Decoy receptor 3, upregulated by Epstein-Barr virus latent membrane protein 1, enhances nasopharyngeal carcinoma cell migration and invasion

Copy Number Variations in Pancreatic Cancer: From Biological Significance to Clinical Utility

Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer, characterized by high tumor heterogeneity and a poor prognosis. Inter- and intra-tumoral heterogeneity in PDAC is a major obstacle to effective PDAC treatment; therefore, it is highly desirable to explore the tumor heterogeneity and underlying mechanisms for the improvement of PDAC prognosis. Gene copy number variations (CNVs) are increasingly recognized as a common and heritable source of inter-individual variation in genomic sequence. In this review, we outline the origin, main characteristics, and pathological aspects of CNVs. We then describe the occurrence of CNVs in PDAC, including those that have been clearly shown to have a pathogenic role, and further highlight some key examples of their involvement in tumor development and progression. The ability to efficiently identify and analyze CNVs in tumor samples is important to support translational research and foster precision oncology, as copy number variants can be utilized to guide clinical decisions. We provide insights into understanding the CNV landscapes and the role of both somatic and germline CNVs in PDAC, which could lead to significant advances in diagnosis, prognosis, and treatment. Although there has been significant progress in this field, understanding the full contribution of CNVs to the genetic basis of PDAC will require further research, with more accurate CNV assays such as single-cell techniques and larger cohorts than have been performed to date.

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.

Decoy Receptor 3 Expression Is Associated With Wild-Type EGFR Status, Poor Differentiation of Tumor, and Unfavorable Patient Outcome

OBJECTIVES

The role of decoy receptor 3 (DcR3) in lung cancer, particularly adenocarcinoma, has not been well studied. In this study, we aim to investigate the expression profile and the clinicopathologic implications of DcR3 expression in lung adenocarcinoma.

METHODS

Immunohistochemistry was used to examine DcR3 expression in 461 lung adenocarcinomas. The differences in DcR3 expression among the various histopathologic patterns were analyzed. The relationship between DcR3 expression and clinicopathologic parameters, including epidermal growth factor receptor (EGFR) mutation, was also investigated.

RESULTS

DcR3 expression was more frequently expressed in solid, micropapillary, and acinar patterns (P < .0001) and in tumors with wild-type EGFR status (P = .018). In addition, DcR3 expression portends a less favorable disease-free survival in stage I patients (P = .012).

CONCLUSIONS

The expression of DcR3 might be involved in the differentiation and progression of lung adenocarcinoma. Therefore, DcR3 may be applied clinically for prediction of tumor progression in stage I lung adenocarcinoma.

Hepatitis B X protein upregulates decoy receptor 3 expression via the PI3K/NF-κB pathway

Chronic hepatitis B (CHB) is associated with the development of hepatocellular carcinoma (HCC). Decoy receptor 3 (DcR3) is a tumor necrosis factor receptor that promotes tumor cell survival by inhibiting apoptosis and interfering with immune surveillance. Previous studies showed that DcR3 was overexpressed in HCC cells and that short hairpin RNA (shDcR3) sensitizes TRAIL-resistant HCC cells. However, the expression of DcR3 during hepatitis B virus (HBV) infection has not been investigated. Here, we demonstrated that DcR3 was overexpressed in CHB patients and that DcR3 upregulation was positively correlated with the HBV DNA load and liver injury (determined by histological activity index, serum alanine aminotransferase level, and aspartate aminotransferase level). We found that hepatitis B virus X protein (HBx) upregulated DcR3 expression in a dose-dependent manner, but this increase was blocked by NF-κB inhibitors. HBx also induced the activation of NF-κB, and the NF-κB subunits p65 and p50 upregulated DcR3 by directly binding to the DcR3 promoters. Inhibition of PI3K significantly downregulated DcR3 and inhibited the binding of NF-κB to the DcR3 promoters. Our results demonstrate that the HBx induced DcR3 expression via the PI3K/NF-κB pathway; this process may contribute to the development of HBV-mediated HCC.

Clinical significance of decoy receptor 3 upregulation in patients with hepatitis B and liver fibrosis

Decoy receptor 3 (DcR3) is a tumor necrosis factor receptor, which may inhibit apoptosis. The aim of the present study was to investigate the clinical significance of DcR3 upregulation in patients with chronic hepatitis B (CHB) and hepatic fibrosis. A total of 128 patients with a clinical diagnosis of CHB who underwent liver biopsy were included in the present study. The expression levels of DcR3, hyaluronic acid (HA), type III procollagen, type IV collagen (IV-C) and laminin protein were assessed. The diagnostic value of DcR3 in patients with CHB with hepatic fibrosis was determined using receiver operating characteristic (ROC) curve analysis. DcR3 was significantly upregulated in patients with CHB, particularly in patients with active CHB. The expression of DcR3 was significantly increased in patients with CHB with liver fibrosis and liver cirrhosis, compared with patients with CHB without liver fibrosis. The area under the ROC curve for the diagnosis of CHB liver fibrosis based on DcR3 or DcR3 combined with IV-C/HA was 0.807 or 0.869, with a sensitivity and specificity of 76.9 and 77.8% or 84.6 and 81.2%, respectively. DcR3 is a marker for liver fibrosis in patients with hepatitis B infection. The use of DcR3 in combination with IV-C and HA may further increase its diagnostic value for liver fibrosis.

The Microenvironment in Epstein-Barr Virus-Associated Malignancies

The Epstein–Barr virus (EBV) can cause a wide variety of cancers upon infection of different cell types and induces a highly variable composition of the tumor microenvironment (TME). This TME consists of both innate and adaptive immune cells and is not merely an aspecific reaction to the tumor cells. In fact, latent EBV-infected tumor cells utilize several specific mechanisms to form and shape the TME to their own benefit. These mechanisms have been studied largely in the context of EBV+ Hodgkin lymphoma, undifferentiated nasopharyngeal carcinoma, and EBV+ gastric cancer. This review describes the composition, immune escape mechanisms, and tumor cell promoting properties of the TME in these three malignancies. Mechanisms of susceptibility which regularly involve genes related to immune system function are also discussed, as only a small proportion of EBV-infected individuals develops an EBV-associated malignancy.

DcR3 induces epithelial-mesenchymal transition through activation of the TGF-β3/SMAD signaling pathway in CRC

Decoy receptor 3 (DcR3), a novel member of the tumor necrosis factor receptor (TNFR) family, was recently reported to be associated with tumorigenesis and metastasis. However, the role of DcR3 in human colorectal cancer (CRC) has not been fully elucidated. In this study, we found that DcR3 expression was significantly higher in human colorectal cancer tissues than in paired normal tissues, and that DcR3 expression was strongly correlated with tumor invasion, lymph node metastases and poor prognoses. Moreover, DcR3 overexpression significantly enhanced CRC cell proliferation and migration in vitro and tumorigenesis in vivo. Conversely, DcR3 knockdown significantly repressed CRC cell proliferation and migration in vitro, and DcR3 deficiency also attenuated CRC tumorigenesis and metastasis in vivo. Functionally, DcR3 was essential for TGF-β3/SMAD-mediated epithelial-mesenchymal transition (EMT) of CRC cells. Importantly, cooperation between DcR3 and TGF-β3/SMAD-EMT signaling-related protein expression was correlated with survival and survival time in CRC patients. In conclusion, our results demonstrate that DcR3 may be a prognostic biomarker for CRC and that this receptor facilitates CRC development and metastasis by participating in TGF-β3/SMAD-mediated EMT of CRC cells.

Decoy receptor 3: an endogenous immunomodulator in cancer growth and inflammatory reactions

Decoy receptor 3 (DcR3), also known as tumor necrosis factor receptor (TNFR) superfamily member 6b (TNFRSF6B), is a soluble decoy receptor which can neutralize the biological functions of three members of tumor necrosis factor superfamily (TNFSF): Fas ligand (FasL), LIGHT, and TL1A. In addition to ‘decoy’ function, recombinant DcR3.Fc is able to modulate the activation and differentiation of dendritic cells (DCs) and macrophages via ‘non-decoy’ action. DcR3-treated DCs skew T cell differentiation into Th2 phenotype, while DcR3-treated macrophages behave M2 phenotype. DcR3 is upregulated in various cancer cells and several inflammatory tissues, and is regarded as a potential biomarker to predict inflammatory disease progression and cancer metastasis. However, whether DcR3 is a pathogenic factor or a suppressor to attenuate inflammatory reactions, has not been discussed comprehensively yet. Because mouse genome does not have DcR3, it is not feasible to investigate its physiological functions by gene-knockout approach. However, DcR3-mediated effects in vitro are determined via overexpressing DcR3 or addition of recombinant DcR3.Fc fusion protein. Moreover, CD68-driven DcR3 transgenic mice are used to investigate DcR3-mediated systemic effects in vivo. Upregulation of DcR3 during inflammatory reactions exerts negative-feedback to suppress inflammation, while tumor cells hijack DcR3 to prevent apoptosis and promote tumor growth and invasion. Thus, ‘switch-on’ of DcR3 expression may be feasible for the treatment of inflammatory diseases and enhance tissue repairing, while ‘switch-off’ of DcR3 expression can enhance tumor apoptosis and suppress tumor growth in vivo.

Dendritic cells engineered to secrete anti-DcR3 antibody augment cytotoxic T lymphocyte response against pancreatic cancer in vitro

AIM

To investigate the enhanced cytotoxic T lymphocyte responses against pancreatic cancer (PC) in vitro induced by dendritic cells (DCs) engineered to secrete anti-DcR3 monoclonal antibody (mAb).

METHODS

DCs, T lymphocytes and primary PC cells were obtained from PC patients. DCs were transfected with a designed humanized anti-DcR3 monoclonal antibody heavy and light chain mRNA and/or total tumor RNA (DC-tumor-anti-DcR3 RNA or DC-total tumor RNA) by using electroporation technology. The identification, concentration and function of anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA were determined by western blotting and enzyme-linked immunosorbent assay. After co-culturing of autologous isolated PC cells with target DCs, the effects of secreting anti-DcR3 mAb on RNA-DCs’ viability and apoptosis were assessed by MTT assay and flow cytometry. Analysis of enhanced antigen-specific immune response against PC induced by anti-DcR3 mAb secreting DCs was performed using a ⁵¹Cr releasing test. T cell responses induced by RNA-loaded DCs were analyzed by measuring cytokine levels, including IFN-γ, IL-10, IL4, TNF-α and IL-12.

RESULTS

The anti-DcR3 mAb secreted by DCs reacted with recombinant human DcR3 protein and generated a band with 35 kDa molecular weight. The secreting mAb was transient, peaking at 24 h and becoming undetectable after 72 h. After co-incubation with DC-tumor-anti-DcR3 RNA for designated times, the DcR3 level in the supernatant of autologous PC cells was significantly down-regulated (P < 0.05). DCs secreting anti-DcR3 mAb could improve cell viability and slow down the apoptosis of RNA-loaded DCs, compared with DC-total tumor RNA (P < 0.01). The anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA could enhance the induction of cytotoxic T lymphocytes (CTLs) activity toward RNA-transfected DCs, primary tumor cells, and PC cell lines, compared with CTLs stimulated by DC-total tumor RNA or control group (P < 0.05). Meanwhile, the antigen-specific CTL responses were MHC class I-restricted. The CD4+ T cells and CD8+ T cells incubated with anti-DcR3 mAb secreting DCs could produce extremely higher level IFN-γ and lower level IL4 than those incubated with DC-total tumor RNA or controls (P < 0.01).

CONCLUSION

DCs engineered to secrete anti-DcR3 antibody can augment CTL responses against PC in vitro, and the immune-enhancing effects may be partly due to their capability of down-regulating DC apoptosis and adjusting the Th1/Th2 cytokine network.

Pre-treatment serum inflammatory cytokines as survival predictors of patients with nasopharyngeal carcinoma receiving chemoradiotherapy

The present study aimed to examine the predictability of pre-treatment serum levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α for determining the outcome of patients with nasopharyngeal carcinoma (NPC) assigned for chemoradiotherapy. A total of 35 patients with NPC were subjected to clinical examination and evaluation of performance status using Karnofsky scoring. Nasopharyngoscopy was performed for evaluation and to obtain a biopsy. Blood samples were obtained pre- and post-treatment for polymerase chain reaction quantitative estimation of Epstein-Barr virus (EBV) DNA plasma load and enzyme-linked immunosorbent assay for estimation of serum cytokines. All patients received chemoradiotherapy and were followed-up for 2 years. Cervical lymphadenopathy and recurrent attacks of epistaxis are the most common presenting symptoms. Treatment significantly decreased pre-treatment plasma EBV DNA load and serum levels of IL-6 and TNF-α, and increased serum IL-1β levels. Clinical staging and EBV DNA plasma load revealed positively significant correlation with pre-treatment serum levels of both IL-6 and TNF-α, while revealed negative significant correlation with serum IL-1β levels. The 2-year survival rate was negatively significantly correlated with pre-treatment levels of IL-6 and TNF-α, and EBV DNA viral load, while it was positively significantly correlated with pre-treatment performance scores and serum IL-1β levels. Statistical analyses defined high pre-treatment serum IL-6 levels as a significant specific predictor for high mortality rate. It was demonstrated that NPC was associated with high pre-treatment plasma EBV DNA load and serum cytokines, and chemoradiotherapy significantly reduced these high levels. High pre-treatment serum IL-6 level was a significant specific predictor for high mortality rate. Increased post-treatment serum levels of IL-1β indicated good therapeutic response and most probably a high survival rate.

Idiopathic pulmonary fibrosis fibroblasts become resistant to Fas ligand-dependent apoptosis via the alteration of decoy receptor 3

Idiopathic pulmonary fibrosis (IPF) is an irreversible lethal lung disease with an unknown etiology. IPF patients' lung fibroblasts express inappropriately high Akt activity, protecting them in response to an apoptosis-inducing type I collagen matrix. FasL, a ligand for Fas, is known to be increased in the lung tissues of patients with IPF, implicated with the progression of IPF. Expression of Decoy Receptor3 (DcR3), which binds to FasL, thereby subsequently suppressing the FasL-Fas-dependent apoptotic pathway, is frequently altered in various human disease. However, the role of DcR3 in IPF fibroblasts in regulating their viability has not been examined. We found that enhanced DcR3 expression exists in the majority of IPF fibroblasts on collagen matrices, resulting in the protection of IPF fibroblasts from FasL-induced apoptosis. Abnormally high Akt activity suppresses GSK-3β function, thereby accumulating the nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) in the nucleus, increasing DcR3 expression in IPF fibroblasts. This alteration protects IPF cells from FasL-induced apoptosis on collagen. However, the inhibition of Akt or NFATc1 decreases DcR3 mRNA and protein levels, which sensitizes IPF fibroblasts to FasL-mediated apoptosis. Furthermore, enhanced DcR3 and NFATc1 expression is mainly present in myofibroblasts in the fibroblastic foci of lung tissues derived from IPF patients. Our results showed that when IPF cells interact with collagen matrix, aberrantly activated Akt increases DcR3 expression via GSK-3β-NFATc1 and protects IPF cells from the FasL-dependent apoptotic pathway. These findings suggest that the inhibition of DcR3 function may be an effective approach for sensitizing IPF fibroblasts in response to FasL, limiting the progression of lung fibrosis. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Viral Carcinogenesis Beyond Malignant Transformation: EBV in the Progression of Human Cancers

Cancer progression begins when malignant cells colonize adjacent sites, and it is characterized by increasing tumor heterogeneity, invasion and dissemination of cancer cells. Clinically, progression is the most relevant stage in the natural history of cancers. A given virus is usually regarded as oncogenic because of its ability to induce malignant transformation of cells. Nonetheless, oncogenic viruses may also be important for the progression of infection-associated cancers. Recently this hypothesis has been addressed because of studies on the contribution of the Epstein-Barr virus (EBV) to the aggressiveness of nasopharyngeal carcinoma (NPC). Several EBV products modulate cancer progression phenomena, such as the epithelial-mesenchymal transition, cell motility, invasiveness, angiogenesis, and metastasis. In this regard, there are compelling data about the effects of EBV latent membrane proteins (LMPs) and EBV nuclear antigens (EBNAs), as well as nontranslated viral RNAs, such as the EBV-encoded small nonpolyadenylated RNAs (EBERs) and viral microRNAs, notably EBV miR-BARTs. The available data on the mechanisms and players involved in the contribution of EBV infection to the aggressiveness of NPC are discussed in this review. Overall, this conceptual framework may be valuable for the understanding of the contribution of some infectious agents in the progression of cancers.

LMP1 promotes nasal NK/T-cell lymphoma cell function by eIF4E via NF-κB pathway

Nasal natural killer T-cell lymphoma (NKTL) is a highly malignant tumor that is closely associated with Epstein-Barr virus (EBV) infection. Latent membrane protein 1 (LMP1) is encoded by EBV and plays an important role in EBV-induced cell transformation. Therefore, we assessed the function of LMP1 as a stimulant of NKTL progression and the underlying mechanism. A human EBV-positive NKTL cell line (SNK-6) was transfected with pcDNA3.1-LMP1, LV-LMP1 shRNA or LV-eukaryotic translation initiation factor 4E (eIF4E)-shRNA. Then, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to assess the proliferation of SNK-6 cells, and cell migration and invasion were analyzed by transwell chamber assay. Flow cytometry was used to analyze the cell cycle and apoptosis. The results showed LMP1 was highly expressed in SNK-6 cells compared with control groups. Following pretreatment with LMP1 shRNA, the proliferation of SNK-6 cells was inhibited and resulted in a G0/G1 phase arrest. A reduction in invasion and migration was also observed. LMP1 silencing promoted cell apoptosis. Further mechanistic analysis suggested that LMP1 overexpression induced the expression of eIF4E, while eIF4E-shRNA dramatically attenuated the increase in cell proliferation, invasion, migration and the inhibition of apoptosis triggered by LMP-1 upregulation. Moreover, the effect of LMP1 on eIF4E expression was mediated by the NF-κB pathway. Therefore, this finding may provide a potential target against NKTL.

WTC-01, a novel synthetic oxime-flavone compound, destabilizes microtubules in human nasopharyngeal carcinoma cells in vitro and in vivo

BACKGROUND AND PURPOSE

Dynamic polymerization of microtubules is essential for cancer cell growth and metastasis, and microtubule-disrupting agents have become the most successful anti-cancer agents in clinical use. Besides their antioxidant properties, flavonoids also exhibit strong microtubule-disrupting activity and inhibit tumour growth. We have designed, synthesized and tested a series of oxime/amide-containing flavone derivatives. Here we report the evaluation of one compound, WTC-01 for its anti-proliferative effects in human cancer cells.

EXPERIMENTAL APPROACH

We used a range of cancer cell lines including two human nasopharyngeal carcinoma (NPC) cell lines, measuring proliferation, cell cycle and apoptosis, along with caspase levels and mitochondrial membrane potentials. Assays of tubulin polymerisation in vitro and computer modelling of the colchicine binding site in tubulin were also used. In mice, pharmacokinetics and growth of NPC-derived tumours were studied.

KEY RESULTS

WTC-01 was most potent against proliferation of NPC cells (IC50 = 0.45 μM), inducing accumulation of cells in G2 /M and increasing apoptosis, time- and concentration-dependently. The colchicine competition-binding experiments and computer modelling results suggested that WTC-01 causes microtubule disruption via binding to the colchicine-binding site of tubulin resulting in mitochondrial membrane damage and cell apoptosis via activation of caspase-9/-3 without noticeable activation of the caspase-8. Notably, our in vivo studies demonstrated that at doses of 25 and 50 mg·kg(-1) , WTC-01 exhibited good pharmacokinetic properties and completely inhibited the growth of NPC-TW01 cells in a xenograft nude mouse model.

CONCLUSIONS AND IMPLICATIONS

WTC-01, a new synthetic oxime-containing flavone, exhibited potent anti-tumour activity against NPC cells and merits further investigation.

Understanding the interplay between host immunity and Epstein-Barr virus in NPC patients

Epstein-Barr virus (EBV) has been used as a paradigm for studying host-virus interactions, not only because of its importance as a human oncogenic virus associated with several malignancies including nasopharyngeal carcinoma (NPC) but also owing to its sophisticated strategies to subvert the host antiviral responses. An understanding of the interplay between EBV and NPC is critical for the development of EBV-targeted immunotherapy. Here, we summarize the current knowledge regarding the host immune responses and EBV immune evasion mechanisms in the context of NPC.

The tumor marker Fascin is induced by the Epstein-Barr virus-encoded oncoprotein LMP1 via NF-κB in lymphocytes and contributes to their invasive migration

Background

The actin-bundling protein Fascin (FSCN1) is a tumor marker that is highly expressed in numerous types of cancer including lymphomas and is important for migration and metastasis of tumor cells. Fascin has also been detected in B lymphocytes that are freshly-infected with Epstein-Barr virus (EBV), however, both the inducers and the mechanisms of Fascin upregulation are still unclear.

Results

Here we show that the EBV-encoded oncoprotein latent membrane protein 1 (LMP1), a potent regulator of cellular signaling and transformation, is sufficient to induce both Fascin mRNA and protein in lymphocytes. Fascin expression is mainly regulated by LMP1 via the C-terminal activation region 2 (CTAR2). Block of canonical NF-κB signaling using a chemical inhibitor of IκB kinase β (IKKβ) or cotransfection of a dominant-negative inhibitor of IκBα (NFKBIA) reduced not only expression of p100, a classical target of the canonical NF-κB-pathway, but also LMP1-induced Fascin expression. Furthermore, chemical inhibition of IKKβ reduced both Fascin mRNA and protein levels in EBV-transformed lymphoblastoid cell lines, indicating that canonical NF-κB signaling is required for LMP1-mediated regulation of Fascin both in transfected and transformed lymphocytes. Beyond that, chemical inhibition of IKKβ significantly reduced invasive migration of EBV-transformed lymphoblastoid cells through extracellular matrix. Transient transfection experiments revealed that Fascin contributed to LMP1-mediated enhancement of invasive migration through extracellular matrix. While LMP1 enhanced the number of invaded cells, functional knockdown of Fascin by two different small hairpin RNAs resulted in significant reduction of invaded, non-attached cells.

Conclusions

Thus, our data show that LMP1-mediated upregulation of Fascin depends on NF-κB and both NF-κB and Fascin contribute to invasive migration of LMP1-expressing lymphocytes.

The soluble Decoy Receptor 3 is regulated by a PI3K-dependent mechanism and promotes migration and invasion in renal cell carcinoma

Background

Overexpression of Decoy Receptor 3 (DcR3), a soluble member of the tumor necrosis factor receptor superfamily, is a common event in several types of cancer. In renal cell carcinoma (RCC), DcR3 overexpression is associated with lymph node and distant metastasis as well as a poor prognosis. However, the functional role and regulation of DcR3 expression in RCC is so far unknown.

Methods

Modulation of DcR3 expression by siRNA and ectopic gene expression, respectively, was performed in ACHN and 769-P RCC cell lines. Functional effects of a modulated DcR3 expression were analyzed with regard to migration, invasion, adhesion, clonogenicity, and proliferation. Furthermore, quantitative RT-PCR and immunoblot analyses were performed to evaluate the expression of downstream mediators of DcR3. In further experiments, luciferase assays, quantitative RT-PCR and immunoblot analyses were applied to study the regulation of DcR3 expression in RCC. Additionally, an ex vivo tissue slice culture technique combined with immunohistochemistry was used to study the regulation of DcR3 expression in human RCC specimens.

Results

Here, we show that DcR3 promotes adhesion, migration and invasiveness of RCC cells. The DcR3-dependent increase in cellular invasiveness is accompanied with an up-regulation of integrin alpha 4, matrixmetalloproteinase 7 and urokinase plasminogen activator (uPA). Further, we identified a signaling pathway regulating DcR3 expression in RCC. Using in vitro experiments as well as an ex vivo RCC tissue slice culture model, we demonstrate that expression of DcR3 is regulated in a PI3K/AKT-dependent manner involving the transcription factor nuclear factor of activated T-cells (NFAT).

Conclusions

Taken together, our results identify DcR3 as a key driver of tumor cell dissemination and suggest DcR3 as a promising target for rational therapy of RCC.

'Decoy' and 'non-decoy' functions of DcR3 promote malignant potential in human malignant fibrous histiocytoma cells

Decoy receptor 3 (DcR3) is a soluble secreted protein that belongs to the tumor necrosis factor receptor (TNFR) superfamily. DcR3 inhibits the Fas ligand (FasL)/Fas apoptotic pathway by binding to FasL, competitively with Fas receptor. Previous studies have reported that overexpression of DcR3 has been detected in various human malignancies and that DcR3 functions as a ‘decoy’ for FasL to inhibit FasL-induced apoptosis. In addition, recent studies have revealed that DcR3 has ‘non-decoy’ functions to promote tumor cell migration and invasion, suggesting that DcR3 may play important roles in tumor progression by decoy and non-decoy functions. We have previously reported that overexpression of DcR3 was observed in human malignant fibrous histiocytoma (MFH), however, the roles of DcR3 in MFH have not been studied. In the present study, to elucidate the roles of DcR3 in tumor progression of MFH, we examined the effects of DcR3 inhibition on cell apoptosis, migration and invasion in human MFH cells. siRNA knockdown of DcR3 enhanced the FasL-induced apoptotic activity and significantly decreased cell migration and invasion with a decrease in the activation of phosphatidylinositol 3 kinase (PI3K)/Akt and matrix metalloproteinase (MMP)-2. The findings in this study strongly suggest that DcR3 plays important roles in tumor progression of human MFH by decoy as well as non-decoy functions and that DcR3 may serve as a potent therapeutic target for human MFH.

LMP1 and LMP2A are potential prognostic markers of extranodal NK/T-cell lymphoma, nasal type (ENKTL)

Background

Latent membrane protein (LMP) 1 and LMP2A encoded by Epstein-Barr virus (EBV) are associated with the development of malignancies, but their expression in extranodal NK/T-cell lymphoma, nasal type (ENKTL) and the relationship with clinical characteristics of this disease remain poorly understood. In the present study, we examined the expression of LMP1 and LMP2A in ENKTL, and investigated the correlations between LMP1 and LMP2A expression with clinicopathological characteristics of ENKTL patients.

Methods

Paraffin sections of surgically removed samples from 16 ENKTL patients were analyzed by immunohistochemistry and the related clinicopathological data were collected and analyzed.

Results

Elevated expression (immunohistochemistry score ≥ 4) of LMP1 and LMP2A was detected in the tumor cells of ENKTL. High LMP1 expression was associated with positive B symptoms (p = 0.012), while high LMP2A expression was related to gender (p = 0.029). The expression of both LMP1 and LMP2A showed significant correlations with patients’ overall survival (p = 0.049, p = 0.036).

Conclusion

LMP1 and LMP2A may be prognostic indicators of survival in patients with ENKTL.

Virtual slides

http://www.diagnosticpathology.diagnomx.eu/vs/2443352538545899

Involvement of recepteur d'origine nantais receptor tyrosine kinase in Epstein-Barr virus-associated nasopharyngeal carcinoma and its metastasis

Nasopharyngeal carcinoma (NPC) is characteristic for its strong association with Epstein-Barr virus (EBV) and high metastatic rate. Recently, overexpressed recepteur d'origine nantais (RON) (MST1R), receptor tyrosine kinase has been reported in human cancers and tumor metastasis. Therefore, the role of RON in EBV-associated NPC and its metastasis was investigated. Here we show that RON was found in NPC but not in control tissues. A significant correlation of latent membrane protein 1 (LMP1) and RON expression was found in NPC (Pearson's χ(2) test; P = 0.0023). At the molecular level, LMP1 stimulates nuclear factor-κB binding to the RON promoter through its carboxyl-terminal activation region 1 to induce expression of RON. Knockdown of RON in cells expressing LMP1 significantly reverses LMP1-induced epithelial-mesenchymal transition and suppresses LMP1-induced cell migration and invasion. These results suggest an important role of RON in the tumorigenesis and metastasis of NPC and RON may be a novel therapeutic target for EBV-associated NPC.

A novel LMP1 antibody synergizes with mitomycin C to inhibit nasopharyngeal carcinoma growth in vivo through inducing apoptosis and downregulating vascular endothelial growth factor

Combined therapy emerges as an attractive strategy for cancer treatment. The aim of this study was to investigate the inhibitory effects of mitomycin C (MMC) combined with a novel antibody fragment (Fab) targeting latent membrane protein 1 (LMP1) on nasopharyngeal carcinoma (NPC) xenograft nude mice. The inhibitory rates of MMC (2 mg/kg), Fab (4 mg/kg), MMC (2 mg/kg) + Fab (4 mg/kg), and MMC (1 mg/kg) + Fab (4 mg/kg) were 20.1%, 7.3%, 42.5% and 40.5%, respectively. Flow cytometry analysis showed that the apoptotic rate of xenograft tumor cells in the MMC and Fab combination group was 28 ± 4.12%, significantly higher than the MMC (2 mg/kg) group (P < 0.01). Immunohistochemical staining showed that VEGF expression in NPC xenografts was significantly inhibited in the combination group compared to the Fab (4 mg/kg) group (P < 0.05). In conclusion, both MMC and Fab could inhibit NPC xenograft tumor growth in vivo and combination therapy showed apparent synergistic anti-tumor effects, which may be due to the induction of tumor cell apoptosis and the downregulation of VEGF expression. These results suggest that the novel combined therapy utilizing traditional chemotherapeutics and antibody-targeted therapy could be a promising strategy for the treatment of NPC.

Decoy receptor 3 inhibits renal mononuclear leukocyte infiltration and apoptosis and prevents progression of IgA nephropathy in mice

The progression of IgA nephropathy (IgAN), the most frequent type of primary glomerulonephritis, is associated with high levels of mononuclear leukocyte infiltration into the kidney. These cells consist mainly of T cells and macrophages. Our previous study showed that a decoy receptor 3 (DCR3) gene therapy can prevent the development of a mouse autoimmune glomerulonephritis model by its potent immune modulating effects (Ka SM, Sytwu HK, Chang DM, Hsieh SL, Tsai PY, Chen A. J Am Soc Nephrol 18: 2473-2485, 2007). Here, we tested the hypothesis that DCR3 might prevent the progression of IgAN, an immune complex-mediated primary glomerulonephritis, by inhibiting T cell activation, renal T cell/macrophage infiltration, and protecting the kidney from apoptosis. We used a progressive IgAN (Prg-IgAN) model in B cell-deficient mice, because the mice are characterized by a dramatic proliferation of activated T cells systemically and progressive NF-κB activation in the kidney. We treated the animals with short-term gene therapy with DCR3 plasmids by hydrodynamics-based gene delivery. When the mice were euthanized on day 21, we found that, compared with empty vector-treated (disease control) Prg-IgAN mice, DCR3 gene therapy resulted in 1) systemic inhibition of T cell activation and proliferation; 2) lower serum levels of proinflammatory cytokines; 3) improved proteinuria, renal function, and renal pathology (inhibiting the development of marked glomerular proliferation, crescent formation, glomerulosclerosis, and interstitial inflammation); 5) suppression of T cell and macrophage infiltration into the periglomerular interstitium of the kidney; and 5) a reduction in apoptotic figures in the kidney. On the basis of these findings, DCR3 might be useful therapeutically in preventing the progression of IgAN.

Association between genetic subgroups of pancreatic ductal adenocarcinoma defined by high density 500 K SNP-arrays and tumor histopathology

The specific genes and genetic pathways associated with pancreatic ductal adenocarcinoma are still largely unknown partially due to the low resolution of the techniques applied so far to their study. Here we used high-density 500 K single nucleotide polymorphism (SNP)-arrays to define those chromosomal regions which most commonly harbour copy number (CN) alterations and loss of heterozygozity (LOH) in a series of 20 PDAC tumors and we correlated the corresponding genetic profiles with the most relevant clinical and histopathological features of the disease. Overall our results showed that primary PDAC frequently display (>70%) extensive gains of chromosomes 1q, 7q, 8q and 20q, together with losses of chromosomes 1p, 9p, 12q, 17p and 18q, such chromosomal regions harboring multiple cancer- and PDAC-associated genes. Interestingly, these alterations clustered into two distinct genetic profiles characterized by gains of the 2q14.2, 3q22.1, 5q32, 10q26.13, 10q26.3, 11q13.1, 11q13.3, 11q13.4, 16q24.1, 16q24.3, 22q13.1, 22q13.31 and 22q13.32 chromosomal regions (group 1; n = 9) versus gains at 1q21.1 and losses of the 1p36.11, 6q25.2, 9p22.1, 9p24.3, 17p13.3 and Xp22.33 chromosomal regions (group 2; n = 11). From the clinical and histopathological point of view, group 1 cases were associated with smaller and well/moderately-differentiated grade I/II PDAC tumors, whereas and group 2 PDAC displayed a larger size and they mainly consisted of poorly-differentiated grade III carcinomas. These findings confirm the cytogenetic complexity and heterogenity of PDAC and provide evidence for the association between tumor cytogenetics and its histopathological features. In addition, we also show that the altered regions identified harbor multiple cancer associate genes that deserve further investigation to determine their relevance in the pathogenesis of PDAC.

Decoy receptor 3: a pleiotropic immunomodulator and biomarker for inflammatory diseases, autoimmune diseases and cancer

Recently, several decoy molecules belonging to tumor necrosis factor receptor superfamily (TNFRSF) have been identified, including decoy receptor 1 (DcR1), decoy receptor 2 (DcR2), and decoy receptor 3 (DcR3). One of the tumor necrosis factor superfamily (TNFSF) members, TNF-related apoptosis-inducing ligand (TRAIL), binds to DcR1 and DcR2, which are membranous receptors with a truncated cytoplasmic domain, thus unable to transduce TRAIL-mediated signaling. In contrast to DcR1 and DcR2, DcR3 is a soluble receptor capable of neutralizing the biological effects of three other TNFSF members: Fas ligand (FasL/TNFSF6/CD95L), LIGHT (TNFSF14) and TNF-like molecule 1A (TL1A/TNFSF15). Since FasL is a potent apoptosis- and inflammation-inducing factor, LIGHT is involved in apoptosis and inflammation, and TL1A is a T cell costimulator and is involved in gut inflammation, DcR3 can be defined as an immunomodulator on the basis of its neutralizing effects on FasL, LIGHT, and TL1A. Initial studies demonstrated that DcR3 expression is elevated in tumors cells; however, later work showed that DcR3 expression is also upregulated in inflammatory diseases, where serum DcR3 levels correlate with disease progression. In addition to its neutralizing effect, DcR3 also acts as an effector molecule to modulate cell function via 'non-decoy' activities. This review focuses on the immunomodulatory effects of DcR3 via 'decoy' and 'non-decoy' functions, and discusses the potential of DcR3 as a biomarker to predict cancer invasion and inflammation progression. We also discuss the possible utility of recombinant DcR3 as a therapeutic agent to control autoimmune diseases, as well as the potential to attenuate tumor progression by inhibiting DcR3 expression.

Aberrant expression and function of death receptor-3 and death decoy receptor-3 in human cancer

Death receptor-3 (DR3) and death decoy receptor-3 (DcR3) are both members of the tumour necrosis factor receptor (TNFR) superfamily. The TNFR superfamily contains eight death domain-containing receptors, including TNFR1 (also called DR1), Fas (also called DR2), DR3, DR4, DR5, DR6, NGFR and EDAR. Upon the binding of these receptors with their corresponding ligands, the death domain recruits various proteins that mediate both the death and proliferation of cells. Receptor function is negatively regulated by decoy receptors (DcR1, DcR2, DcR3 and OPG). DR3/DcR3 are a pair of positive and negative players with which vascular endothelial growth inhibitor (VEGI) interacts. VEGI has been suggested to be a potential tumour suppressor. The inhibitory effects of VEGI on cancer are manifested in three main areas: a direct effect on cancer cells, an anti-angiogenic effect on endothelial cells, and the stimulation of dendritic cell maturation. A recent study indicated that DR3 may be a new receptor for E-selectin, which has been reported to be associated with cancer metastasis. DcR3 is a soluble receptor, highly expressed in various tumours, which lacks an apparent transmembrane segment, prevents cytokine response through ligand binding and neutralization, and is an inhibitor of apoptosis. DcR3 serves as a decoy receptor for FasL, LIGHT and VEGI. The cytokine LIGHT activates various anti-tumour functions and is expected to be a promising candidate for cancer therapy. Certain tumours may escape FasL-dependent immune-cytotoxic attack by expressing DcR3, which blocks FasL function. DR3/DcR3 play profound roles in regulating cell death and proliferation in cancer. The present review briefly discusses DR3/DcR3 and attempts to elucidate the role of these negative and positive players in cancer.

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

The principal Epstein-Barr virus (EBV) oncoprotein, latent membrane protein 1 (LMP1), has been suggested to contribute to the highly invasive nature of nasopharyngeal carcinoma (NPC). Signal transducer and activator of transcription 3 (STAT3) is a master transcriptional regulator in proliferation and apoptosis and is newly implicated in angiogenesis and invasiveness, which, in turn, are likely to contribute to the highly invasive character of NPC. The fundamental molecular mechanisms of LMP1-regulated STAT3 activation in NPC cell invasion have not been completely explored. Here, we showed that LMP1 signals the Janus kinase 3 (JAK3) and extracellular signal-regulated kinase 1/2 (ERK1/2) pathways upon the activation of STAT3 as well as STAT transactivation activity. LMP1 induces vascular endothelial growth factor (VEGF) expression via the JAK/STAT and mitogen-activated protein kinase (MAPK)/ERK signalling pathways. Induction of STAT3 by the human viral oncoprotein LMP1 may contribute to the invasion of NPC.

K252a induces anoikis-sensitization with suppression of cellular migration in Epstein-Barr virus (EBV)--associated nasopharyngeal carcinoma cells

Recent studies revealed an unexpected role of the neurotrophin receptor pathway, BDNF/TrkB signaling, in cancer metastasis and anoikis (i.e. detachment-induced cell death). Survival of cancer cells in detached state (known as anoikis-resistance) is known to be pre-requisite for metastasis. Nasopharyngeal carcinoma (NPC), an endemic head and neck cancer in Southeast Asia, is highly invasive, metastatic, and etiologically associated with Epstein-Barr virus (EBV, an oncovirus) infection. Mechanistic studies on the invasive/metastatic nature of NPC can facilitate the development of anti-metastatic therapy in NPC. Thus far, the role of BDNF/TrkB signaling in virus-associated human cancer is unclear. Here, using multiple cell line models of NPC with EBV-association (HONE-1-EBV, HK1-LMP1 and C666-1), we investigated the potential involvement of BDNF/TrkB signaling in cellular migration and anoikis-resistant characteristics of NPC. We found that all three EBV-associated NPC cell lines tested were intrinsically anoikis-resistant (i.e. survived in detached state) and expressed both BDNF and TrkB. BDNF stimulation induced cellular migration, but not proliferation of these cells. Further, we examined if pharmacologic targeting of anoikis-resistance of NPC cells can be achievable by a proof-of-concept Trk inhibitor, K252a, in these EBV-associated NPC models. Our results demonstrated that K252a, was able to attenuate BDNF-induced migration and proliferation of NPC cells. More importantly, we demonstrated for the first time that K252a harbored potent anoikis-sensitization activity (i.e. sensitizing cancer cells to detachment-induced cell death) against EBV-associated human cancer cells, namely NPC cells. This proof-of-concept study demonstrated that K252a, a Trk inhibitor, can potentially be used as an anoikis-sensitizing agent in NPC.

Epstein-Barr virus latent membrane protein 1 induces the chemotherapeutic target, thymidine phosphorylase, via NF-kappaB and p38 MAPK pathways

High thymidine phosphorylase (TP) expression is significantly correlated with poor prognosis in patients with nasopharyngeal carcinoma (NPC). NPC is an Epstein-Barr Virus (EBV)-associated cancer in which the EBV-encoded oncogene product, latent membrane protein 1 (LMP1), is expressed in approximately 60% of tumor tissues. However, no previous study has examined whether LMP1 is involved in up-regulating TP expression in NPC tissues. We herein show that LMP1 expression is correlated with TP expression in tumor cells, as examined by quantitative RT-PCR and immunohistochemical staining. We further show that the CTAR1 and CTAR2 domains of LMP1 mediate TP induction, as demonstrated by quantitative RT-PCR and Western blot analyses using LMP1 deletion and site-specific mutants. Mechanistically, LMP1-mediated TP induction is abolished by inhibitors of NF-kappaB and p38 MAPK, dominant-negative IkappaB and p38, and siRNA-mediated knockdown of p38 MAPK. Clinically, there were significant correlations among the expression levels of TP, activated p65, and phospho-p38 MAPK in NPC biopsy samples. Functionally, LMP1-mediated induction of TP expression enhanced the sensitivity of NPC cells to the chemotherapeutic prodrug, 5'-DFUR. Our results provide new insights into the roles of LMP1-mediated NF-kappaB and p38 MAPK signaling pathways in TP induction, potentially suggesting new therapeutic strategies for the treatment of NPC.