Overexpression and clinicopathological contribution of DcR3 in bladder urothelial carcinoma tissues

DcR3-associated risk score: correlating better prognosis and enhanced predictive power in colorectal cancer

Decoy receptor 3 (DcR3), a novel soluble protein belonging to the tumor necrosis factor receptor (TNFR) family, has been previously associated with tumorigenesis in various cancers. However, in our study, we unexpectedly found that DcR3 may promote patient survival time in colorectal cancer (CRC). Through an analysis of The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets, we discovered that high levels of DcR3 are associated with improved overall survival (OS) and disease-free survival (DFS) in CRC patients. Further investigation revealed that DcR3 is correlated with favorable clinical features in Metastasis 0 (M0) and stage I/II CRC patients, suggesting it may act as a suppressive factor in CRC. Gene Set Enrichment Analysis (GSEA) demonstrated that the high DcR3 group is enriched in the IL-17 signaling pathway and other immune-related pathways, and Single Sample Gene Set Enrichment Analysis (ssGSEA) revealed a higher abundance of Tumor Infiltrating Lymphocytes (TIL) in the DcR3 high group. To better understand the function of DcR3, we constructed a DcR3-associated riskscore (DARS) model using machine learning, comprising three genes (DPP7, KDM3A, and TMEM86B). The DARS model indicated that high riskscore patients have an unfavorable prognosis, and it is associated with advanced stages (III/IV), T3/4 tumors, and N1/2 lymph node involvement. Additionally, high riskscore group exhibited more frequent gene mutations, such as TTN, MUC16, and SYNE1, with SYNE1 mutation being related to poor prognosis. Intriguingly, DcR3 showed higher expression in the low riskscore group. These results suggest that DcR3 could serve as a potential prognostic biomarker in CRC and may play a crucial role in favorably modulating the immune response in this malignancy.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prognostic value of DcR3 in solid tumors: A meta-analysis

BACKGROUND

Decoy receptor 3 (DcR3) has been reported to be overexpressed in a wide range of solid tumors, suggesting that DcR3 plays a crucial role in the development and progression of cancer. The present meta-analysis assesses the association between DcR3 expression and prognosis in patients with solid tumors.

METHODS

Eligible studies were identified by searching the PubMed, Web of Science, Cochrane Library, EMBASE, Chinese CNKI, and Wan Fang databases. The pooled hazard ratios (HRs) for overall survival (OS) and recurrence-free survival (RFS) were calculated using fixed effects models and random effects models, respectively.

RESULTS

Data from the 16 included studies, with 2209 patients, were reviewed and analyzed. DcR3 overexpression was significantly associated with worse OS in patients with solid tumors, but its expression might not be related to RFS in malignancies.

CONCLUSIONS

Current evidence demonstrates that increased DcR3 expression correlates with a poor prognosis in cancer patients, which suggests that the expression status of DcR3 is a useful biomarker for the prediction of prognosis in patients with solid tumors.

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

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

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

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

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.

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.