent membrane protein 1 (LMP1) promoted proliferation, migration, tubulogenesis and permeability by activating the Akt/ERK pathway in ECs. STIM1 silencing reduced LMP1 enrichment in NPC cell-derived exosomes, thereby reversing its pro-oncogenic effects in an Akt/ERK pathway-dependent manner. Furthermore, STIM1 knockdown in NPC cells blunted tumor-induced vascular network formation and inhibited intra-tumor neovascularization in the chorioallantoic membrane (CAM) xenograft model.

CONCLUSION

STIM1 regulates tumor angiogenesis by controlling exosomal EBV-LMP1 delivery to ECs in the NPC tumor microenvironment. Blocking exosome-mediated cell-to-cell horizontal transfer of EBV-associated oncogenic signaling molecules may be an effective therapeutic strategy for NPC.

Asiatic Acid Inhibits Nasopharyngeal Carcinoma Cell Viability and Migration via Suppressing STAT3 and Claudin-1

Nasopharyngeal carcinoma (NPC) is a prevalent cancer in Southeast Asia, but effective treatment options remain limited, and chemotherapy has a high resistance rate. Asiatic acid (AA), a triterpenoid found in Centella asiatica, has shown anticancer activity in various cancers. Therefore, this study aims to investigate the anticancer effects and mechanisms of AA in NPC cell lines. The effects of AA on NPC cytotoxicity, apoptosis, and migration were determined in TW-01 and SUNE5-8F NPC cell lines. Western blot analysis was performed to evaluate the protein expression levels affected by AA. The role of AA in proliferation and migration was investigated in STAT3 and claudin-1 knockdown cells. AA inhibited NPC cell viability and migration and induced cell death by increasing cleaved caspase-3 expression. Moreover, AA inhibited STAT3 phosphorylation and reduced claudin-1 expression in NPC cells. Although knockdown of STAT3 or claudin-1 slightly reduced cell viability, it did not enhance the anti-proliferative effect of AA. However, knockdown of STAT3 or claudin-1 increased the anti-migratory effect of AA in NPC cells. These results suggest that AA can be a promising candidate for drug development against NPC.

Adiponectin Suppresses Metastasis of Nasopharyngeal Carcinoma through Blocking the Activation of NF-κB and STAT3 Signaling

Adiponectin is an adipocytokine with anti-inflammatory and anticancer properties. Our previous study has shown that blood adiponectin levels were inversely correlated to the risk of nasopharyngeal carcinoma (NPC), and that adiponectin could directly suppress the proliferation of NPC cells. However, the effect of adiponectin on NPC metastasis remains unknown. Here, we revealed in clinical studies that serum adiponectin level was inversely correlated with tumor stage, recurrence, and metastasis in NPC patients, and that low serum adiponectin level also correlates with poor metastasis-free survival. Coculture with recombinant adiponectin suppressed the migration and invasion of NPC cells as well as epithelial-mesenchymal transition (EMT). In addition, recombinant adiponectin dampened the activation of NF-κB and STAT3 signaling pathways induced by adipocyte-derived proinflammatory factors such as leptin, IL-6, and TNF-α. Pharmacological activation of adiponectin receptor through its specific agonist, AdipoRon, largely stalled the metastasis of NPC cells. Taken together, these findings demonstrated that adiponectin could not only regulate metabolism and inhibit cancer growth, but also suppress the metastasis of NPC. Pharmacological activation of adiponectin receptor may be a promising therapeutic strategy to stall NPC metastasis and extend patients' survival.

Role of STAT3 in the pathogenesis of nasopharyngeal carcinoma and its significance in anticancer therapy

Nasopharyngeal carcinoma (NPC) is a type of head and neck tumor with noticeable regional and ethnic differences. It is associated with Epstein-Barr virus infection and has a tendency for local and distant metastasis. NPC is also highly sensitive to radiotherapy and chemotherapy. Over 70% of patients present with locoregionally advanced disease, and distant metastasis is the primary reason for treatment failure. A signal transducer and activator of transcription 3 (STAT3) promotes NPC oncogenesis through mechanisms within cancerous cells and their interactions with the tumor microenvironment, which is critical in the initiation, progression, and metastasis of NPC. Further, p-STAT3 is strongly associated with advanced NPC. Recent research on STAT3 has focused on its expression at the center of various oncogenic pathways. Here, we discuss the role of STAT3 in NPC and its potential therapeutic inhibitors and analogs for the treatment and control of NPC.

Nasopharyngeal Carcinoma Progression: Accumulating Genomic Instability and Persistent Epstein–Barr Virus Infection

Genomic instability facilitates the evolution of cells, tissues, organs, and species. The progression of human malignancies can be regarded as the accumulation of genomic instability, which confers a high evolutionary potential for tumor cells to adapt to continuous changes in the tumor microenvironment. Nasopharyngeal carcinoma (NPC) is a head-and-neck squamous-cell carcinoma closely associated with Epstein–Barr virus (EBV) infection. NPC progression is driven by a combination of accumulated genomic instability and persistent EBV infection. Here, we present a review of the key characteristics of genomic instability in NPC and the profound implications of EBV infection. We further discuss the significance of profiling genomic instability for the assessment of disease progression and treatment efficacy, as well as the opportunities and challenges of targeted therapies for NPC based on its unique genomic instability.

Advances in pathogenesis and precision medicine for nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a squamous carcinoma with apparent geographical and racial distribution, mostly prevalent in East and Southeast Asia, particularly concentrated in southern China. The epidemiological trend over the past decades has suggested a substantial reduction in the incidence rate and mortality rate due to NPC. These results may reflect changes in lifestyle and environment, and more importantly, a deeper comprehension of the pathogenic mechanism of NPC, leading to much progress in the preventing, screening, and treating for this cancer. Herein, we present the recent advances on the key signal pathways involved in pathogenesis of NPC, the mechanism of Epstein‐Barr virus (EBV) entry into the cell, and the progress of EBV vaccine and screening biomarkers. We will also discuss in depth the development of various therapeutic approaches including radiotherapy, chemotherapy, surgery, targeted therapy, and immunotherapy. These research advancements have led to a new era of precision medicine in NPC.

Epstein-Barr Virus Promotes Tumor Angiogenesis by Activating STIM1-Dependent Ca2+ Signaling in Nasopharyngeal Carcinoma

Epstein-Barr virus (EBV) promotes tumor angiogenesis in nasopharyngeal carcinoma (NPC) by activating store-operated Ca²⁺ entry. Since such entry has been linked to stromal interaction molecule 1 (STIM1), we examined whether the virus acts via STIM1-dependent Ca²⁺ signaling to promote tumor angiogenesis in NPC. STIM1 expression was detected in NPC cell lines HK1 and CNE2 that were negative or positive for EBV. STIM1 was knocked down in EBV-positive cells using recombinant lentivirus, then cytosolic Ca²⁺ levels were measured based on fluorescence resonance energy transfer. Cells were also exposed to epidermal growth factor (EGF), and secretion of vascular endothelial growth factor (VEGF) was measured using an enzyme-linked immunosorbent assay. Endothelial tube formation was quantified in an in vitro angiogenesis assay. Growth of CNE2-EBV xenografts was measured in mice, and angiogenesis was assessed based on immunohistochemical staining against CD31. Paraffin-embedded NPC tissues from patients were assayed for CD31 and STIM1. EGFR and ERK signaling pathways were assessed in NPC cell lines. STIM1 expression was higher in EBV-positive than in EBV-negative NPC cell lines. STIM1 knockdown in EBV-positive NPC cells significantly reduced Ca²⁺ influx and VEGF production after EGF treatment. STIM1 knockdown also inhibited xenograft growth and angiogenesis. Moreover, CD31 expression level was higher in EBV-positive than EBV-negative NPC tissues, and high expression of CD31 co-localized with high expression of STIM1 in EBV-positive tissues from NPC patients. Viral infection of NPC cells led to higher levels of phosphorylated ERK1/2 after EGF treatment, which STIM1 knockdown partially reversed. Our results suggest that EBV promotes EGF-induced ERK1/2 signaling by activating STIM1-dependent Ca²⁺ signaling, and that blocking such signaling may inhibit EBV-promoted angiogenesis in NPC.

(-)-Epigallocatechin-3-gallate inhibits EBV lytic replication via targeting LMP1-mediated MAPK signal axes

Epstein–Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) plays an important oncogenic role in the viral latent infection. Recently, increasing evidence indicates that the high expression of LMP1 during EBV lytic cycle is related to the viral lytic replication. However, the mechanism by which LMP1 regulates EBV lytic replication remains unclear. (−)-Epigallocatechin-3-gallate (EGCG) prevents carcinogenesis by directly targeting numerous membrane proteins and effectively inhibits EBV lytic cascade. Here, we demonstrated that LMP1 promotes EBV lytic replication through the downstream signal molecules MAPKs, including ERKs, p38, and JNKs. LMP1 induces the phosphorylation of p53 through MAPKs to enhance the ability of wild-type p53 (wt-p53) to activate expression of BZLF1 gene, while the JNKs/c-Jun signal axis appears to be involved in EBV lytic replication induced by LMP1 in p53 mutant manner. We provided the first evidence that EGCG directly targets the viral membrane LMP1 (K_d = 0.36 μM, n = 1) using fluorescence quenching, isothermal titration calorimetry (ITC) assay, and CNBR-activated Sepharose 4B pull-down affinity chromatography. Furthermore, we revealed that EGCG inhibits EBV lytic replication via suppressing LMP1 and thus blocking the downstream MAPKs/wt-p53 signal axis in AGS-EBV cells and JNKs/c-Jun signal axis in p53 mutant B95.8 cells. Our study, for the first time, reports the binding and inhibitory efficacy of EGCG to the LMP1, which is a key oncoprotein encoded by EBV. These findings suggest the novel function of LMP1 in the regulation of EBV lytic cycle and reveal the new role of EGCG in EBV-associated malignancies through suppressing viral reactivation.

EBV as a high infection risk factor promotes RASSF10 methylation and induces cell proliferation in EBV-associated gastric cancer

Epstein-Barr virus (EBV) is the first identified human tumor-related DNA virus, and has a high infection among people worldwide. Recent studies have showed that nearly 10% of gastric cancers have shown EBV infection and this kind of gastric cancer has been identified as a new subtype: EBV associated Gastric cancer (EBVaGC). Furthermore, it has been reported that tumor related genes in the EBVaGC showed frequent methylation modifications compared to those in the EBV negative gastric cancer (EBVnGC). To fully understand the role of EBV in EBVaGC, we analyzed and found that 16.67% of gastric carcinoma samples showed positive EBER1 signals. Mechanically, EBV-encoded Latent membrane protein 1 (LMP1) inhibited the expression of RASSF10, and promoted tumorigenesis by recruiting DNMT1 and inducing the DNA methylation of RASSF10. Altogether, it allows us a better understanding of the possible mechanism of EBV-induced gene hypermethylation in gastric cancer genome. Targeting EBV-induced DNA methylation is a potential therapeutic modality of EBVaGC.

Signaling pathways of EBV-induced oncogenesis

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.

Epstein-Barr Virus Mediated Signaling in Nasopharyngeal Carcinoma Carcinogenesis

Nasopharyngeal carcinoma (NPC) is one of the most common tumors occurring in China and Southeast Asia. Etiology of NPC seems to be complex and involves many determinants, one of which is Epstein-Barr virus (EBV) infection. Although evidence demonstrates that EBV infection plays a key role in NPC carcinogenesis, the exact relationship between EBV and dysregulation of signaling pathways in NPC needs to be clarified. This review focuses on the interplay between EBV and NPC cells and the corresponding signaling pathways, which are modulated by EBV oncoproteins and non-coding RNAs. These altered signaling pathways could be critical for the initiation and progression of NPC.

Epstein Barr Virus Associated Lymphomas and Epithelia Cancers in Humans

Epstein Barr virus (EBV) is a cosmopolitan oncogenic virus, infecting about 90% of the world's population and it is associated to tumors originating from both epithelia and hematopoietic cells. Transmission of the virus is mainly through oral secretions; however, transmission through organ transplantation and blood transfusion has been reported. In order to evade immune recognition, EBV establishes latent infection in B lymphocytes where it expresses limited sets of proteins called EBV transcription programs (ETPs), including six nuclear antigens (EBNAs), three latent membrane proteins (LMP), and untranslated RNA called EBV encoded RNA (EBER), shown to efficiently transform B cells into lymphoblastic cells. These programs undergo different patterns of expression which determine the occurrence of distinct types of latency in the pathogenesis of a particular tumor. Hematopoietic cell derived tumors include but not limited to Burkitt's lymphoma, Hodgkin lymphoma, post-transplant lymphoproliferative disorders, and natural killer (NK)/T cell lymphoma. EBV undergoes lytic infection in epithelia cells for amplification of the viral particle for transmission where it expresses lytic stage genes. However, for reasons yet to be unveiled, EBV switches from the expression of lytic stage genes to the expression of ETPs in epithelia cells. The expression of the ETPs lead to the transformation of epithelia cells into permanently proliferating cells, resulting in epithelia cell derived malignancies such as nasopharyngeal cancer, gastric cancer, and breast cancer. In this review, we have summarized the current updates on EBV associated epithelial and B cell-derived malignancies, and the role of EBV latency gene products in the pathogenesis of the cancers, and have suggested areas for future studies when considering therapeutic measures.

Nicotine Upregulates the Level of Mcl-1 through STAT3 in H1299 Cells

Background: Nicotine contributes to development of human lung cancer and chemoresistance through activation of myeloid cell leukemia-1 (Mcl-1). Signal transducer and activator of transcription 3 (STAT3) generally participates in development and progression of human cancers. Therefore, we examined the STAT3 cascade in nicotine regulation of Mcl-1 transcription in human lung cancer cells.

Methods: The effects of nicotine on the expression of STAT3 and Mcl-1 were determined using western blot. The sub-cellular localization was tested using immunofluorescence. The activity of STAT3 promoter was checked using dual luciferase reporter assay.

Results: STAT3 was constitutively activated (i.e., tyrosine-phosphorylated, serine-phosphorylated and nuclear translocation), meanwhile the expression and transcriptional activity of Mcl-1 were up-regulated in lung cancer cells following treatment with nicotine. Transfection with siRNA targeting STAT3 or treatment with STAT3 inhibitor JSI-124 diminished Mcl-1 protein levels. Deleted mutagenesis of a putative STAT3 consensus binding sequence decreased Mcl-1 promoter activity and eliminated the increase of Mcl-1 promoter activity induced by nicotine. Abnormally, JAK (Jannus kinase) inhibitor AG490 can't induce the downregulation of Mcl-1 or inhibit the tyrosine-phosphorylation of STAT3. In addition, deactivated mutagenesis of STAT3 the tyrosine 705 site had no effect on the aggregation of STAT3 into nucleus induced by nicotine.

Conclusions: We have demonstrated that nicotine induces up-regulation of Mcl-1 through STAT3, which process may be independent on JAKs and not only dependent on the phosphorylation of Y705. Downregulation of Mcl-1 transcription by inhibiting STAT3 cascade may be a potential strategy for the treatment of this cancer.

F factor plasmid-mediated Epstein-Barr virus genome introduction establishes an EBV positive NPC cell model

Background

Most Epstein-Barr virus (EBV)-positive cells lose the EBV episomes upon prolonged propagation.

Purpose

The purposes of this study were to establish a simple cell model for nasopharyngeal carcinoma (NPC) research by introducing a plasmid with the EBV genome into NPC cells and then to investigate the resulting changes in malignant biological behaviour and NPC-associated signalling pathways.

Methods

HONE1 NPC cells were transfected with F-factor plasmids including the EBV genome (HONE1-EBV cells). Then cell proliferation, migration, cell cycle distribution and apoptosis were evaluated in vitro by using CCK8, transwell and flow cytometry assays respectively. EBV-encoded proteins and cell signal tranducting proteins were detected by western blot assays. EBV-encoded RNAs were detected by in situ hybridization. EBV particles were assayed by transmission electron microscope (TEM). The morphology of cells were detected by immunofluorescence assays for alpha-tubulin.

Results

Latent membrane protein 1 (LMP1), latent membrane protein 2A (LMP2A), Epstein-Barr nuclear antigen 1 (EBNA1) and EBV-encoded small RNAs (EBERs) were successfully expressed in HONE1-EBV cells. No EBV particles were founded by TEM. Introduction of the EBV genome significantly promoted proliferation, cell cycle progression and migration and inhibited apoptosis in HONE1 cells. Immunofluorescence assays showed that the morphology of HONE1-EBV cells changed into spindle. Furthermore, EBV genome introduction significantly inhibited the JAK/STAT signalling pathway, while it activated the PI3K-AKT and NF-κB signalling pathways in HONE1 cells.

Conclusion

These findings suggest that F-factor plasmid-mediated EBV genome introduction was successful in constructing an EBV positive cell model, which showed deteriorated biological behavior and activated NPC-associated signalling pathways. This model can serve as a good tool for studying EBV in NPC, but the subtle differences in cancer-associated pathways must be considered.

Phosphorylated STAT3 expression predicts better prognosis in smoldering type of adult T-cell leukemia/lymphoma

Adult T‐cell leukemia/lymphoma (ATLL) is a mature T‐cell neoplasm, and is divided into 2 indolent (smoldering and chronic) and 2 aggressive (acute and lymphoma) clinical subtypes. Based on previous integrated molecular analyses suggesting the importance of the JAK‐STAT pathway in ATLL, we attempted to clarify the clinicopathological significance of this pathway. Clinical and morphological findings were reviewed in 116 cases with ATLL. The nuclear localizations of phosphorylated STAT3 (pSTAT3), pSTAT5, and pSTAT6 were analyzed by immunohistochemistry. Targeted sequencing was undertaken on the portion of STAT3 encoding the Src homology 2 domain. Expression of pSTAT3 was observed in 43% (50/116) of ATLL cases, whereas pSTAT5 and pSTAT6 were largely undetected. Cases with the lymphoma type showed significantly less frequent pSTAT3 expression (8/45, 18%) than those with the other subtypes (41/66, 62%; P < .001). STAT3 mutations were detected in 36% (10/28) and 19% (12/64) of cases with the smoldering and aggressive types of ATLL, respectively. The correlation between STAT3 mutation and pSTAT3 expression was not significant (P = .07). Both univariate and multivariate analysis revealed that pSTAT3 expression was significantly associated with better overall survival and progression‐free survival in the smoldering type of ATLL, whereas STAT3 mutation was not related to a line of clinical outcome. Collectively, our data show that only the lymphoma type showed a low prevalence of tumor cells positive for pSTAT3 expression, and raises the possibility that pSTAT3 expression is a novel biomarker to predict better prognosis in the smoldering type of ATLL.

The genomic landscape of Epstein-Barr virus-associated pulmonary lymphoepithelioma-like carcinoma

Pulmonary lymphoepithelioma-like carcinoma (LELC) is a rare and distinct subtype of primary lung cancer characterized by Epstein-Barr virus (EBV) infection. Herein, we reported the mutational landscape of pulmonary LELC using whole-exome sequencing, targeted deep sequencing and single-nucleotide polymorphism arrays. We identify a low degree of somatic mutation but widespread existence of copy number variations. We reveal predominant signature 2 mutations and frequent loss of type I interferon genes that are involved in the host-virus counteraction. Integrated analysis shows enrichment of genetic lesions affecting several critical pathways, including NF-κB, JAK/STAT, and cell cycle. Notably, multi-dimensional comparison unveils that pulmonary LELC resemble NPC but are clearly different from other lung cancers, natural killer/T-cell lymphoma or EBV-related gastric cancer in terms of genetic features. In all, our study illustrates a distinct genomic landscape of pulmonary LELC and provides a road map to facilitate genome-guided personalized treatment.

The rare lung cancer subtype pulmonary lymphoepithelioma-like carcinoma is linked to Epstein-Barr virus infection. Here, the authors provide a mutational landscape for this cancer, showing a low burden of somatic mutations and high prevalence of copy number variations.

Modulation of Angiogenic Processes by the Human Gammaherpesviruses, Epstein-Barr Virus and Kaposi's Sarcoma-Associated Herpesvirus

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.

Melanoma cell-secreted exosomal miR-155-5p induce proangiogenic switch of cancer-associated fibroblasts via SOCS1/JAK2/STAT3 signaling pathway

Background

Cancer-associated fibroblasts (CAFs) have been widely reported to promote tumor angiogenesis. However, the underlying mechanisms of the proangiogenic switch of CAFs remain poorly understood. This study aims to clarify the mechanisms underlying the proangiogenic switch of CAFs.

Methods

NIH/3T3 cells were treated with B16 and B16F10-derived exosomes. Then the CAFs markers and proangiogenic factors were detected by RT-PCR and Western blot. CCK-8 assay, transwell migration assay, tube formation assay, and in vivo Matrigel plug assay were conducted to determine the proangiogenic capability of CAFs. Western blot and AG490 were used to investigate the role of Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway in the proangiogenic switch of CAFs. Bioinformatics analysis, luciferase reporter assay, microRNA mimic and inhibitor, and xenograft models were used to investigate the role of mmu-miR-155-5p (miR-155) in the proangiogenic switch of CAFs.

Results

In this study, we show that melanoma cell-secreted exosomes can induce reprogramming of fibroblasts into CAFs and that exosomal miR-155 can trigger the proangiogenic switch of CAFs. Mechanistically exosomal miR-155 can be delivered into fibroblasts and promote the expression of proangiogenic factors, including vascular endothelial growth factor A (VEGFa), fibroblast growth factor 2 (FGF2), and matrix metalloproteinase 9 (MMP9), by directly targeting suppressor of cytokine signaling 1 (SOCS1). Downregulation of SOCS1 activates JAK2/STAT3 signaling pathway and elevates the expression levels of VEGFa, FGF2, and MMP9 in fibroblasts. Treatment with exosomes containing overexpressed miR-155 can promote angiogenesis, and the reduction of miR-155 in melanoma cell-secreted exosomes alleviates angiogenesis in vitro and in vivo.

Conclusions

These results demonstrate that by promoting the expression of proangiogenic factors in recipient fibroblasts via SOCS1/JAK2/STAT3 signaling pathway, melanoma cell-secreted exosomal miR-155 can induce the proangiogenic switch of CAFs. Although tumor angiogenesis is modulated by various factors, exosomal miR-155 may be a potential target for controlling melanoma angiogenesis and used to set up novel strategies to treat melanoma.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0911-3) contains supplementary material, which is available to authorized users.

STAT3 roles in viral infection: antiviral or proviral?

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor which can be activated by cytokines, growth factor receptors, and nonreceptor-like tyrosine kinase. An activated STAT3 translocates into the nucleus and combines with DNA to regulate the expression of target genes involved in cell proliferation, differentiation, apoptosis and metastasis. Recent studies have shown that STAT3 plays important roles in viral infection and pathogenesis. STAT3 exhibits a proviral function in several viral infections, including those of HBV, HCV, HSV-1, varicella zoster virus, human CMV and measles virus. However, in some circumstances, STAT3 has an antiviral function in other viral infections, such as enterovirus 71, severe acute respiratory syndrome coronavirus and human metapneumovirus. This review summarizes the roles of STAT3 in viral infection and pathogenesis, and briefly discusses the molecular mechanisms involved in these processes.

Topical Sunitinib ointment alleviates Psoriasis-like inflammation by inhibiting the proliferation and apoptosis of keratinocytes

Psoriasis is a chronic auto-immune inflammation disease with skin lesions and abnormal keratinocyte proliferation. Sunitinib, a multi-targeted tyrosine kinase inhibitor, is known to selectively inhibit several growth factor receptors, including vascular endothelial growth factor receptor, platelet-derived growth factor receptor and stem cell factor. It was reported that a patient with renal cell carcinoma (RCC) whose psoriatic lesion was resolved dramatically during treatment with Sunitinib, however, the mechanism is still unclear. We applied Sunitinib ointment to treat imiquimod-induced mouse model of psoriasis and found that Sunitinib ointment could alleviate imiquimod-induced psoriasis-like inflammation and reduce the Ki67 expression, while Sunitinib ointment couldn't reduce imiquimod-induced splenomegaly of the mouse model, then we concentrated on studying the effect of Sunitinib on the proliferation and apoptosis of keratinocytes, we cultivated HaCaT cells with epidermal growth factor (HaCaT/E cells) to represent as a state of highly proliferative psoriatic keratinocytes. We found that Sunitinib could inhibit the proliferation of Hacat/E cell in a time and concentration dependent manner by influencing the expression level of cell cycle protein D1, cycle protein E1, in addition, Sunitinib could induce the apoptosis of Hacat/E cell and up-regulate the expression of poly ADP-ribose polymerase (PARP). Sunitinib down-regulated the expression of phosphorylated signal transduction and activator of transcription 3 (p-Stat3) of Hacat/E cells significantly. We conclude that Sunitinib alleviates imiquimod-induced psoriasis-like inflammation by regulating the proliferation and apoptosis of HaCaT cells through inhibiting the expression of p-Stat3.

STAT3 mediates resistance to anoikis and promotes invasiveness of nasopharyngeal cancer cells

Nasopharyngeal carcinoma (NPC), a tumor arising from the epithelial cells of the nasopharynx, is endemic in Southeast Asia and Taiwan. The prognosis of NPC patients with local recurrence and metastasis is poor. Resistance to anoikis is a primary characteristic of tumor cells that metastasize. However, the mechanism through which NPC cells resist anoikis and are able to metastasize has not been fully elucidated. In the present study, the acquisition of anoikis resistance was analyzed in the TW01 and TW06 human NPC cell lines growing under anchorage-independent conditions. A considerable number of TW01 and TW06 cells was found to be resistant to anoikis and exhibited a higher capability of migration and invasion. These anoikis-resistant NPC cells exhibited significantly increased expression of signal transducer and activation of transcription 3 (Stat3) compared with adherent cells. Furthermore, blockade of STAT3 expression by STAT3 inhibitors or STAT3 silencing significant increased anoikis in anoikis-resistant NPC cells. Moreover, silencing STAT3 not only reduced the capacity of NPC cells to resist anoikis, but also reversed their invasive properties. The expression of epithelial‑to-mesenchymal transition‑related proteins and CD44 was also significantly decreased following STAT3 knockdown. The results of the present study established that STAT3 mediates anoikis resistance, with enhanced cell migration and invasion of NPC cells, and that activation of STAT3 may increase metastatic capacity, indicating the crucial role of STAT3 in conferring anoikis resistance and enhanced invasive properties to NPC cells.

STAT3 activation in infection and infection-associated cancer

The Janus kinase/signal transducers and activators for transcription (JAK/STAT) pathway plays crucial roles in regulating apoptosis, proliferation, differentiation, and the inflammatory response. The JAK/STAT families are composed of four JAK family members and seven STAT family members. STAT3 plays a key role in inducing and maintaining a pro-carcinogenic inflammatory microenvironment. Recent evidence suggests that STAT3 regulates diverse biological functions in pathogenesis of diseases, such as infection and cancer. In the current review, we will summarize the research progress of STAT3 activation in infection and cancers. We highlight our recent study on the novel role of STAT3 in Salmonella infection-associated colon cancer. Infection with bacterial AvrA-expressing Salmonella activates the STAT3 pathway, which induces the β-catenin signals and enhances colonic tumorigenesis. STAT3 may be a promising target in developing prevention and treatment for infectious diseases and infection-associated cancers.

Enhanced aerobic glycolysis of nasopharyngeal carcinoma cells by Epstein-Barr virus latent membrane protein 1

Latent membrane protein 1 (LMP1) is a principal viral oncoprotein in Epstein-Barr virus (EBV)-associated malignancies, including nasopharyngeal carcinoma (NPC), which acts through regulating tumorigenesis and metabolic reprogramming of cancers. In the presence of oxygen, we demonstrated that glucose consumption, lactate production and lactate dehydrogenase (LDH) activity were significantly increased upon LMP1 expression in NPC cells and in a LMP1 variant derived from NPC patients-transformed BALB/c-3T3 cells. The amounts of the α subunit of hypoxia-inducible factor-1 (HIF-1α), a key regulator of aerobic glycolysis, and its targets, pyruvate dehydrogenase kinase 1 (PDK1) and the pyruvate kinase M2 (PKM2) isoform, were also consistently elevated by LMP1. Moreover, in parallel with reductions in the oxygen consumption rate and mitochondrial membrane potential in cells, an augmented extracellular lactate concentration was observed due to LMP1 induction. In conclusion, our results proved facilitation of the Warburg effect by LMP1 through alteration of mitochondrial function in NPC cells.

Epstein-Barr Virus Latent Membrane Protein 2A (LMP2A) enhances IL-10 production through the activation of Bruton's tyrosine kinase and STAT3

Previous data demonstrate that Epstein-Barr Virus Latent Membrane Protein 2A (LMP2A) enhances IL-10 to promote the survival of LMP2A-expressing B cell lymphomas. Since STAT3 is an important regulator of IL-10 production, we hypothesized that LMP2A activates a signal transduction cascade that increases STAT3 phosphorylation to enhance IL-10. Using LMP2A-negative and -positive B cell lines, the data indicate that LMP2A requires the early signaling molecules of the Syk/RAS/PI3K pathway to increase IL-10. Additional studies indicate that the PI3K-regulated kinase, BTK, is responsible for phosphorylating STAT3, which ultimately mediates the LMP2A-dependent increase in IL-10. These data are the first to show that LMP2A signaling results in STAT3 phosphorylation in B cells through a PI3K/BTK-dependent pathway. With the use of BTK and STAT3 inhibitors to treat B cell lymphomas in clinical trials, these findings highlight the possibility of using new pharmaceutical approaches to treat EBV-associated lymphomas that express LMP2A.

Persistent Cytomegalovirus Infection in Amniotic Membranes of the Human Placenta

Human cytomegalovirus (HCMV) is the leading viral cause of birth defects, including microcephaly, neurological deficits, hearing impairment, and vision loss. We previously reported that epithelial cells in amniotic membranes of placentas from newborns with intrauterine growth restriction and underlying congenital HCMV infection contain viral proteins in cytoplasmic vesicles. Herein, we immunostained amniotic membranes from 51 placentas from symptomatic and asymptomatic congenital infection with HCMV DNA in amniotic fluid and/or newborn saliva, intrauterine growth restriction, preterm deliveries, and controls. We consistently observed HCMV proteins in amniotic epithelial cells (AmEpCs) from infected placentas, sometimes with aberrant morphology. Primary AmEpCs isolated from mid-gestation placentas infected with pathogenic VR1814 proliferated and released infectious progeny for weeks, producing higher virus titers than late-gestation cells that varied by donor. In contrast to intact virion assembly compartments in differentiated retinal pigment epithelial cells, infected AmEpCs made dispersed multivesicular bodies. Primary AmEpCs and explants of amniochorionic membranes from mid-gestation placentas formed foci of infection, and interferon-β production was prolonged. Infected AmEpCs up-regulated anti-apoptotic proteins survivin and Bcl-x_L by mechanisms dependent and independent of the activated STAT3. Amniotic membranes naturally expressed both survivin and Bcl-x_L, indicating that fetal membranes could foster persistent viral infection. Our results suggest strengthening innate immune responses and reducing viral functions could suppress HCMV infection in the fetal compartment.

A Central Role for STAT3 in Gammaherpesvirus-Life Cycle and -Diseases

Having co-evolved with humans, herpesviruses have adapted to exploit the host molecular machinery to ensure viral persistence. The cellular protein Signal Transducer and Activator of Transcription 3 (STAT3) is a leading example. STAT3 is a prominent transcription factor that functions in a variety of physiologic processes including embryonic development, inflammation, immunity, and wound healing. Generally activated via growth factor and cytokine signaling, STAT3 can transcriptionally drive oncoproteins, pro-survival and pro-proliferative proteins as well as angiogenic factors, thereby contributing to cancer. As in most non-viral cancers, STAT3 is constitutively active in EBV-related B and epithelial cell cancers and in animal models of KSHV-cancers. Again, similar to non-viral cancers, STAT3 contributes to gammaherpesvirus (EBV and KSHV)-mediated cancers by driving cell proliferation, invasion and angiogenesis. Being herpesviruses, EBV and KSHV establish latency in humans with episodic lytic activation. Importantly, both viruses activate STAT3 almost immediately upon infection of primary cells. In the setting of infection of primary B cells by EBV, this rapidly activated STAT3 plays a key role in suppressing the DNA damage response (DDR) to EBV-oncogene triggered replication stress, thereby facilitating B cell proliferation and ultimately establishment of latency. STAT3 also contributes to maintenance of latency by curbing lytic activation of EBV and KSHV in latent cells that express high levels of STAT3. In this way, gammaherpesviruses exploit STAT3 to overcome cellular anti-proliferative and anti-lytic barriers to promote viral persistence. These investigations into gammaherpesviruses and STAT3 have simultaneously revealed a novel function for STAT3 in suppression of the DDR, a process fundamental to physiologic cell proliferation as well as development of cancer.

Reduction of RKIP expression promotes nasopharyngeal carcinoma invasion and metastasis by activating Stat3 signaling

The role and underlying mechanism of Raf kinase inhibitory protein (RKIP) in nasopharyngeal carcinoma (NPC) metastasis remain unclear. Here, we showed that RKIP was downregulated in the NPC with high metastatic potentials, and its decrement correlated with NPC metastasis and poor patient survival, and was an independent predictor for reduced overall survival. With a combination of loss-of-function and gain-of-function approaches, we observed that high expression of RKIP reduced invasion, metastasis and epithelial to mesenchymal transition (EMT) marker alternations of NPC cells. We further showed that RKIP overexpression attenuated while RKIP knockdown enhanced Stat3 phosphorylation and activation in NPC cells; RKIP reduced Stat3 phosphorylation through interacting with Stat3; Stattic attenuated NPC cell migration, invasion and EMT marker alternations induced by RKIP knockdown, whereas Stat3 overexpression restored NPC cell migration, invasion and EMT marker alternations reduced by RKIP overexpression. In addition, there was an inverse correlation between RKIP and phospho-Stat3 expression in the NPC tissues and xenograft metastases. Our data demonstrate that RKIP is a metastatic suppressor and predictor for metastasis and prognosis in NPC, and RKIP downregulation promotes NPC invasion, metastasis and EMT by activating Stat3 signaling, suggesting that RKIP/Stat3 signaling could be used as a therapeutic target for NPC metastasis.

Vascular endothelial growth factor: an attractive target in the treatment of hypoxic/ischemic brain injury

Cerebral hypoxia or ischemia results in cell death and cerebral edema, as well as other cellular reactions such as angiogenesis and the reestablishment of functional microvasculature to promote recovery from brain injury. Vascular endothelial growth factor is expressed in the central nervous system after hypoxic/ischemic brain injury, and is involved in the process of brain repair via the regulation of angiogenesis, neurogenesis, neurite outgrowth, and cerebral edema, which all require vascular endothelial growth factor signaling. In this review, we focus on the role of the vascular endothelial growth factor signaling pathway in the response to hypoxic/ischemic brain injury, and discuss potential therapeutic interventions.

Functional characterization of TRPM7 in nasopharyngeal carcinoma and its knockdown effects on tumorigenesis

The aim of this study was to evaluate the association of functional expression of TRPM7 with nasopharyngeal carcinoma (NPC) growth. We examined the correlation of TRPM7 expression with cell growth and proliferation, cell cycle, and apoptosis in vitro in NPC cell lines and NPC tumorigenesis in mice by conducting experiments in mice and by further analyzing the tumor volume and growth. We further explored to see whether there is any positive correlation with the TRPM7 knockdown in NPC cells with their sensitivity to radiation. We found that the functional expression of TRPM7 in nasopharyngeal carcinoma is a critical requirement for physiological processes such as cell cycle, resistance to apoptosis, and cell proliferation. TRPM7 knockdown also enhanced sensitivity to radiotherapy of nasopharyngeal carcinoma. Moreover, we identified TRPM7 as a novel potential regulator of cell proliferation in NPC, through signal transducer and activator of transcription 3 (STAT3)-mediated signaling pathway and other anti-apoptotic factors. TRPM7 and STAT3 activation might be critical for the growth of NPC cells and could be an effective target for treatment of nasopharyngeal carcinoma.

The interplay of host genetic factors and Epstein-Barr virus in the development of nasopharyngeal carcinoma

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.

Novel roles and therapeutic targets of Epstein-Barr virus-encoded latent membrane protein 1-induced oncogenesis in nasopharyngeal carcinoma

Epstein-Barr virus (EBV) was first discovered 50 years ago as an oncogenic gamma-1 herpesvirus and infects more than 90% of the worldwide adult population. Nasopharyngeal carcinoma (NPC) poses a serious health problem in southern China and is one of the most common cancers among the Chinese. There is now strong evidence supporting a role for EBV in the pathogenesis of NPC. Latent membrane protein 1 (LMP1), a primary oncoprotein encoded by EBV, alters several functional and oncogenic properties, including transformation, cell death and survival in epithelial cells in NPC. LMP1 may increase protein modification, such as phosphorylation, and initiate aberrant signalling via derailed activation of host adaptor molecules and transcription factors. Here, we summarise the novel features of different domains of LMP1 and several new LMP1-mediated signalling pathways in NPC. When then focus on the potential roles of LMP1 in cancer stem cells, metabolism reprogramming, epigenetic modifications and therapy strategies in NPC.

The Complex Role of STAT3 in Viral Infections

Signal transducer and activators of transcription-3 (STAT3) regulates diverse biological functions including cell growth, differentiation, and apoptosis. In addition, STAT3 plays a key role in regulating host immune and inflammatory responses and in the pathogenesis of many cancers. Several studies reported differential regulation of STAT3 in a range of viral infections. Interestingly, STAT3 appears to direct seemingly contradictory responses and both pro- and antiviral roles of STAT3 have been described. This review summarized the currently known functions of STAT3 in the regulation of viral replication and pathogenesis of viral infections. Some of the key unanswered questions and the gap in our current understanding of the role of STAT3 in viral pathogenesis are discussed.

Reverse-Phase Microarray Analysis Reveals Novel Targets in Lymph Nodes of Bacillus anthracis Spore-Challenged Mice

Anthrax is a frequently fatal infection of many animal species and men. The causative agent Bacillus anthracis propagates through the lymphatic system of the infected host; however, the specific interactions of the host and microbe within the lymphatics are incompletely understood. We report the first description of the phosphoprotein signaling in the lymph nodes of DBA/2 mice using a novel technique combining the reverse-phase microarray with the laser capture microdissesction. Mice were challenged into foot pads with spores of toxinogenic, unencapsulated Sterne strain. The spores quickly migrated to the regional popliteal lymph nodes and spread to the bloodstream as early as 3 h post challenge. All mice died before 72 h post challenge from the systemic disease accompanied by a widespread LN tissue damage by bacteria, including the hemorrhagic necrotizing lymphadenitis, infiltration of CD11b+ and CD3+ cells, and massive proliferation of bacteria in lymph nodes. A macrophage scavenger receptor CD68/macrosialin was upregulated and found in association with vegetative bacteria likely as a marker of their prior interaction with macrophages. The major signaling findings among the 65 tested proteins included the reduced MAPK signaling, upregulation of STAT transcriptional factors, and altered abundance of a number of pro- and anti-apoptotic proteins with signaling properties opposing each other. Downregulation of ERK1/2 was associated with the response of CD11b+ macrophages/dendritic cells, while upregulation of the pro-apoptotic Puma indicated a targeting of CD3+ T-cells. A robust upregulation of the anti-apoptotic survivin was unexpected because generally it is not observed in adult tissues. Taken together with the activation of STATs it may reflect a new pathogenic mechanism aimed to delay the onset of apoptosis. Our data emphasize a notion that the net biological outcome of disease is determined by a cumulative impact of factors representing the microbial insult and the protective capacity of the host.

STAT3 inhibition reduces toxicity of oncolytic VSV and provides a potentially synergistic combination therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a refractory malignancy with a high mortality and increasing worldwide incidence rates, including the United States and central Europe. In this study, we demonstrate that a specific inhibitor of signal transducer and activator of transcription 3 (STAT3), NSC74859, efficiently reduces HCC cell proliferation and can be successfully combined with oncolytic virotherapy using vesicular stomatitis virus (VSV). The potential benefits of this combination treatment are strengthened by the ability of NSC74859 to protect primary hepatocytes and nervous system cells against virus-induced cytotoxicity, with an elevation of the VSV maximum tolerated dose in mice. Hereby we propose a strategy for improving the current regimen for HCC treatment and seek to further explore the molecular mechanisms underlying selective oncolytic specificity of VSV.

EBV-LMP1 targeted DNAzyme enhances radiosensitivity by inhibiting tumor angiogenesis via the JNKs/HIF-1 pathway in nasopharyngeal carcinoma

LMP1, which is encoded by the Epstein-Barr virus, is proposed to be one of the major oncogenic factors involved in nasopharyngeal carcinoma (NPC). Previous studies demonstrated that down-regulation of LMP1 by LMP1-targeted DNAzyme (DZ1) increases the radiosensitivity of NPC. However, the mechanism by which DZ1 contributes to this radiosensitivity remains unclear. In this study, we determined whether a DZ1 blockade of LMP1 expression has an overall positive effect on the radiotherapy of NPCs by repressing HIF-1/VEGF activity and to investigate the mechanisms underlying LMP1-induced HIF-1 activation in NPC cells. The results showed that DZ1 inhibited the microtubule-forming ability of HUVECs co-cultured with NPC cells, which occurs with the down-regulation of VEGF expression and secretion. Moreover, LMP1 increases phosphorylated JNKs/c-Jun signaling, which is involved in the regulation of HIF-1/VEGF activity. After silencing LMP1 and decreasing phosphorylation of JNKs, NPC cells exhibited an enhanced radiosensitivity. Furthermore, in vivo experiments revealed a significant inhibition of tumor growth and a marked reduction of the Ktrans parameter, which reflects the condition of tumor micro-vascular permeability. Taken together, our data suggested that VEGF expression is increased by LMP1 through the JNKs/c-Jun signaling pathway and indicated that DZ1 enhances the radiosensitivity of NPC cells by inhibiting HIF-1/VEGF activity.

Icaritin induces lytic cytotoxicity in extranodal NK/T-cell lymphoma

Background

Extranodal NK/T-cell lymphoma (ENKL) is an aggressive hematological malignancy associated with Epstein–Barr virus (EBV) infection. It is often resistant to conventional chemotherapy and has a poor prognosis. Icaritin, a compound derived from Chinese herbal medicine, Herba Epimedii, has been reported to exert antitumor effects on a variety of cancer cell lines. In the present study, we investigated the cytotoxic effects of Icaritin on the two EBV-positive ENKL cell lines SNK-10 and SNT-8, along with the underlying molecular mechanisms.

Methods

ENKL cell lines SNK-10 and SNT-8 were exposed to different concentrations of Icaritin for the indicated time. Treated cells were analyzed for cell proliferation, cell cycle, and cell apoptosis. Phosphorylation of Stat3 and Akt proteins in signaling pathways and the EBV-encoded LMP1 proteins were measured by Western blot. Expression of EBV genes was assessed by Real-Time PCR.

Results

Our results showed that Icaritin dose-dependently inhibits ENKL cell proliferation and induces apoptosis and cell cycle arrest at G₂/M phase. Additionally, Icaritin upregulates Bax, downregulates Bcl-2 and pBad, and activates caspase-3 and caspase-9. The anti-proliferative and pro-apoptotic effects of Icaritin are likely mediated by inhibition of Stat3 and Akt pathways through LMP1 downregulation. Importantly, Icaritin induces EBV lytic gene expression in ENKL cells, and the combination of Icaritin and the antiviral drug ganciclovir (GCV) is more effective in inducing ENKL cells apoptosis than Icaritin or GCV alone.

Conclusions

These findings indicate that EBV-targeted approaches may have significant therapeutic potential for ENKL treatment.

DCE-MRI assessment of the effect of Epstein-Barr virus-encoded latent membrane protein-1 targeted DNAzyme on tumor vasculature in patients with nasopharyngeal carcinomas

Background

EBV-encoded latent membrane protein 1 (EBV-LMP1) is an important oncogenic protein for nasopharyngeal carcinoma (NPC) and has been shown to engage a plethora of signaling pathways. Correspondingly, an LMP1-targeted DNAzyme was found to inhibit the growth of NPC cells both in vivo and in vitro by suppressing cell proliferation and inducing apoptosis. However, it remains unknown whether an LMP1-targeted DNAzyme would affect the vasculature of NPC. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has been applied in the clinical trials of anti-angiogenic drugs for more than ten years, and K^trans has been recommended as a primary endpoint. Therefore, the objective of the current study was to use DCE-MRI to longitudinally study the effect of an EBV-LMP1-targeted DNAzyme on the vasculature of patients with NPC.

Methods

Twenty-four patients were randomly divided into two groups: a combined treatment group (radiotherapy + LMP1-targeted DNAzyme) and a radiotherapy alone group (radiotherapy + normal saline). DCE-MRI scans were conducted 1 ~ 2 days before radiotherapy (Pre-RT), during radiotherapy (RT 50 Gy), upon completion of radiotherapy (RT 70 Gy), and three months after radiotherapy (3 months post-RT). Parameters of vascular permeability and intra- and extravascular volumes were subsequently obtained (e.g., K^trans, k_ep, v_e) using nordicICE software.

Results

Both K^trans and k_ep values for NPC tumor tissues decreased for both groups after treatment. Moreover, a statistically significant difference in K^trans values at the pre-therapy and post-therapy timepoints emerged earlier for the combined treatment group (RT 50 Gy, P =0.045) compared to the radiotherapy alone group (3 months post-RT, P = 0.032). For the k_ep values, the downward trend observed for both the combined treatment group and the radiotherapy alone group were similar. In contrast, v_e values for all of the tumor tissues increased following therapy.

Conclusions

The EBV-LMP1-targeted DNAzyme that was tested was found to accelerate the decline of K^trans values for patients with NPC. Correspondingly, the LMP1-targeted DNAzyme treatments were found to affect the angiogenesis and microvascular permeability of NPC.

Trial registration

ClinicalTrials.gov: NCT01449942. Registered 6 October 2011.

LMP1 stimulates the transcription of eIF4E to promote the proliferation, migration and invasion of human nasopharyngeal carcinoma

Eukaryotic translation initiation factor 4E (eIF4E) is the rate-limiting translation initiation factor for many oncogenes. Previous studies have shown eIF4E overexpression in nasopharyngeal carcinoma (NPC). We aimed to study whether viral oncogene latent membrane protein 1 (LMP1) stimulates the transcription of eIF4E to promote NPC malignancy. In NPC cell lines (CNE1 and CNE2), ectopic LMP1 significantly increased the mRNA and protein levels of eIF4E and the transcriptional activity of the eIF4E promoter in a LMP1-plasmid-transfected dose-dependent manner. As a backward experiment, knocking down of LMP1 significantly reduced eIF4E mRNA in B95-8 cells. In the high LMP1 expression condition, knocking down of c-Myc significantly reduced eIF4E mRNA in both NPC and B95-8 cells, and knocking down of eIF4E significantly inhibited the tumor proliferation, migration and invasion promoted by LMP1. The results indicated that LMP1 stimulates the transcription of eIF4E via c-Myc to promote NPC. To the best of our knowledge, this is the first evidence that LMP1 stimulates the transcription of eIF4E. This might be an important cause of the overexpression of eIF4E in NPC and be the novel mechanism by which LMP1 initiates cancer. LMP1-stimulated eIF4E initiates the translation of those oncogenes transcriptionally activated by LMP1 to amplify and pass down the carcinogenesis signals launched by LMP1.

Prevalence and clinical implications of epstein-barr virus infection in de novo diffuse large B-cell lymphoma in Western countries

PURPOSE

Epstein-Barr virus-positive (EBV(+)) diffuse large B-cell lymphoma (DLBCL) of the elderly is a variant of DLBCL with worse outcome that occurs most often in East-Asian countries and is uncommon in the Western hemisphere. We studied the largest cohort of EBV(+) DLBCL, independent of age, treated with rituximab combined with CHOP (R-CHOP) in developed Western countries.

EXPERIMENTAL DESIGN

A large cohort (n = 732) of patients with DLBCL treated with R-CHOP chemotherapy is included from the multicenter consortium. This study group has been studied for expression of different biomarkers by immunohistochemistry, genetic abnormalities by FISH and mutation analysis, genomic information by gene expression profiling (GEP), and gene set enrichment analysis (GSEA).

RESULTS

Twenty-eight patients (4.0%) were positive for EBV with a median age of 60.5 years. No clinical characteristics distinguished patients with EBV(+) DLBCL from patients with EBV-negative (EBV(-)) DLBCL. Genetic aberrations were rarely seen. NF-κB p50, phosphorylated STAT-3, and CD30 were more commonly expressed in EBV(+) DLBCLs (P < 0.05). Significant differences in survival were not observed in patients with EBV(+) DLBCL versus EBV(-) DLBCL. However, CD30 expression combined with EBV conferred an inferior outcome. GEP showed a unique expression signature in EBV(+) DLBCL. GSEA revealed enhanced activity of the NF-κB and JAK/STAT pathways independent of molecular subtype.

CONCLUSIONS

The clinical characteristics of patients with EBV(+) versus EBV(-) DLBCL are similar and EBV infection does not predict a worse outcome. EBV(+) DLBCL, however, has a unique genetic signature. CD30 expression is more common in EBV(+) DLBCL and, consistent CD30 and EBV is associated with an adverse outcome. Clin Cancer Res; 20(9); 2338-49. ©2014 AACR.