Endogenous decoy receptor 3 blocks the growth inhibition signals mediated by Fas ligand in human pancreatic adenocarcinoma

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.

The Role of Decoy Receptor DcR3 in Gastrointestinal Malignancy

Malignancies are among the leading causes of mortality worldwide. Early detection and treatment are the primary targets of clinical and translational research, and may be facilitated by the recognition of novel diagnostic and prognostic biomarkers. Decoy receptor 3 (DcR3) is a soluble receptor of the tumor necrosis factor receptor superfamily of proteins (TNFRSF), which associates with its respective TNF-like ligands, Fas-L, LIGHT, and TL1A. DcR3 has been recognised as a significant anti-apoptotic factor with prominent involvement in various inflammatory and neoplastic conditions. Increased intratumor expression of DcR3 and elevated soluble DcR3 protein content in the sera of patients has been reported for various malignancies. Recent published work has suggested that monitoring of local and systemic DcR3 may provide an attractive biomarker, mainly for defining subgroups of patients with aggressive tumor behaviour and poor prognosis. The aim of the present review is to summarize and critically present existing evidence regarding the potential clinical importance of monitoring DcR3 expression in patients with malignancies of the gastrointestinal tract, as well as liver and pancreatic cancer. We also present a detailed description of the pathophysiological basis that may underlie the involvement of DcR3 in gastrointestinal carcinogenesis. Based on these data, we comment on the potential applicability of DcR3 monitoring in the diagnosis and, most importantly, the prognostic stratification of patients.

Soluble CD95L in cancers and chronic inflammatory disorders, a new therapeutic target?

Although CD95L (also known as FasL) is still predominantly considered as a death ligand that induces apoptosis in infected and transformed cells, substantial evidence indicate that it can also trigger non-apoptotic signaling pathways whose pathophysiological roles remain to be fully elucidated. The transmembrane ligand CD95L belongs to the tumor necrosis factor (TNF) superfamily. After cleavage by metalloprotease, its soluble form (s-CD95L) fails to trigger the apoptotic program but instead induces signaling pathways promoting the aggressiveness of certain inflammatory disorders such as autoimmune diseases and cancers. We propose to evaluate the various pathologies in which the metalloprotease-cleaved CD95L is accumulated and analyze whether this soluble ligand may play a significant role in the pathology progression. Based on the TNFα-targeting therapeutics, we envision that targeting the soluble form of CD95L may represent a very attractive therapeutic option in the pathologies depicted herein.

Expression profiling of genes in rheumatoid fibroblast-like synoviocytes regulated by Fas ligand via cDNA microarray analysis

Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation in synovial tissues. Hyperplasia of synovial tissues leads to the formation of pannus that invades the joint cartilage and bone, resulting in joint destruction. Fas ligand (FasL), which is a member of the tumor necrosis factor superfamily, contributes to the pathogenesis of autoimmune diseases, including RA. The current study attempted to identify genes whose expressions in rheumatoid fibroblast-like synoviocytes (RA-FLS) were regulated by FasL, using cDNA microarray. A total of four individual lines of primary cultured RA-FLS were incubated either with recombinant human FasL protein or PBS as an unstimulated control for 12 h. Gene expression was detected using a microarray assay. The results revealed the expression profiles of genes in RA-FLS regulated by Fas and investigated the functions of the genes that were regulated. Among the genes in this profile, the mRNA expression changes of the following genes were indicated to be of note using RT-qPCR: Dual specificity phosphatase 6, epiregulin, interleukin 11, angiopoietin-like 7, protein inhibitor of activated STAT 2 and growth differentiation factor 5. These genes may affect the pathogenesis of RA by affecting apoptosis, proliferation, cytokine production, cytokine-induced inflammation, intracellular signaling, angiogenesis, bone destruction and chondrogenesis. To the best of our knowledge, the current study is the first study to reveal the expression profile of genes in RA-FLS regulated by FasL. The data demonstrated that FasL may regulate the expression of a number of key molecules in RA-FLS, thus affecting RA pathogenesis. Further studies of the genes detected may improve the understanding of RA pathogenesis and provide novel treatment targets for RA.

The Paradoxical Web of Pancreatic Cancer Tumor Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is increasing in incidence and is projected to become the second leading cause of cancer death in the United States. Despite significant advances in understanding the disease, there has been minimal increase in PDAC patient survival. PDAC tumors are unique in the fact that there is significant desmoplasia. This generates a large stromal compartment composed of immune cells, inflammatory cells, growth factors, extracellular matrix, and fibroblasts, comprising the tumor microenvironment (TME), which may represent anywhere from 15% to 85% of the tumor. It has become evident that the TME, including both the stroma and extracellular component, plays an important role in tumor progression and chemoresistance of PDAC. This review will discuss the multiple components of the TME, their specific impact on tumorigenesis, and the multiple therapeutic targets.

Expression profiling of genes in rheumatoid fibroblast-like synoviocytes regulated by tumor necrosis factor-like ligand 1A using cDNA microarray analysis

Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation in synovial tissues. Hyperplasia of synovial tissue leads to the formation of pannus, which invades joint cartilage and bone resulting in joint destruction. Tumor necrosis factor-like ligand 1A (TL1A), a member of the tumor necrosis factor superfamily (TNFSF15), contributes to the pathogenesis of autoimmune diseases, including RA. In the present study, a cDNA microarray was used to search for genes whose expression in rheumatoid fibroblast-like synoviocytes (RA-FLS) were regulated by TL1A. Four individual lines of primary cultured RA-FLS were incubated either with recombinant human TL1A protein or phosphate-buffered saline, as an unstimulated control, for 12 h. Gene expression was then detected through the microarray assay. The results revealed the expression profiles of genes in RA-FLS regulated by TL1A. The present study also demonstrated the functions of those genes whose expression in RA-FLS was regulated by TL1A. Among the genes in this profile, the present study focused on the following genes: Spectrin repeat-containing nuclear envelope 1, Fc receptor-like 2, PYD (pyrin domain)-containing 1, cell division cycle 45 homolog, signal transducer and activator of transcription 5B, and interferon regulatory factor 4. These genes may affect the pathogenesis of RA, including proliferation, regulation of B cells and T cells, inflammation, and cytokine processing. The present study revealed for the first time, to the best of our knowledge, the expression profile of genes in RA-FLS regulated by TL1A. The data indicate that TL1A may regulate the gene expression of various key molecules in RA-FLS, thus affecting the pathogenesis of RA. Further investigations of the genes detected in the current profiles may provide a deeper understanding of the pathogenesis and a novel target for the treatment of RA.

Anti-oral cancer effects of triptolide by downregulation of DcR3 in vitro, in vivo, and in preclinical patient-derived tumor xenograft model

Background

Aberrant expression of decoy receptor 3 (DcR3) is considered to be a diagnostic and therapeutic target for human cancers. The aim of this study was to assess DcR3 as a target of the anticancer effects of triptolide (TPL) in preclinical patient‐derived tumor xenograft (PDTX) models of oral squamous cell carcinoma (OSCC).

Methods

The expression of DcR3 was evaluated through immunohistochemistry, and correlations were examined using clinical variables. The effects of TPL on the expression of DcR3 and cell proliferation were investigated in OSCC cell lines and in PDTX models.

Results

DcR3 overexpression was associated with overall survival and tumor size. TPL significantly decreased tumor growth. Moreover, TPL inhibited the expression of metastasis‐associated protein 1 (MTA1), a transcription factor for DcR3 in vivo, in vitro, and in PDTX models.

Conclusion

TPL appeared to exert anticancer effects by repressing DcR3 and MTA1 in vitro, in vivo, and in PDTX models.

Anti-apoptosis Effect of Decoy Receptor 3 in Cholangiocarcinoma Cell Line TFK-1

Background:

Decoy receptor 3 (DcR3) is a protein with anti-apoptotic effect that belongs to the tumor necrosis factor receptor superfamily. DcR3 is highly expressed in a variety of malignant tumors including cholangiocarcinoma and its expression was found to be related to the clinical stage, the invasion, and the metastasis of the tumor. This in vitro study aimed to investigate the effect of downregulated expression of DcR3 on cell viability, cell apoptosis, and cell cycle in cholangiocarcinoma cell line TFK-1.

Methods:

Three different cell lines were cultured: human cholangiocarcinoma TFK-1, human biliary epithelial carcinoma HuCCT-1, and human cholangiocarcinoma RBE. The cholangiocarcinoma cell line with the highest expression of DcR3 was selected for further investigation. The expression of DcR3 was silenced/knocked down by transfection with DcR3-siRNA in the selected cell line. Various biological phenotype parameters such as cell viability, apoptosis, and cell cycle were observed.

Results:

The mRNA and protein levels of DcR3 were measured in the three cell lines, and TFK-1 was selected. After the treatment with DcR3-siRNA for 48 h, DcR3 mRNA and protein expression in the treatment group were 38.45% (P < 0.01) and 48.03% (P < 0.05) of that of the control, respectively. It was found that the cell viability decreased to 61.87% of the control group (P < 0.01) after the downregulation of DcR3 in cholangiocarcinoma cell line TFK-1 by transfection with DcR3-siRNA, while the percentage of apoptotic cells was 2.98 times as compared with the control group (P < 0.05). Compared with the control group the ratio of G₀/G₁ increased, and the ratio of G₂/M decreased in the treatment group. However, the differences were not statistically significant.

Conclusions:

The effect of DcR3 on the growth and apoptosis of cholangiocarcinoma has been demonstrated. DcR3 is not only a predictive marker for malignant tumor but it is also likely to be a potential target for cancer gene therapy. Further studies should focus on exploring the binding ligand of DcR3, the signaling pathway involved, and the molecular mechanism for the regulation of DcR3 expression in cholangiocarcinoma.

Decoy receptor 3 down-regulates centrosomal protein 70 kDa specifically in rheumatoid synovial fibroblasts

OBJECTIVES

Decoy receptor 3 (DcR3) competitively binds to Fas ligand, lymphotoxin-related inducible ligand that competes for glycoprotein D binding to herpes virus entry mediator on T cells (LIGHT) and TNF-like ligand 1A (TL1A), thereby preventing their effects. Using a microarray assay, we previously newly identified centrosomal protein 70 kDa (CEP70) as one of the genes whose expression in fibroblast-like synoviocytes from patients with rheumatoid arthritis (RA-FLS) is reduced by DcR3. Here, we investigated the significance of DcR3 regulation of CEP70 for RA-FLS.

METHODS

Synovial samples were obtained from RA patients who had never been treated with biologics and from osteoarthritis (OA) patients. CEP70 mRNA expression was quantified using RT-qPCR analysis. CEP70 protein expression was assessed using immunohistochemical and western blot analyses.

RESULTS

CEP70 was expressed predominantly in the superficial lining layer in RA synovial tissue. CEP70 expression was dose-dependently downregulated by DcR3-Fc in RA-FLS but was not downregulated in OA-FLS. TL1A antibody prevented the DcR3-Fc inhibitory effects on CEP70 expression in RA-FLS.

CONCLUSIONS

These results indicated that DcR3 reduces CEP70 expression in RA-FLS by binding to membrane-bound TL1A and may suppress RA-FLS proliferation. The reduction in CEP70 expression by DcR3/TL1A signaling may control the hyperplasia of RA synovium.

Downregulation of DcR3 sensitizes hepatocellular carcinoma cells to TRAIL-induced apoptosis

Decoy receptor 3 (DcR3) has been recently described as an antiapoptosis and prometastasis factor since it can competitively bind to FasL, TL1A, and LIGHT, and it is highly expressed in many malignant tumors. Downregulation of DcR3 can promote tumor cell apoptosis and inhibit metastasis. A previous study demonstrated that reduction of DcR3 could induce tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis in pancreatic cancer cells. However, whether such an effect is seen in hepatocellular carcinoma (HCC) remains to be explored. This study was designed to investigate the sensitivity of HCC cells to TRAIL after silencing DcR3, and this was done by evaluating the expression of DcR3 in HCC cells and the effect on TRAIL-mediated apoptosis after downregulation of DcR3. Our data showed that DcR3 was highly expressed in HepG2, BEL-7402, Hep3B, Huh-7, MHCC97H, and SMCC7721 cell lines compared with normal liver cell line LO-2. Both HepG2 and BEL-7402 were tolerant to TRAIL-mediated apoptosis, and the tolerance was negatively correlated to the expression of DcR3. Silencing of DcR3 with shRNA and treatment with TRAIL induced obvious apoptosis in HepG2 and BEL-7402, with more cancer cells found in the G1 phase. SiDcR3 combined with TRAIL could induce activation of caspases-3, -8, and -9, raise the expression of the apoptotic protein Bax, and reduce the expression of antiapoptotic proteins (Bcl-2, Mcl-1, Bcl-XL, IAP-2, and survivin). Caspase-8 inhibitor Ac-IETD-CHO significantly decreased the activation of caspase cascade, indicating that the extrinsic pathway may have a vital role in the apoptotic events induced by SiDcR3/TRAIL. Furthermore, our results showed that the TRAIL death receptor 5 (DR5) was upregulated and that DR5 neutralizing antibody abrogated the effect of SiDcR3. Our results demonstrated that downregulation of DcR3 could enhance TRAIL-mediated apoptosis in HCC through the death receptor pathway. In the future, this might be useful as a clinical treatment method of liver cancer.

Role of immune cells in pancreatic cancer from bench to clinical application: An updated review

BACKGROUND

Pancreatic cancer (PC) remains difficult to treat, despite the recent advances in various anticancer therapies. Immuno-inflammatory response is considered to be a major risk factor for the development of PC in addition to a combination of genetic background and environmental factors. Although patients with PC exhibit evidence of systemic immune dysfunction, the PC microenvironment is replete with immune cells.

METHODS

We searched PubMed for all relevant English language articles published up to March 2016. They included clinical trials, experimental studies, observational studies, and reviews. Trials enrolled at Clinical trial.gov were also searched.

RESULTS

PC induces an immunosuppressive microenvironment, and intratumoral activation of immunity in PC is attenuated by inhibitory signals that limit immune effector function. Multiple types of immune responses can promote an immunosuppressive microenvironment; key regulators of the host tumor immune response are dendritic cells, natural killer cells, macrophages, myeloid derived suppressor cells, and T cells. The function of these immune cells in PC is also influenced by chemotherapeutic agents and the components in tumor microenvironment such as pancreatic stellate cells. Immunotherapy of PC employs monoclonal antibodies/effector cells generated in vitro or vaccination to stimulate antitumor response. Immune therapy in PC has failed to improve overall survival; however, combination therapies comprising immune checkpoint inhibitors and vaccines have been attempted to increase the response.

CONCLUSION

A number of studies have begun to elucidate the roles of immune cell subtypes and their capacity to function or dysfunction in the tumor microenvironment of PC. It will not be long before immune therapy for PC becomes a clinical reality.

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.

Interleukin‑12B is upregulated by decoy receptor 3 in rheumatoid synovial fibroblasts

Decoy receptor 3 (DcR3) competitively binds to three ligands, Fas ligand, lymphotoxin‑related inducible ligand that competes for glycoprotein D binding to herpesvirus entry mediator on T cells and tumor necrosis factor‑like ligand 1A (TL1A), to prevent their effects. Recent studies have suggested that DcR3 directly affects cells as a ligand. Using a microarray assay, our group newly identified interleukin (IL)‑12B, which encodes the p40 subunit common to IL‑12 and IL‑23, as one of the genes for which expression in fibroblast‑like synoviocytes from patients with rheumatoid arthritis (RA‑FLS) is induced by DcR3. The present study demonstrated that IL‑12B mRNA expression was upregulated by DcR3‑Fc in RA‑FLS in a dose‑dependent manner, but not in OA‑FLS. IL‑12B p40 protein in RA‑FLS was increased when stimulated with DcR3‑Fc. Pre‑treatment with anti‑TL1A antibody suppressed the upregulation of IL‑12B mRNA in RA‑FLS stimulated with DcR3‑Fc. DcR3 mRNA expression in RA‑FLS was induced by IL‑23, but not by IL‑12. These results indicated that DcR3 may increase IL‑12 or IL‑23 by inducing IL‑12B p40 expression via membrane‑bound TL1A on RA‑FLS and that IL‑23 reciprocally induces DcR3 expression in RA‑FLS. DcR3 and IL‑23 may interact in a feedback loop that aggravates local inflammation in patients with RA.

Expression of tumor necrosis factor-α-induced protein 8 in stage III gastric cancer and the correlation with DcR3 and ERK1/2

Tumor necrosis factor (TNF)-α-induced protein 8 (TIPE) is a recently identified protein that is considered to be associated with various malignancies, including esophageal, breast and pancreatic cancer; however, the importance of TIPE in gastric cancer (GC) remains unknown. Decoy receptor 3 (DcR3) is a member of the tumor necrosis factor receptor superfamily that is expressed in digestive system neoplasms. The expression of DcR3 is regulated by the mitogen-activated protein kinase (MAPK)/MAPK kinase/extracellular signal-regulated kinase (ERK) signaling pathway. Reverse transcription-polymerase chain reaction was performed to detect the expression of TIPE, ERK and DcR3 in the pathological and tumor-adjacent normal gastric tissues of 30 patients that demonstrated stage III gastric adenocarcinoma. The expression and distribution of the TIPE protein was examined using immunohistochemistry, and the clinical significance and expression levels of DcR3 and ERK1/2 were evaluated. The expression of TIPE, ERK1/2 and DcR3 in the tumor tissues of GC was significantly increased compared with paracarcinoma tissues (P<0.05). In addition, TIPE expression positively correlated with DcR3 and ERK1 levels (r=0.538 and r=0.462, respectively; P<0.05). There was no statistical difference between tumor tissues from patients with varying age, gender, differentiation or lymph node metastasis (P>0.05). TIPE may be vital in the progression of GC. TIPE may be associated with the expression of DcR3 and ERK1/2, which may be involved in the cell apoptosis of GC. The present study elucidates the potential function of TIPE as a novel marker and therapeutic target for GC.

Reduced expression of caspase-8 and cleaved caspase-3 in pancreatic ductal adenocarcinoma cells

Pancreatic ductal adenocarcinoma (PDAC) is a rare neoplasm that affects the gastrointestinal system, and is characterized by a high mortality rate. It has been demonstrated that apoptosis has a significant role in the regulation of cancer cells. Therefore, the aim of the present study was to immunohistochemically assess the expression of proteins belonging to the caspase family, namely caspase-8, pro-caspase-3 and cleaved (active) caspase-3 in pancreatic cancer. The study group consisted of 29 patients exhibiting PDAC. Protein expression was evaluated by immunohistochemical methods. The expression of caspase-8 in normal cells was negative in 17.2% of cases and positive in 82.8% of cases. All cases demonstrated pro-caspase-3 expression in normal pancreatic cells, compared with 93.1% of cancer cells. Staining for activated caspase-3 was positive in 27 normal tissue cases, compared with positivity in only 10 cancer cases. Caspase-8 expression positively correlated with cleaved caspase-3 expression in the cytoplasm of cancer cells (P<0.002). Caspase-3 expression was identified to correlate with inflammatory peritumoral infiltration (P<0.015). No correlation was observed between caspase expression and any other clinicopathological parameters. The results of the present study demonstrated aberrant initiation of cancer cell apoptosis in PDAC via a decrease in caspase-8 expression, which may lead to disorders in the activation of effector caspase-3.

Decoy receptor 3 regulates the expression of tryptophan hydroxylase 1 in rheumatoid synovial fibroblasts

Decoy receptor 3 (DcR3) is expressed in rheumatoid arthritis fibroblast‑like synoviocytes (RA‑FLS) and downregulates the expression of tryptophan hydroxylase 1 (TPH1), which is the rate‑limiting enzyme in serotonin synthesis. The aim of the present study was to determine the specificity of the effects of DcR3 on TPH1 in RA‑FLS, and therefore determine whether DcR3 had the potential to modulate the pathogenesis of RA. The present study also aimed to compare the effects of DcR3 and inflammatory cytokines on the expression of TPH1 in RA‑FLS and osteoarthritis (OA)‑FLS. Primary cultured RA‑ or OA‑FLS were incubated with 1.0 µg/ml DcR3‑Fc protein or 1.0 µg/ml control immunoglobulin G (IgG)1 for 12 h, or with 1.0 ng/ml tumor necrosis factor (TNF)α, 1.0 ng/ml interleukin (IL)‑1β or serum‑free Opti‑MEM only, for 24 h. The relative mRNA expression levels of TPH1 were subsequently quantified using reverse transcription‑polymerase chain reaction. The expression of serotonin in RA or OA synovial tissue was detected using immunohistochemistry. The mRNA expression of TPH1 was observed in both RA‑ and OA‑FLS and was significantly decreased following treatment with DcR3 in the RA‑FLS, however, not in the OA‑FLS. The mRNA expression of TPH1 was significantly decreased following treatment with TNFα or IL‑1β in both the RA‑ and OA‑FLS. The expression of serotonin in the multi‑layered lining synovial cells of RA and the outer layer lining synovial cells of OA was detected using immunohistochemistry. The present study is the first, to the best of our knowledge, to demonstrate that the expression of TPH1 in FLS is downregulated by inflammatory cytokines, and that DcR3 suppressed the expression of TPH1 in RA‑FLS in a disease‑specific manner. These results suggested that synovial serotonin may be involved in the pathogenesis of RA, and that TPH1 and DcR3 may be potential therapeutic targets for the treatment of RA.

Decoy receptor 3 suppresses FasL-induced apoptosis via ERK1/2 activation in pancreatic cancer cells

Resistance to Fas Ligand (FasL) mediated apoptosis plays an important role in tumorigenesis. Decoy receptor 3 (DcR3) is reported to interact with FasL and is overexpressed in some malignant tumors. We sought to investigate the role of DcR3 in resistance to FasL in pancreatic cancer. We compared expression of apoptosis related genes between FasL-resistant SW1990 and FasL-sensitive Patu8988 pancreatic cell lines by microarray analysis. We explored the impact of siRNA knockdown of, or exogenous supplementation with, DcR3 on FasL-induced cell growth inhibition in pancreatic cancer cell lines and expression of proteins involved in apoptotic signaling. We assessed the level of DcR3 protein and ERK1/2 phosphorylation in tumor and non-tumor tissue samples of 66 patients with pancreatic carcinoma. RNAi knockdown of DcR3 expression in SW1990 cells reduced resistance to FasL-induced apoptosis, and supplementation of Patu8988 with rDcR3 had the opposite effect. RNAi knockdown of DcR3 in SW1990 cells elevated expression of caspase 3, 8 and 9, and reduced ERK1/2 phosphorylation (P < 0.05), but did not alter phosphorylated-Akt expression. 47 tumor tissue specimens, but only 15 matched non-tumor specimens stained for DcR3 (χ(2) = 31.1447, P < 0.001). The proliferation index of DcR3 positive specimens (14.26  ±  2.67%) was significantly higher than that of DcR3 negative specimens (43.58  ±  7.88%, P < 0.01). DcR3 expression positively correlated with p-ERK1/2 expression in pancreatic cancer tissues (r = 0.607, P < 0.001). DcR3 enhances ERK1/2 phosphorylation and opposes FasL signaling in pancreatic cancer cells.

Amplification of Genomic DNA for Decoy Receptor 3 Predicts Post-Resection Disease Recurrence in Breast Cancer Patients

Background

Decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor (TNFR) superfamily, shows inhibitory effects on Fas-mediated apoptosis. Currently, data are lacking on the correlation between DcR3 and the recurrence of breast cancer. The authors examined DcR3 mRNA expression and genomic amplification in breast cancer, and investigated the effect of DcR3 gene amplification on prognosis of patients.

Methods

A total of 95 patients formed the basis of the current retrospective study. DcR3 mRNA expression in breast cancer tissues was examined by RNase protection assay and in situ hybridization. DcR3 gene amplification was examined by quantitative polymerase chain reaction. The correlation between DcR3 gene amplification status and clinicopathological factors was examined and also the relationship between DcR3-Amp and relapse and survival.

Results

The relative copy numbers of DcR3 genomic DNA correlated significantly with the levels of DcR3 mRNA expression (ρ = 0.755, P = 0.0067). In addition, lymphatic invasion correlated significantly with DcR3 gene amplification (P = 0.012). However, there was no correlation between the remaining clinicopathological factors and DcR3 gene amplification. In the univariate analysis, the recurrence-free survival (RFS) rate of patients who were positive for DcR3 gene amplification was significantly lower than that of patients who were negative for DcR3 gene amplification (P = 0.0271). Multivariate analysis showed that DcR3 gene amplification (P = 0.028) and disease stage (P < 0.001) remained significant independent predictors of RFS.

Conclusions

DcR3 gene amplification was significantly correlated with lymphatic invasion, and also DcR3 gene amplification predicts recurrence after resection, which may be an important prognostic factor in breast cancer patients.

Reduction of decoy receptor 3 enhances TRAIL-mediated apoptosis in pancreatic cancer

Most human pancreatic cancer cells are resistant to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. However, the mechanisms by which pancreatic cancer cells utilize their extracellular molecules to counteract the proapoptotic signaling mediated by the TNF family are largely unknown. In this study, we demonstrate for the first time that DcR3, a secreted decoy receptor that malignant pancreatic cancer cells express at a high level, acts as an extracellular antiapoptotic molecule by binding to TRAIL and counteracting its death-promoting function. The reduction of DcR3 with siRNA unmasked TRAIL and greatly enhanced TRAIL-induced apoptosis. Gemcitabine, a first-line drug for pancreatic cancer, also reduced the level of DcR3. The addition of DcR3 siRNA further enhanced gemcitabine-induced apoptosis. Notably, our in vivo study demonstrated that the therapeutic effect of gemcitabine could be enhanced via further reduction of DcR3, suggesting that downregulation of DcR3 in tumor cells could tip the balance of pancreatic cells towards apoptosis and potentially serve as a new strategy for pancreatic cancer therapy.

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.

DcR3 regulates the growth and metastatic potential of SW480 colon cancer cells

Decoy receptor 3 (DcR3) is considered to have anti‑apoptotic and pro-metastatic functions, suggesting it might be a therapeutic target. We examined the role and mechanisms of DcR3 on growth and the metastatic ability of SW480 colon cancer cells to provide therapeutic information for targeting DcR3 by RNA interference (RNAi) technology. Growth and the metastatic ability were inhibited, apoptosis was induced and cell cycle profile was changed after decreasing DcR3 expression, with lower levels of vascular endothelial growth factors (VEGFs) and matrix metalloproteinases (MMPs) expression. Our results implied the therapeutic potential of silencing DcR3 expression by RNAi in colon cancer.

Silencing of decoy receptor 3 (DcR3) expression by siRNA in pancreatic carcinoma cells induces Fas ligand-mediated apoptosis in vitro and in vivo

Decoy receptor 3 (DcR3) is abundantly expressed in human tumors and protects cells from a wide range of apoptotic stimuli. In this study, we demonstrate that DcR3 is overexpressed in pancreatic carcinoma cells, and that the pancreatic carcinoma cell lines, Panc-1 and SW1990, are resistant to Fas ligand (FasL)-mediated apoptosis. To further define the function of DcR3 in cell growth and apoptosis, we used small interfering RNA (siRNA) to knockdown the expression of the DcR3 gene in Panc-1 and SW1990 cells. Our results revealed that the silencing of DcR3 expression enhanced the inhibitory effects of FasL and reduced the capabiltiy of the cells for proliferation and colony formation in vitro. In addition, the downregulation of DcR3 modulated the cell apoptotic regulators, Fas-associated death domain (FADD), caspase‑3 and caspase‑8, thus triggering cell apoptosis. Furthermore, the knockdown of DcR3 inhibited the growth of Panc-1 tumor xenografts. Taken together, our findings indicate that DcR3 is important in cancer progression and may be a used as a potential therapeutic target for the gene therapy of pancreatic carcinoma.

'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.

The serologic decoy receptor 3 (DcR3) levels are associated with slower disease progression in HIV-1/AIDS patients

BACKGROUND/PURPOSE

The decoy receptor 3 (DcR3) is a member of the tumor necrosis factor receptor (TNFR) super-family. It counteracts the biological effects of Fas ligands and inhibits apoptosis. The goals of this study were to understand the associations between serologic DcR3 (sDcR3) levels and different human immunodeficiency virus type 1 (HIV-1) subtypes, as well as the AIDS disease progression.

METHODS

Serum samples from 61 HIV/AIDS patients, who had been followed up every 6 months for 3 years, were collected. sDcR3 levels were quantified using an enzyme immunoassay (EIA).

RESULTS

The sDcR3 levels in patients with HIV-1 subtype B were significantly higher than those in patients infected with subtype CRF01_AE (p < 0.001). In addition, multivariable linear mixed model analysis demonstrated that HIV-1 subtype B and slow disease progression were associated with higher levels of sDcR3, adjusting for potential predictors (p = 0.0008 and 0.0455, respectively).

CONCLUSION

HIV-1-infected cells may gain a survival advantage by activating DcR3, which prevents infected cell detection by the host immune system. These data indicate that the sDcR3 level is a biomarker for AIDS disease progression.

Isolation and characterization of LIGHT (TNFSF14) gene homologue in zebrafish (Danio rerio)

The tumor necrosis factor superfamily (TNFSF) proteins are cytokines involved in many biological processes. In this study, the TNF superfamily member 14 (TNFSF14, LIGHT) has been isolated from zebrafish Danio rerio (designated zLIGHT). The full-length open reading frame (ORF) of zLIGHT cDNA consists of 708 bp encoding a protein of 235 amino acids. The zLIGHT open reading frame (ORF) genomic sequence consists of three introns and four exons, is about 9.9 kb in size. Real-time quantitative PCR (qPCR) analysis suggested that zLIGHT was predominantly expressed in zebrafish spleen. The soluble LIGHT (zsLIGHT) had been cloned into the pSUMO vector, SDS-PAGE and Western blotting analysis confirmed that the recombinant protein SUMO-zsLIGHT was efficiently expressed in Escherichia coli BL21 (DE3). Laser scanning confocal microscopy analysis showed that SUMO-zsLIGHT could bind to its receptors on T cells. LIGHT is involved in many important biological effects, including up-regulating proinflammatory chemokines, cytokines, inducing cell death, apoptosis, and enhancing T cell survival. Zebrafish may conduct as a model animal for further research on LIGHT.

Significance of decoy receptor 3 (Dcr3) and external-signal regulated kinase 1/2 (Erk1/2) in gastric cancer

Background

Decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor (TNFR) superfamily, is associated with anti-tumor immunity suppression. It is highly expressed in many tumors, and its expression can be regulated by the MAPK/MEK/ERK signaling pathway. The MAPK/MEK/ERK pathway has been reported to be a regulator in tumor occurrence, development and clonal expansion. External-signal regulated kinase (ERK) is a vital member of this pathway.

Results

The expression of DcR3 and ERK1/2 in tumor tissues of gastric cancer patients was significantly higher than the non-cancerous group (P < 0.05). There was no statistical difference among tumor tissues from patients with different ages or gender, and even of different differentiation (P > 0.05). However, in patients with stage I gastric cancer, the DcR3 and ERK1/2 levels were significantly lower than patients with more advanced stages.

Conclusions

DcR3 and ERK1/2 play a vital role in the development of gastric cancer, and they may be new markers for indicating the efficiency of gastric cancer treatment in the future.

Triptolide triggers the apoptosis of pancreatic cancer cells via the downregulation of Decoy receptor 3 expression

PURPOSE

Triptolide (TPL) is a diterpenoid triepoxide that effectively induces apoptosis in a wide variety of cancer cells. However, the detailed mechanism by which TPL activates caspase cascade remains elusive. This study aimed to examine the antitumor effects of TPL against pancreatic cancer and investigate the underlying mechanism.

METHODS

Cell proliferation was evaluated by sulforhodamine B assay. The apoptosis was evaluated by caspase activity assay, Western blot and flow cytometry. DcR3 level was measured by ELISA. AsPC-1 xenografts were established to compare the in vivo antitumor effects of TPL and Gemcitabine.

RESULTS

TPL inhibited the proliferation and induced the apoptosis of pancreatic cancer cells in a dose- and time-dependent manner. TPL also inhibited DcR3 expression in a dose- and time-dependent manner. siRNA-mediated DcR3 knockdown sensitized pancreatic cancer cells to TPL-induced apoptosis. In vivo, DcR3 siRNA significantly enhanced TPL-induced apoptosis and tumor growth inhibition. Moreover, TPL showed less toxicity compared to Gemcitabine in mice model.

CONCLUSIONS

TPL induces the apoptosis of pancreatic cancer cells via the downregulation of DcR3 expression and has the potential as an effective agent against pancreatic cancer.

Decoy receptor 3 enhances tumor progression via induction of tumor-associated macrophages

Tumor-associated macrophages (TAMs) are the major component of tumor-infiltrating leukocytes. TAMs are heterogeneous, with distinct phenotypes influenced by the microenvironment surrounding tumor tissues. Decoy receptor 3 (DcR3), a member of the TNFR superfamily, is overexpressed in tumor cells and is capable of modulating host immunity as either a neutralizing decoy receptor or an effector molecule. Upregulation of DcR3 has been observed to correlate with a poor prognosis in various cancers. However, the mechanisms underlying the DcR3-mediated tumor-promoting effect remain unclear. We previously demonstrated that DcR3 modulates macrophage activation toward an M2-like phenotype in vitro and that DcR3 downregulates MHC class II expression in TAMs via epigenetic control. To investigate whether DcR3 promotes tumor growth, CT26-DcR3 stable transfectants were established. Compared with the vector control clone, DcR3-transfectants grew faster and resulted in TAM infiltration. We further generated CD68 promoter-driven DcR3 transgenic (Tg) mice to investigate tumor growth in vivo. Compared with wild-type mice, macrophages isolated from DcR3-Tg mice displayed higher levels of IL-10, IL-1ra, Ym1, and arginase activity, whereas the expression of IL-12, TNF-α, IL-6, NO, and MHC class II was downregulated. Significantly enhanced tumor growth and spreading were observed in DcR3-Tg mice, and the enhanced tumor growth was abolished by arginase inhibitor N-ω-hydroxy-l-norarginine and histone deacetylase inhibitor sodium valproate. These results indicated that induction of TAMs is an important mechanism for DcR3-mediated tumor progression. Our findings also suggest that targeting DcR3 might help in the development of novel treatment strategies for tumors with high DcR3 expression.

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.

Examination of apoptosis signaling in pancreatic cancer by computational signal transduction analysis

Background

Pancreatic ductal adenocarcinoma (PDAC) remains an important cause of cancer death. Changes in apoptosis signaling in pancreatic cancer result in chemotherapy resistance and aggressive growth and metastasizing. The aim of this study was to characterize the apoptosis pathway in pancreatic cancer computationally by evaluation of experimental data from high-throughput technologies and public data bases. Therefore, gene expression analysis of microdissected pancreatic tumor tissue was implemented in a model of the apoptosis pathway obtained by computational protein interaction prediction.

Methodology/Principal Findings

Apoptosis pathway related genes were assembled from electronic databases. To assess expression of these genes we constructed a virtual subarray from a whole genome analysis from microdissected native tumor tissue. To obtain a model of the apoptosis pathway, interactions of members of the apoptosis pathway were analysed using public databases and computational prediction of protein interactions. Gene expression data were implemented in the apoptosis pathway model. 19 genes were found differentially expressed and 12 genes had an already known pathophysiological role in PDAC, such as Survivin/BIRC5, BNIP3 and TNF-R1. Furthermore we validated differential expression of IL1R2 and Livin/BIRC7 by RT-PCR and immunohistochemistry. Implementation of the gene expression data in the apoptosis pathway map suggested two higher level defects of the pathway at the level of cell death receptors and within the intrinsic signaling cascade consistent with references on apoptosis in PDAC. Protein interaction prediction further showed possible new interactions between the single pathway members, which demonstrate the complexity of the apoptosis pathway.

Conclusions/Significance

Our data shows that by computational evaluation of public accessible data an acceptable virtual image of the apoptosis pathway might be given. By this approach we could identify two higher level defects of the apoptosis pathway in PDAC. We could further for the first time identify IL1R2 as possible candidate gene in PDAC.

TNFRSF6B neutralization antibody inhibits proliferation and induces apoptosis in hepatocellular carcinoma cell

The tumor necrosis factor receptor super-family member 6b (TNFRSF6B) is over-expressed in various human cancers, but its function in hepatocellular carcinoma (HCC) remains uncertain. The aim of the study was to investigate the relationship between TNFRSF6B expression and apoptosis in HCC and the effect of anti-TNFRSF6B neutralization monoclonal antibody (McAb) on HCC cells. TNFRSF6B mRNA and protein expression were compared with apoptosis in 78 cases of HCC. Proliferation, cell cycle, apoptosis, and migration ability of liver cancer cells co-cultured with anti-TNFRSF6B McAb were also detected. TNFRSF6B mRNA and protein expression in the tumor tissues negatively correlated with apoptosis. Cell proliferation was decreased, cell cycle was arrested in G1/S-phase, apoptosis was increased, and migration ability was inhibited by anti-TNFRSF6B McAb in vitro. Anti-TNFRSF6B McAb could be useful to suppress proliferation and induce apoptosis in HCC. Thus, TNFRSF6B might be a critical, targeted therapy strategy for HCC.

Creation of a LIGHT mutant with the capacity to evade the decoy receptor for cancer therapy

The cytokine LIGHT activates various anti-tumor functions through its two receptors, lymphotoxin beta receptor (LTbetaR) and herpes virus entry mediator (HVEM), and is expected to be a promising candidate for cancer therapy. However, LIGHT is also trapped by decoy receptor 3 (DcR3), which is highly expressed in various tumors. Here, we used phage display technique to create LIGHT mutants that specifically bind LTbetaR and HVEM, and is not trapped by DcR3 for optimized cancer therapy. We constructed phage library displaying structural variants of LIGHT with randomized amino acid residues. After the affinity panning, we created 6 clones of LIGHT mutants as candidates for DcR3-evading LIGHT. Analysis of binding affinities showed that all candidates had 10-fold lower affinities for DcR3 than wild-type LIGHT, while 5 of the 6 clones had almost the same affinity for LTbetaR and HVEM. Furthermore, analysis of detailed binding kinetics showed that lower affinity for DcR3 is dependent on their faster off-rate. Further, we showed that the LIGHT mutant had almost the same cytotoxicity via LTbetaR, and had 62-fold higher DcR3-evading capacity compared to the wild type. Our data provide valuable information for construction of more functional LIGHT mutants that might be powerful tools for cancer therapy.

Escaping immune surveillance in cancer: is denbinobin the panacea?

The bane of anti-cancer therapy is usually the development of resistance to apoptosis in malignant cells. Identification of strategies to re-sensitize cancer cells to apoptosis has now become a top priority in anti-cancer research. Denbinobin is a novel, naturally occurring phenathroquinone isolated from orchids of the genus Dendrobium that has remarkable anti-cancer activities demonstrated both in vitro and in vivo. Recently denbinobin has been shown to diminish the levels of expression of the decoy receptor-3 and also to act synergistically with Fas ligand to induce apoptosis in a pancreatic adenocarcinoma cell line. There is hope that denbinobin could be developed as an adjuvant in combination therapies aimed at killing cancers that rely on decoy receptors to evade the host's immune surveillance.

Clinical significance of elevated serum DcR3 in patients with hepatocellular carcinoma

AIM: To investigate the diagnostic value and clinical significance of elevated serum decoy receptor 3 (DcR3) in patients with hepatocellular carcinoma (HCC).

METHODS: Serum DcR3 levels were measured using enzyme-linked immunosorbent assay (ELISA) in 67 patients with HCC, 8 patients with liver cirrhosis, 17 patients with cholecystitis and 28 healthy individuals. Serum alpha fetoprotein (AFP) levels were measured by chemiluminescence. The expression of DcR3 in HCC tissue was evaluated by immunohistochemistry (IHC).

RESULTS: The levels of serum DcR3 in both HCC and liver cirrhosis patients were significantly higher than that in healthy individuals (P < 0.01). The level of serum DcR3 in HCC patients was correlated with the development of cirrhosis, capsular infiltration and metastasis (P < 0.05). There was a positive correlation between the levels of DcR3 in the serum and HCC tissue (r = 0.395, P < 0.01). The positive rate of DcR3 in the serum was significantly higher than that in HCC tissue (P < 0.05). The sensitivities of single detection of AFP or DcR3 were 82% and 3 76%, respectively. In contrast, the sensitivity of combined detection of AFP and DcR3 rose to 93%.

CONCLUSION: Elevated serum DcR3 may play an important role in the pathogenesis, development, invasion and metastasis of HCC. It may be of great significance for the screening, diagnosis and prognosis of HCC to simultaneously monitor the levels of DcR3 and AFP in the serum of high-risk populations and HCC patients.

Soluble decoy receptor 3 modulates the survival and formation of osteoclasts from multiple myeloma bone disease patients

Decoy receptor 3 (DcR3), a member of the tumor necrosis factor (TNF) receptor superfamily, is known to be involved in cell survival and osteoclast (OC) formation. In this study, we show that malignant plasma cells and T lymphocytes from multiple myeloma (MM) bone disease patients, as well as Karpas 909, a human myeloma cell line, directly produce DcR3. By interacting with FasL, this molecule could inhibit OC apoptosis. In fact, the use of a neutralizing anti-DcR3 antibody induces a reduction of cell viability with a consequent increase of apoptotic cell number, the activation of caspase-8 and -3, and DNA fragmentation. Furthermore, we show that DcR3 supports OC formation in samples from MM patients through the upregulation of RANKL and TNFalpha by T lymphocytes and only TNFalpha by CD14+ cells. In conclusion, our data provide the first evidence of the expression of DcR3 in MM, and the involvement of this molecule in supporting the survival and formation of OCs from MM bone disease patients. The production of DcR3 by T lymphocytes confers these cells a role in the pathogenesis of bone disease associated with MM.

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

Decoy receptor 3 (DcR3), a member of tumor necrosis factor receptor superfamily, has been implicated in tumorigenesis through its abilities to modulate immune responses and induce angiogenesis. Epstein-Barr virus (EBV), a ubiquitous gamma-herpesvirus, is associated with malignancies including nasopharyngeal carcinoma (NPC). Previous studies show that DcR3 is overexpressed in EBV-positive lymphomas and Rta, an EBV transcription activator, can upregulate DcR3 in Burkitt lymphoma cell lines. However, DcR3 expression has not been demonstrated in EBV-associated NPC nor have there been any EBV latent genes linked to DcR3 upregulation. Here, we showed DcR3 was overexpressed in NPC. Higher DcR3 expression score and DcR3-positive rate were found in metastatic NPC than in primary NPC tissues, suggesting DcR3 may enhance cell metastatic potential. This hypothesis is supported by our observation that NPC HONE-1 cells overexpressing DcR3 exhibited significant higher migration and invasion abilities in vitro. We found besides Rta, EBV latent membrane protein (LMP) 1 can upregulate DcR3 via nuclear factor-kappaB and phosphatidylinositol 3-kinase-signaling events. Approximate 75% of LMP1-positive NPC tissues overexpressed DcR3, suggesting LMP1 may enhance DcR3 expression in vivo. Data herein suggested that increasing DcR3 expression by LMP1 not only helps EBV-associated cancer cells gain survival advantage by preventing host immune detection but also increases the chance of cancer metastasis by enhancing cell migration and invasion. All these DcR3-mediated events facilitate normal cells to gain cancer hallmarks.

Combined treatment with denbinobin and Fas ligand has a synergistic cytotoxic effect in human pancreatic adenocarcinoma BxPC-3 cells

BACKGROUND AND PURPOSE

Human pancreatic carcinoma is a highly malignant cancer. Previous studies have shown that the decoy receptor 3 (DcR3) for Fas ligand (FasL) plays significant roles in tumour progression and immune suppression. In the present study, we evaluated the anti-cancer activity of a natural compound, denbinobin (5-hydroxy-3,7-dimethoxy-1,4-phenanthraquinone), through decreasing DcR3 levels in human pancreatic adenocarcinoma cell lines.

EXPERIMENTAL APPROACH

We used immunoprecipitation and ELISA assays to examine DcR3 levels, and used FACS to determine the percentage of cells with a sub-G1 DNA content.

KEY RESULTS

AsPC-1 and BxPC-3 human pancreatic cancer cells express high levels of DcR3. Denbinobin concentration-dependently decreased DcR3 levels in BxPC-3 cells. MTT and flow cytometry assays indicated that BxPC-3 was FasL-resistant because high concentrations (100 ng.mL(-1)) of soluble FasL did not inhibit cell growth. However, combinations of denbinobin (3 micromol.L(-1)) with lower concentrations of soluble FasL (10, 30 and 50 ng.mL(-1)) or membrane-bound FasL, were synergistic on cell growth inhibition and apoptosis. Exogenous excess DcR3 reversed this synergistic effect. We observed no significant increase in the levels of surface Fas, cleaved forms of caspase-8, -3, -9, Bax, Bid, Bcl-xL, cytochrome c or mitochondrial membrane potentials following denbinobin treatment. However, denbinobin treatment increased the levels of apoptosis-inducing factor.

CONCLUSIONS AND IMPLICATIONS

Denbinobin and FasL trigger a synergistic cytotoxic effect in human pancreatic adenocarcinoma cells. Denbinobin mediated a decrease in levels of DcR3, which played a major role in this synergistic effect, and also increased caspase-independent apoptosis, via apoptosis-inducing factor.

Countering tumor-induced immunosuppression during immunotherapy for pancreatic cancer

BACKGROUND

Vaccines for pancreatic cancer have been challenged by a number of factors, especially the immunosuppressive microenvironment within the tumor that allows for escape from immune surveillance.

OBJECTIVE/METHODS

We sought to identify results that define mechanisms of pancreatic-cancer-associated immunosuppression and strategies that might be useful to overcome them thereby resulting in effective immune responses to cancer vaccines capable of deleting pancreatic cancer cells.

RESULTS/CONCLUSION

Immunosuppressive tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSC), and regulatory T cells (Treg) reside in tumors, and their products along with tumor derived products (such as VEGF, TGFbeta and IL-10), create a microenvironment that counters immune activation and attack. Immunotherapy with cancer vaccines must include strategies to modulate these immunosuppressive cell types and tumor byproducts. Clinical trials are beginning to test these strategies.

Decoy receptor 3 is a prognostic factor in renal cell cancer

BACKGROUND

Decoy receptor 3 (DcR3) is a soluble protein that binds to and inactivates the death ligand CD95L. Here, we studied a possible association between DcR3 expression and prognosis in patients with renal cell carcinomas (RCCs).

METHODS

A tissue microarray containing RCC tumor tissue samples and corresponding normal tissue samples was generated. Decoy receptor 3 expression in tumors of 560 patients was examined by immunohistochemistry. The effect of DcR3 expression on disease-specific survival and progression-free survival was assessed using univariate analysis and multivariate Cox regression analysis. Decoy receptor 3 serum levels were determined by ELISA.

FINDINGS

High DcR3 expression was associated with high-grade (P = .005) and high-stage (P = .048) RCCs. The incidence of distant metastasis (P = .03) and lymph node metastasis (P = .002) was significantly higher in the group with high DcR3 expression. Decoy receptor 3 expression correlated negatively with disease-specific survival (P < .001) and progression-free survival (P < .001) in univariate analyses. A multivariate Cox regression analysis retained DcR3 expression as an independent prognostic factor that outperformed the Karnofsky performance status. In patients with high-stage RCCs expressing DcR3, the 2-year survival probability was 25%, whereas in patients with DcR3-negative tumors, the survival probability was 65% (P < .001). Moreover, DcR3 serum levels were significantly higher in patients with high-stage localized disease (P = .007) and metastatic disease (P = .001).

INTERPRETATION

DcR3 expression is an independent prognostic factor of RCC progression and mortality. Therefore, the assessment of DcR3 expression levels offers valuable prognostic information that could be used to select patients for adjuvant therapy studies.

Expression of tumor necrosis factor receptor 6 in the tissue microarrays of gastric carcinoma

AIM: To investigate the expression of tumor necrosis factor receptor 6 (TR6) protein in gastric carcinoma (GC) and its clinical significance.

METHODS: Tissue microarray was constructed using 79 cases of GC tissues, 45 dysplasia (Dys) tissues, 37 intestinal metaplasia (IM) and 42 chronic superficial gastritis (CSG) tissues. Immunohistochemistry was employed to detect the expression of TR6 protein. Statistical analysis was performed to figure out the correlation between TR6 expression and the clinicopathological features of GC.

RESULTS: The positive rate of TR6 protein in GC tissues was significantly higher than that in Dys (χ² = 2.288, P = 0.022), IM (χ² = 2.639, P = 0.008) and CSG tissues (χ² = 3.593, P = 0.000). The expression of TR6 protein in the well-differentiated GC tissues was significantly lower than that in the poorly-differentiated ones (χ² = 2.183, P = 0.029). Moreover, the positive rate of TR6 protein was markedly lower in the groups of TNM stage Ⅰ, Ⅱ or without lymph node metastasis than that in the groups of stage Ⅲ, Ⅳ (χ² = 2.194, P = 0.028) or with lymph node metastasis (χ² = 5.021, P = 0.000). The expression of TR6 was not associated with the age, sex of patients, or the tumor invasive depth.

CONCLUSION: Over-expression of TR6 may play an important role in the pathogenesis, development and metastases of GC. TR6 gene may serve as an important molecular biological indicator in diagnosing and predicating the biological behavior of GC.

Superficial, nodular, and morpheiform basal-cell carcinomas exhibit distinct gene expression profiles

Basal-cell carcinoma (BCC), the most common neoplasm in humans, occurs in a variety of morphological presentations. The mechanisms of BCC development downstream of the initial genetic mutations are not well understood, and different BCC morphological presentations might exhibit distinct gene expression patterns. We investigated superficial (n=8), nodular (n=8), and morpheiform (n=7) BCCs using 21K cDNA microarrays. Global gene expression profiles between respective BCC subtypes, and as compared with normal skin (n=8), were statistically defined by significance analysis of microarrays (SAM). Thirty-seven genes were subsequently validated by quantitative reverse transcriptase-PCR analysis using an expanded set of 31 BCCs. Gene ontology analysis indicated that gene expression patterns of BCC subtypes in multiple biological processes showed significant variation, particularly in genes associated with the mitogen-activated protein kinase (MAPK) pathway. Notably, genes involved in response to DNA-damage stimulus were uniquely upregulated in morpheiform BCCs. Our results indicate a relative similarity in gene expression between nodular and superficial BCC subtypes. In contrast, morpheiform BCCs are more diverse, with gene expression patterns consistent with their more "invasive" phenotype. These data may help us understand the complex behavior of BCC subtypes and may eventually lead to new therapeutic strategies.

Apoptosis of dendritic cells induced by decoy receptor 3 (DcR3)

Decoy receptor 3 (DcR3) is a soluble decoy receptor belonging to the tumor necrosis factor receptor (TNFR) superfamily, and its expression is not only up-regulated in cancer cells derived from various cell lineages, but also correlates with overall survival of patients with cancer. It has been shown that DcR3 sensitize cells of hematopoietic origin to TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis; therefore, we asked whether DcR3 down-regulated host immunity by inducing immune cell apoptosis. We demonstrate that DcR3 induces dendritic cell (DC) apoptosis by activating PKC-delta and JNK subsequently to up-regulate DR5 to recruit Fas-associated death domain (FADD) to propagate the apoptotic signals. The association of FADD with DR5 results in the formation of death-inducing signaling complex (DISC) to trigger the downstream apoptotic signaling cascade. PKC-delta is activated via cross-linking of heparan sulfate proteoglycan (HSPG) on DCs, because recombinant protein containing the heparin-binding domain (HBD) of DcR3 and the Fc portion of IgG(1), the HBD.Fc fusion protein, is also able to trigger DC apoptosis. This provides the first evidence that cross-linking of HSPG on DCs can activate PKC-delta to induce DC apoptosis via the formation of DR5 DISC, and elucidates a novel mechanism of DcR3-mediated immunosuppression.