Frequent gene amplification and overexpression of decoy receptor 3 in glioblastoma

The dual role of the CD95 and CD95L signaling pathway in glioblastoma

Binding of CD95, a cell surface death receptor, to its homologous ligand CD95L, transduces a cascade of downstream signals leading to apoptosis crucial for immune homeostasis and immune surveillance. Although CD95 and CD95L binding classically induces programmed cell death, most tumor cells show resistance to CD95L-induced apoptosis. In some cancers, such as glioblastoma, CD95-CD95L binding can exhibit paradoxical functions that promote tumor growth by inducing inflammation, regulating immune cell homeostasis, and/or promoting cell survival, proliferation, migration, and maintenance of the stemness of cancer cells. In this review, potential mechanisms such as the expression of apoptotic inhibitor proteins, decreased activity of downstream elements, production of nonapoptotic soluble CD95L, and non-apoptotic signals that replace apoptotic signals in cancer cells are summarized. CD95L is also expressed by other types of cells, such as endothelial cells, polymorphonuclear myeloid-derived suppressor cells, cancer-associated fibroblasts, and tumor-associated microglia, and macrophages, which are educated by the tumor microenvironment and can induce apoptosis of tumor-infiltrating lymphocytes, which recognize and kill cancer cells. The dual role of the CD95-CD95L system makes targeted therapy strategies against CD95 or CD95L in glioblastoma difficult and controversial. In this review, we also discuss the current status and perspective of clinical trials on glioblastoma based on the CD95-CD95L signaling pathway.

Integrative analysis of TNFRSF6B as a potential therapeutic target for pancreatic cancer

Background

Pancreatic cancer is one of the most lethal malignant tumors worldwide with poor outcomes. Previous studies have shown that tumor necrosis factor receptor superfamily member 6b (TNFRSF6B) plays an important role in cancer progression and immunosuppression. However, the mechanisms by which TNFRSF6B influence pancreatic cancer, and the regulatory networks involved remain to be further studied.

Methods

This study analyzed the mRNA information and clinical data of patients from The Cancer Genome Atlas (TCGA) and the ONCOMINE databases. The gene co-expression data regarding TNFRSF6B was obtained from the c-BioPortal and used to explore the functional network of TNFRSF6B in pancreatic cancer, as well as its function in tumor immunity. Short hairpin (sh) RNA knock-down experiments were performed to examine the functional roles of TNFRSF6B in pancreatic cancer cell lines.

Results

The expression of TNFRSF6B was elevated in pancreatic cancer tissues compared to normal pancreatic tissues, and its high expression was associated with poor prognosis of patients with pancreatic cancer. TNFRSF6B was found to be widely involved in cell cycle processes, apoptosis, apoptosis signaling pathways, immune responses, and responses to interferon. Knock-down of TNFRSF6B expression inhibited pancreatic cancer cell proliferation and invasion in vitro. Moreover, carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) was found to be co-expressed with TNFRSF6B, and there was a positive correlation between these molecules in pancreatic cancer cells.

Conclusions

This report suggested that TNFRSF6B has a critical role in the progression and metastasis of pancreatic cancer. These findings provide novel insights into the role of TNFRSF6B in the functional network of pancreatic cancer, and suggest that TNFRSF6B may be a potential therapeutic target.

Diuron exposure and Akt overexpression promote glioma formation through DNA hypomethylation

BACKGROUND

Diuron is an environmental component listed as a likely human carcinogen. Several other studies report that diuron can be oncogenic for bladder, urothelial, skin, and mammary cells. No study mentions the putative effect of diuron on the glioma occurrence.

OBJECTIVES

We here wanted to investigate the effects of diuron exposure on the glioma occurrence while wishing to incriminate a putative implication of DNA methylation modulation in this process.

METHODS

In in vivo model of glioma, diuron exposure was firstly compared or combined with oncogenic overexpressions already known to promote gliomagenesis. ELISA quantifying the 5-methylcytosine level on DNA was performed to examine the global DNA methylation level. Quantitative real-time polymerase chain reaction and proximity ligation in situ assay were performed to identify the molecular causes of the diuron-induced changes of DNA methylation. The signatures diuron-induced changes of DNA methylation were analyzed in a cohort of 23 GBM patients.

RESULTS

Diuron exposure is not sufficient to promote glioma, such as the oncogenic overexpression of Akt or Ras. However, the combination of diuron exposure and Akt overexpression promotes glioma. We observed that the diuron/Akt-induced glioma is characterized by three phenotypic signatures characterizing cancer cells: a global DNA hypomethylation, a loss of sensitivity to cell death induction, and a gain of signals of immune escape. Our data associated these phenotypes with three aberrant DNA methylation signatures: the LLT1, PD-L1, and Bcl-w hypomethylations. Strikingly, we observed that these three concomitant hypomethylations were only observed in GBM patients having a potential exposure to diuron via their professional activity.

CONCLUSIONS

As single player, diuron is not an oncogenic of glioma, but it can participate to the glioma formation in association with other events (also devoid of oncogenic property as single player) such as Akt overexpression.

Anti-cancer effects of the HuR inhibitor, MS-444, in malignant glioma cells

Glioblastoma is a highly malignant and typically fatal tumor of the central nervous system. The tumor is characterized by marked cellular and molecular heterogeneity, including a subpopulation of brain tumor initiating cells (BTICs) that are highly resistant to radiation and chemotherapy. We previously reported that the RNA-binding protein HuR is: (1) overexpressed in glioblastoma, (2) necessary for tumor growth in vivo, and (3) a positive regulator of tumor-promoting genes in glioblastoma. These findings provide strong evidence that HuR might be a viable therapeutic target in glioblastoma. In this report, we investigated the effects of MS-444, a small molecule inhibitor of HuR, in xenograft-derived human glioblastoma cells and BTICs. We found that MS-444 treatment of glioblastoma cells resulted in loss of viability and induction of apoptosis, with evidence implicating death receptor 5. BTICs were particularly sensitive to MS-444. At sub-lethal doses, MS-444 attenuated invasion of glioblastoma cells and BTICs in a transwell model. At the molecular level, MS-444 treatment led to an attenuation of mRNAs in different tumor promoting pathways including angiogenesis, immune evasion and suppression of apoptosis. Although cytoplasmic HuR was reduced with MS-444 treatment, the attenuation of mRNAs could not be explained by RNA destabilization. In summary, this report provides proof of concept that small molecule inhibition of HuR could be a viable approach for treatment of glioblastoma.

Fragile X mental retardation protein promotes astrocytoma proliferation via the MEK/ERK signaling pathway

Objective

To examine the association between fragile X mental retardation protein (FMRP) expression and astrocytoma characteristics.

Methods

Pathologic grade and expressions of glial fibrillary acidic protein (GFAP), Ki67 (proliferation marker), and FMRP were determined in astrocytoma specimens from 74 patients. Kaplan-Meier survival analysis was undertaken. Pathologic grade and protein levels of FMRP were determined in 24 additional patients with astrocytoma and 6 controls (cerebral trauma). In cultured U251 and U87 cell lines, the effects of FMRP knock-down on cell proliferation, AKT/mTOR/GSK-3β and MEK/ERK signaling were studied. The effects of FMRP knock-down on the volumes and weights of U251 cell-derived orthotopic tumors in mice were investigated.

Results

In patients, FMRP expression was increased in grade IV (5.1-fold, P<0.01) and grade III (3.2-fold, P<0.05) astrocytoma, compared with controls. FMRP and Ki67 expressions were positively correlated (R²=0.877, P<0.001). Up-regulation of FMRP was associated with poorer survival among patients with FMRP integrated optical density >30 (P<0.01). In astrocytoma cell lines, FMRP knock-down slowed proliferation (P<0.05), inhibited total MEK levels P<0.05, and reduced phosphorylation of MEK (Ser217/221) and ERK (Thr202/Tyr204) (P<0.05). In mice with orthotopic tumors, FMRP knock-down decreased FMRP and Ki67 expressions, and reduced tumor volume and weight (36.3% or 61.5% on day 15, both P<0.01). Also, phosphorylation of MEK (Ser217/221) and ERK (Thr202/Tyr204), and total MEK in xenografts were decreased in sh-FMRP xenografts compared with non-transfected ones (all P<0.05).

Conclusion

Enhanced FMRP expression in astrocytoma may promote proliferation through activation of MEK/ERK signaling.

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.

Identification and preclinical evaluation of the small molecule, NSC745887, for treating glioblastomas via suppressing DcR3-associated signaling pathways

The small-molecule naphtha [2,3-f]quinoxaline-7,12-dione (NSC745887) can effectively inhibit the proliferation of various cancers by trapping DNA-topoisomerase cleavage. The aim of this study was to elucidate cellular responses of NSC745887 in human glioblastoma multiforme (GBM, U118MG and U87MG cells) and investigate the underlying molecular mechanisms. NSC745887 reduced the cell survival rate and increased the sub-G₁ population in dose- and time-dependent manners in GBM cells. Moreover, NSC745887 increased expression of γH2AX and caused DNA fragmentation leading to DNA damage. Furthermore, Annexin V/propidium iodide and Br-dTP staining showed the apoptotic effect of NSC745887 in GBM cells. DNA repair proteins of ataxia-telangiectasia mutated (ATM), ATM and Rad3-related, and decoy receptor 3 also decreased with NSC745887 treatment. In addition, NSC745887 caused apoptosis by the caspase-8/9-caspase-3-poly(ADP-ribose) polymerase cascade. An in vivo study indicated that NSC745887 suppressed the [¹⁸F]-FDG-specific uptake value in brain tumors. Histological staining also indicated a decrease in Ki-67 and increases in γH2AX and cleaved caspase-3 in the brain tumor area. These data provide preclinical evidence for NSC745887 as a potential new small molecule drug for managing glioblastomas.

Effect of DcR3-specific siRNA on cell growth suppression and apoptosis induction in glioma cells via affecting ERK and AKT

BACKGROUND

Previously, we found that the expression of decoy receptor 3 (DcR3) in gliomas was significantly upregulated compared to normal brain tissues. However, the effect of DcR3-specific small interfering RNA (siRNA) on cell biological function of glioma cells remains incompletely understood.

OBJECTIVE

The aim of this study was to explore the effect of DcR3 siRNA on cell growth and apoptosis of glioma cells and to investigate the potential downstream pathways affected by DcR3.

METHODS

DcR3-specific siRNA was transfected into three glioma cell lines (U251MG, LN-308, and U87MG) using combiMAGnetofection method. MTS tetrazolium assay and fluorimetric resorufin viability assay were used to assess the growth of glioma cells. Then, apoptosis was examined using the Hoechst 33342/propidium iodide double-staining assay and fluorescent caspase-3/7 assay. Meanwhile, Western blot was performed to explore the probable pathway by which DcR3-specific siRNA acts in glioma cells. Also, microarray dataset analysis was applied to analyze the potential function of DcR3 in glioma.

RESULTS

The DcR3-specific siRNA had a potent effect on cell growth and apoptosis of all three glioma cells tested, and the effects were time dependent. Among these three glioma cell lines, U251MG had the most significant effect with regard to growth inhibition and apoptosis induction. MTS assay showed that the proliferation rate at 72 and 96 hours after the transfection was 76.333%±5.131% (t=7.611, P=0.002) and 64.333%±5.859% (t=10.983, P<0.001), respectively. The viability rate of U251MG cells was 80.667%±2.309% (t=12.302, P<0.001) and 62.333%±2.082% (t=21.213, P<0.001) at 72 and 96 hours posttreatment, respectively. The caspase-3/7 activity of U251MG cells was 2.76 (t=-6.601, P=0.003) and 4.75 (t=-9.189, P=0.001) folds that of the mock control at 72 and 96 hours, respectively. The apoptosis rate was increased to 1.85 (t=-2.496, P=0.067) and 3.93 (t=-12.587, P<0.001) folds at 72 and 96 hours after transfection, respectively. Furthermore, the levels of phospho-ERK1/2 and phospho-AKT were significantly downregulated after DcR3 silencing.

CONCLUSION

The DcR3-specific siRNA could efficiently inhibit growth and induce apoptosis of cells via affecting ERK and AKT. Hence, DcR3-specific siRNA treatment could act as a supplementary targeted therapy strategy for gliomas.

Expression and clinicopathological implication of DcR3 in lung cancer tissues: a tissue microarray study with 365 cases

BACKGROUND

Decoy receptor 3 (DcR3) has been reported to be involved in different cancers. However, few related researches have been accomplished on the role of DcR3 in lung cancer.

OBJECTIVE

To explore the expression level and clinicopathological implication of DcR3 protein in lung cancer tissues.

MATERIALS AND METHODS

Immunohistochemistry was used to examine DcR3 protein expression in lung cancer (n=365) and normal lung tissues (n=26). The relationships between DcR3 expression and clinical parameters were further investigated. Furthermore, the diagnostic and clinicopathological value of DcR3 mRNA was analyzed based on The Cancer Genome Atlas database in lung cancer patients.

RESULTS

Compared to normal lung tissues, DcR3 expression was significantly higher in lung cancer (P=0.007) tissues, including small-cell lung cancer (P=0.001) and non-small-cell lung cancer (P=0.008). In addition, DcR3 expression was related to tumor-node-metastasis (TNM) stage (P<0.001), tumor diameter (P=0.007), distant metastasis (P<0.001), and lymph node metastasis (P<0.001) in lung cancers. When concerning non-small-cell lung cancer, consistent correlations between DcR3 expression and TNM stage (P<0.001), tumor diameter (P=0.019), distant metastasis (P<0.001), and lymph node metastasis (P<0.001) were found. Simultaneously, in small-cell lung cancer, TNM stage (P=0.004) and lymph node metastasis (P=0.005) were also associated with DcR3 expression. Additionally, receiver operator characteristic curve revealed that the area under curve (AUC) of DcR3 was 0.637 (95% confidence interval [CI] 0.531-0.742) for lung cancer. Furthermore, DcR3 was overexpressed in both adenocarcinoma and squamous cell carcinoma tissues than in noncancerous lung tissues (all P<0.0001) based on the data from The Cancer Genome Atlas. AUC of DcR3 was 0.726 (95% CI 0.644-0.788) for lung adenocarcinoma patients and 0.647 (95% CI 0.566-0.728) for squamous cell carcinoma patients. DcR3 expression was also related to the overall survival (P<0.001) and disease-free survival (P<0.001) of lung adenocarcinoma according to the data from The Cancer Genome Atlas.

CONCLUSION

Our study confirms that DcR3 might be involved in the tumorigenesis and deterioration of lung cancer. Therefore, the detection of DcR3 gains the potential to be applied in the clinic for screening and progression prediction of lung cancer.

Overexpression of DcR3 and its significance on tumor cell differentiation and proliferation in glioma

Background. Overexpression of decoy receptor 3 (DcR3) have been reported in various classes of malignancies. However, its expression and clinicopathological contribution in gliomas has not been fully elucidated. Objective. To explore the expression and clinical significance of DcR3 protein in relation to tumor cell differentiation and proliferation in glioma cell lines and tissues. Methods. One hundred and twenty-five samples of glioma patients and 18 cases of normal brain tissues were recruited. The expression of DcR3 protein was detected using immunohistochemistry. Tumor differentiation was assessed by histologic characters and the status of glial fibrillary acidic protein (GFAP). Tumor cell labeling indexes (LIs) of Ki-67 and PCNA were also obtained. The relationship between the DcR3 level and clinicopathological features was investigated, including tumor differentiation, LIs, and survival. Meanwhile, the expression of DcR3 protein was also measured in the supernatants of 8 glioma cell lines and glioma cells freshly prepared from 8 human glioblastoma specimens by using western blot. Results. The level of DcR3 protein in gliomas was significantly higher than that in normal brain tissues (P < 0.01). DcR3 expression showed positive correlations with tumor pathological grade (r = 0.621, P < 0.01) and negative with GFAP expression (r = −0.489, P < 0.01). Furthermore, there were positive correlations between DcR3 expression and Ki-67, PCNA LIs (r = 0.529, P < 0.01; r = 0.556, P < 0.01). The survival in the DcR3 negative group was 50 ± 1.79 months, longer than that of the DcR3 positive group (48.36 ± 2.90), however, without significance (P = 0.149). Different levels of DcR3 could also be detected in the culturing supernatants of all the 8 glioma cell lines and glioma cells freshly obtained from 8 human glioblastoma specimens. Conclusions. The overexpression of DcR3 might play a crucial role in the tumorigenesis, differentiation, and proliferation of glioma.

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.

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.

Clinical significance of expression and amplification of the DcR3 gene in pancreatic carcinomas

This study aimed to investigate the clinical significance of expression and amplification of decoy receptor 3 (DcR3) in pancreatic carcinomas (PC). mRNA expression was detected by PQ-PCR, and amplification was determined. DcR3 protein expression was detected by immunohistochemistry and ELISA. Correlations between DcR3 expression and clinical pathological factors were analyzed. The relative amount of DcR3 in PC tissues and non-cancerous tissues showed a statistically significant difference, 21 cases displaying more than two fold DcR3 amplification, while no such amplification was found in normal pancreatic tissues. DcR3 positive cell staining was located in the cytoplasm. The positive rate of DcR3 in PC and non-cancerous tissues showed a significant difference. DcR3 mRNA expression was correlated with clinical staging, size of the tumor, lymph node metastasis and histological staging, while protein expression was correlated with clinical data like tumor size. DcR3 gene amplification only correlated with tumor size. The level of DcR3 in serum of the PC resectable group before operation was 72.2±10.2 pg/ml, showing a significant difference compared to gallbladder carcinoma group (GC) or pancreatic benign tumor (PBT) group (P <0.01). In conclusion, DcR3 amplification is correlated with DcR3 expression in PC tissues, especially those clinical pathological factors which reflect tumor progression. Assessment of DcR3 level in sera of PC patients may be helpful for the early diagnosis and prognostic judgement.

Fine mapping analysis of a region of 20q13.33 identified five independent susceptibility loci for glioma in a Chinese Han population

Genome-wide association studies have identified the susceptibility single nucleotide polymorphisms (SNPs) of glioma at chromosome 20q13.33, and the replication study conducted among Chinese Han population also confirmed the susceptibility locus rs6010620 is located in this region. To identify other genetic variants in 20q13.33, we genotyped 13 common tagging SNPs and imputed 86 additional SNPs in a region ∼100 kb at 20q13.33 among 1027 controls and 987 cases. Among 99 SNPs, five independent susceptibility loci (20-62315594 in RTEL1, 20-62335293 in adenosine diphosphate ribosylation factor-related protein 1, rs3761121 in ZGPAT, rs1058319 in SLC2A4RG and rs5019252 in ZBTB46) were identified for glioma. Two of the five SNPs (20-62335293, P = 3.09 × 10(-10) and rs1058319, P = 1.26 × 10(-11)) satisfied the threshold of genome-wide significance (P < 10(-8)). Further stratified analysis revealed that 20-62315594 was only significantly associated with glioblastoma (GBM) risk [P = 1.71 × 10(-8) for trend test, adjusted odds ratio (OR) = 1.99, 95% confidence interval (CI) = 1.57-2.52]. Other four SNPs were significantly associated with both GBM and astrocytoma. The risk of glioma increased with the increase of the number of risk alleles (P = 1.94 × 10(-11), for trend test, adjusted OR = 1.43, 95% CI = 1.29-1.58), and the individuals who carried 7-10 risk alleles had a 2.64-fold increased risk of glioma development compared with those who carried 0 risk allele (P = 8.71 × 10(-7), adjusted OR = 2.64, 95% CI = 1.79-3.88). Our results indicated a complex effect contributing to glioma risk at 20q13.33, which may provide a new insight into glioma development. Both variants and genes in this region should be considered in future studies designed to investigate the biological functions.

Serum decoy receptor 3 level: a predictive marker for nodal metastasis and survival among oral cavity cancer patients

BACKGROUND

Validating markers for prediction of nodal metastasis could be beneficial in treatment of oral cavity cancer. Decoy receptor 3 (DcR3), locus on 20q13, functions as a death decoy inhibiting apoptosis mediated by the tumor necrosis factor receptor (TNFR) family.

METHODS

This study analyzed the serum level of DcR3 in relationship to the clinical parameters of oral cavity cancer patients together with detection of DcR3 genomic copy number in primary and recurrent tumors.

RESULTS

Elevated serum DcR3 was associated with nodal metastasis and worse prognosis. Gain of DcR3 copy number was detected in 17% of primary tumor tissue but not found in healthy areca chewers. Tissue from recurrent tumors showed more frequent DcR3 copy number alteration (48%) than the paired primary tumor tissue.

CONCLUSIONS

Serum DcR3 level is a predictor for the nodal metastasis and survival among oral cavity cancer patients and the DcR3 copy number alteration could underlie oral carcinogenesis progression.

Modulation of CCAAT/enhancer binding protein homologous protein (CHOP)-dependent DR5 expression by nelfinavir sensitizes glioblastoma multiforme cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)

Human glioblastoma multiforme cells demonstrate varying levels of sensitivity to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. Endoplasmic reticulum (ER) stress has been shown to trigger cell death through apoptosis. We therefore pursued a strategy of integrating clinically relevant investigational agents that cooperate mechanistically through the regulation of ER stress and apoptosis pathways. Nelfinavir belongs to the protease inhibitor class of drugs currently used to treat patients with HIV and is in clinical trials as an anti-tumor agent. We found that Nelfinavir treatment led to ER stress-induced up-regulation of the DR5 receptor. This transactivation was mediated by the transcription factor CCAAT/enhancer binding protein homologous protein (CHOP). We also determined that ER stress-induced ATF4 up-regulation was responsible for modulation of CHOP. In contrast, DR4 receptor expression was unchanged by Nelfinavir treatment. Combining Nelfinavir with TRAIL led to a significantly enhanced level of apoptosis that was abrogated by siRNA silencing of DR5. We provide evidence that Nelfinavir-induced ER stress modulates DR5 expression in human glioblastoma multiforme cells and can enhance TRAIL efficacy. These studies provide a potential mechanistic rationale for the use of the Food and Drug Administration-approved agent Nelfinavir in combination with DR5 agonists to induce apoptosis in human malignancies.

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.

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.

Genome-wide association study identifies five susceptibility loci for glioma

To identify risk variants for glioma, we conducted a meta-analysis of two genome-wide association studies by genotyping 550K tagging SNPs in a total of 1,878 cases and 3,670 controls, with validation in three additional independent series totaling 2,545 cases and 2,953 controls. We identified five risk loci for glioma at 5p15.33 (rs2736100, TERT; P = 1.50 x 10(-17)), 8q24.21 (rs4295627, CCDC26; P = 2.34 x 10(-18)), 9p21.3 (rs4977756, CDKN2A-CDKN2B; P = 7.24 x 10(-15)), 20q13.33 (rs6010620, RTEL1; P = 2.52 x 10(-12)) and 11q23.3 (rs498872, PHLDB1; P = 1.07 x 10(-8)). These data show that common low-penetrance susceptibility alleles contribute to the risk of developing glioma and provide insight into disease causation of this primary brain tumor.

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.

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.

Gene amplification is a poor prognostic factor in anaplastic oligodendrogliomas

Various gene amplifications have been observed in gliomas. Prognostic-genomic correlations testing simultaneously all these amplified genes have never been conducted in anaplastic oligodendrogliomas. A set of 38 genes that have been reported to be amplified in gliomas and investigated as the main targets of amplicons were studied in a series of 52 anaplastic oligodendrogliomas using bacterial artificial chromosome-array based comparative genomic hybridization and quantitative polymerase chain reaction. Among the 38 target genes, 15 were found to be amplified in at least one tumor. Overall, 27% of anaplastic oligodendrogliomas exhibited at least one gene amplification. The most frequently amplified genes were epidermal growth factor receptor (EGFR) and cyclin-dependent kinase 4/sarcoma amplified sequence (CDK4/SAS) in 17% and 8% of anaplastic oligodendrogliomas, respectively. Gene amplification and codeletion of chromosome arms 1p/19q were perfectly exclusive (p = 0.005). In uni- and multivariate analyses, gene amplification was a negative prognostic factor for progression-free survival and overall survival in anaplastic oligodendrogliomas, providing complementary information to the classic prognostic factors identified in anaplastic oligodendrogliomas (extent of surgery, KPS, and chromosome arms 1p/19q status).

Supratentorial primitive neuroectodermal tumors of the central nervous system frequently harbor deletions of theCDKN2A locus and other genomic aberrations distinct from medulloblastomas

Supratentorial primitive neuroectodermal tumors (stPNETs) and medulloblastomas have long been thought to arise from a common cell type in the subventricular germinal matrix. Because of the infrequent occurrence of stPNETs, little is known about their genetic background. Here, we performed a genome-wide screening for DNA copy-number aberrations in 10 supratentorial PNETs using array-based comparative genomic hybridization (array-CGH). Comparing our findings with data from a previous array-CGH study on 47 medulloblastomas, we identified differences in the frequency of copy-number losses at chromosome regions 1p12-22.1 and 9p, and gains at 19p, all of them more frequently occurring in stPNETs. In contrast to previous reports, we detected chromosome 17 aberrations by array-CGH in 2/10 stPNETs. To validate our findings obtained by array-CGH, we analyzed the loci of interest by fluorescence in situ hybridization in an independent set of 11 stPNETs and found deletions of 9p21 in 5/11 tumors of the second set, three of them being homozygous. All 9p21 deletions were associated with loss of CDKN2A protein expression. Altogether, CDKN2A deletions were detected in 7/21 stPNETs including four homozygous deletions, whereas such deletions were only found in 4/112 medulloblastomas, all of these being heterozygous (P < 0.001). Gains of 19p (14% vs. 0% in medulloblastomas, P = 0.02) were found to be significantly more frequent in stPNETs, whereas gains of 17q (14% vs. 45% in medulloblastomas, P = 0.02) were confirmed to be more frequent in medulloblastomas. These data further support the hypothesis of two different tumor entities of embryonal neuroepithelial tumors with characteristic genetic aberrations. (c) 2007 Wiley-Liss, Inc.