Gut microbial evidence chain in high-salt diet exacerbates intestinal aging process.

Although excessive salt consumption appears to hasten intestinal aging and increases susceptibility to cardiovascular disease, the molecular mechanism is unknown. In this study, mutual validation of high salt (HS) and aging fecal microbiota transplantation (FMT) in C56BL/6 mice was used to clarify the molecular mechanism by which excessive salt consumption causes intestinal aging. Firstly, we observed HS causes vascular endothelial damage and can accelerate intestinal aging associated with decreased colon and serum expression of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and increased malondialdehyde (MDA); after transplantation with HS fecal microbiota in mice, vascular endothelial damage and intestinal aging can also occur. Secondly, we also found intestinal aging and vascular endothelial damage in older mice aged 14 months; and after transplantation of the older mice fecal microbiota, the same effect was observed in mice aged 6-8 weeks. Meanwhile, HS and aging significantly changed gut microbial diversity and composition, which was transferable by FMT. Eventually, based on the core genera both in HS and the aging gut microbiota network, a machine learning model was constructed which could predict HS susceptibility to intestinal aging. Further investigation revealed that the process of HS-related intestinal aging was highly linked to the signal transduction mediated by various bacteria. In conclusion, the present study provides an experimental basis of potential microbial evidence in the process of HS related intestinal aging. Even, avoiding excessive salt consumption and actively intervening in gut microbiota alteration may assist to delay the aging state that drives HS-related intestinal aging in clinical practice.

CD137 agonist induces gastric cancer cell apoptosis by enhancing the functions of CD8+ T cells via NF-κB signaling.

BACKGROUND: CD137 is a target for tumor immunotherapy. However, the role of CD137 in gastric cancer (GC), especially in inducing GC cell apoptosis, has not been studied. METHODS: Foxp3+ and CD8+ T cells in GCs were investigated using immunohistochemistry (IHC). CD137 expression in GCs was detected using flow cytometry, IHC and immunofluorescence (IF). Peripheral blood mononuclear cells (PBMCs) and CD8+ T cells isolated from peripheral blood were stimulated with a CD137 agonist in vitro. CD8+ T cell proliferation and p65 expression was examined using flow cytometry. P65 nuclear translocation was analyzed using IF. IL-10, TGF-ß, IFN-γ, perforin and granzyme B were detected using real-time quantitative PCR (real-time PCR). PBMCs and primary GC cells were cocultured and stimulated with a CD137 agonist in vitro. Apoptosis of primary GC cells was detected using flow cytometry. RESULTS: Our data demonstrated that GC tumors showed characteristics of an immunosuppressive microenvironment. CD137 was predominantly expressed in CD8+ T cells in GCs and had a positive correlation with tumor cell differentiation. The CD137 agonist promoted CD8+ T cell proliferation and increased the secretion of IFN-γ, perforin and granzyme B, which induced primary GC cell apoptosis. Mechanistically, this study found that the CD137 agonist induced NF-κB nuclear translocation in CD8+ T cells. CONCLUSION: Our results demonstrated that a CD137 agonist induced primary GC cell apoptosis by enhancing CD8+ T cells via activation of NF-κB signaling.

NEDD9 expression is correlated with epithelial-to-mesenchymal transition markers in colorectal cancer.

The epithelial-to-mesenchymal transition (EMT) is a critical step in tumor metastasis. NEDD9 has been shown to be an oncogene in colorectal cancer. However, little is known about the relationship between NEDD9 and EMT in colorectal cancer metastasis. A total of 63 pairs of freshly frozen colorectal cancer tissues and adjacent noncancerous tissues were evaluated for NEDD9 gene expression using quantitative real-time PCR. The expression of NEDD9 and three epithelial-mesenchymal transition (EMT)-related proteins (E-cadherin, ß-catenin and vimentin) was examined in 122 colorectal cancers by immunohistochemistry. The expression of NEDD9 was markedly increased in colorectal cancer tissues compared with adjacent noncancerous tissues. The expression level of NEDD9 was positively correlated and TNM stage but not with other clinicopathological features of colorectal tumors. Furthermore, the expression of NEDD9 was strongly associated with the loss of epithelial marker E-cadherin and acquired expression of the mesenchymal markers nuclear ß-catenin and vimentin. These findings suggested that NEDD9 might promote EMT and the progression of colorectal cancer, and thus may be a potential therapeutic target of colorectal cancers.

DLC-1 is a candidate biomarker methylated and down-regulated in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDA) is one of the most aggressive malignancies in humans, and its prognosis is generally poor even after surgery. Many advances have been made to understand the pathogenesis of PDA; however, the molecular mechanisms that lead to pancreatic carcinogenesis are still not clearly understood. The aims of this study were to investigate the relationship between DLC-1 methylation status and clinicopathological characteristics of PDA patients and evaluate the role of DLC-1 methylation status in PDA. The expression of DLC-1 mRNA in PDA tissues was analyzed by real-time PCR. The methylation status of DLC-1 was analyzed by methylation-specific polymerase chain reaction (MSP). Furthermore, we determined the prognostic importance of DLC-1 methylation status in PDA patients. Our results showed that the expression level of DLC-1 mRNA in PDA tissues was lower than that in non-cancerous tissues. The rate of DLC-1 promoter methylation was significantly higher in PDA tissues than in adjacent non-cancerous tissues (p < 0.001). Downregulation of DLC-1 was strongly correlated with promoter methylation (P = 0.003). The presence of DLC-1 methylation in PDA tissue samples was significantly correlated with clinical stage (P = 0.005), histological differentiation (P = 0.05), and lymph node metastasis (P = 0.006). Kaplan-Meier survival analysis showed that DLC-1 methylation status was inversely correlated with overall survival of the PDA patients. Further, Cox multivariate analysis indicated that DLC-1 methylation status was an independent prognostic factor for the overall survival rate of PDA patients. In conclusion, our data suggest that downregulation of DLC-1 may be explained by DNA methylation; DLC-1 may be a biomarker for PDA.