The Association of EBV and Gastric Cancer

The present study aimed to investigate the clinicopathological features of EBV positive and EBV negative gastric cancer patients and the expression levels of proliferative, apoptotic and cell signaling proteins in tissues samples from these patients. The biological role of EBV infection was assessed in gastric cancer. Results: EBV was localized in the nuclei of gastric cancer cells (positive rate 6.86%). The infection rate of EBV in normal gastric mucosal cells, which were adjacent to cancer tissues, was 0. The difference noted was significant (P = 0. 023). The expression levels of caspase-3 (P = 0.0423), FASL (P = 0.00297) and cyclin D1 (P = 0.0345) proteins were significantly different in EBV positive and negative gastric cancer tissues. When the parameters gender, age, Lauren classification, histological grade, early and advanced tumor stage, vascular and nerve invasion, TNM grade and survival status were compared, the maximum tumor diameter, number of lymph node metastasis, caspase-8, Ki67 and P53 protein expression did not reveal significant differences. Bcl-2 protein expression was positive in only one gastric cancer cell sample and negative in the other gastric cancer cell samples as well as in the corresponding normal gastric mucosal epithelial cells. However, significant differences were noted with regard to the positive expression of Bcl-2 in the immune cells of gastric cancer and adjacent tissues (P = 1.17749E-39). The expression levels of Bcl-2 in the immune cells of EBV positive and EBV negative gastric cancer tissues were not significantly different. The expression levels of caspase-8, caspase-3, FASL, Ki67, cyclin D1 and P53 proteins in gastric cancer cells were significantly different compared to those of normal gastric mucosal cells derived from adjacent tissues (P < 0.05). These findings were noted in both EBV positive and/or EBV negative gastric cancer cases (P < 0.05). The survival time of the patients with EBV positive gastric cancer was higher than that of the patients with EBV negative gastric cancer, whereas the differences were not significantly different. The aforementioned results suggested that the EBV virus may directly infect cancerous cells but not normal gastric mucosal cells. With the exception of caspase-3, the expression levels of the proteins FASL and cyclin D1 were closely associated with EBV-positive gastric cancer. EBV did not have a specific effect on the expression of the signaling molecules associated with proliferation and apoptosis of gastric cancer cells. Its effect on gastric cancer cells may be associated with other factors and requires further discussion. No significant differences were noted in the clinicopathological features of EBV positive compared to those of EBV negative gastric cancer patients. However, the prognosis of EBV positive gastric cancer patients was better than that of EBV negative gastric cancer patients. The mechanism of action associated with these processes requires further verification.

Epigenetic silencing of microRNA-204 by Helicobacter pylori augments the NF-κB signaling pathway in gastric cancer development and progression

Helicobacter pylori infection induces gastric cancer (GC) development through a progressive cascade; however, the roles of the microRNAs that are involved in the cascade and the underlying mechanisms are still unclear. Here, we found that microRNA-204 was suppressed in gastric mucosal cells in response to H.pylori infection and downregulated in GC tissues due to aberrant methylation of the promoter of its host gene, TRPM3. Helicobacter pylori induced a progressive downregulation of microRNA-204 from superficial gastritis to intestinal metaplasia, with an accompanying increment of the methylated levels of CpG sites in the TRPM3 promoter. With the GC cellular models of AGS, MGC-803 or BGC-823, we found that microRNA-204 suppressed the tumor necrosis factor (TNF)-α-induced activation of NF-κB signaling pathways and, in animal models, inhibited tumor growth and metastasis. The conditional supernatant of microRNA-204 overexpression GC cells led to reduced tube formation of human umbilical vein endothelial cells. A target gene for microRNA-204 was BIRC2, and in GC cells, BIRC2 knockdown recapitulated the biological phenotype of microRNA-204 overexpression. BIRC2 overexpression promoted the metastasis of GC cells and rescued the inhibition activities of microRNA-204 on cell migration and the NF-κB signaling pathway. Moreover, lower microRNA-204 and higher BIRC2 expression levels were associated with a poorer prognosis of GC patients. These results demonstrate that epigenetic silencing of microRNA-204 induced by H.pylori infection augments the NF-κB signaling pathway in H.pylori-induced gastritis and GC, potentially providing novel intervention targets for these diseases. MicroRNA-204 was epigenetically down-regulated by H. pylori infection in gastric mucosal cells. It led to enhanced BIRC2 expression level and BIRC2/TNF-a/NF-kB signaling pathway activities, which promoted angiogenesis and metastasis of gastric cancer cells.

Gramicidin inhibits human gastric cancer cell proliferation, cell cycle and induced apoptosis

Background Gastric cancer is a common malignant tumor with high morbidity and mortality worldwide, which seriously affects human health. Gramicidin is a short peptide antibiotic which could be used for treating infection induced by bacteria or fungi. However, the anti-cancer effect of gramicidin on gastric cancer cells and its underlying mechanism remains largely unknown. Results Gastric cancer cells SGC-7901, BGC-823 and normal gastric mucosal cells GES-1 were treated with different concentrations of gramicidin respectively. The results of CCK-8 experiment revealed cellular toxicity of gramicidin to cancer cells while cell colony formation assay showed that gramicidin significantly inhibited the proliferation of gastric cancer cells, but had little effect on normal gastric mucosal cells. In addition, the wound healing assay showed that gramicidin inhibited the migration of SGC-7901 cell. Meanwhile, apoptosis and cell cycle analysis revealed that gramicidin induced cell apoptosis with G2/M cell cycle inhibition. Furthermore, western blot analysis demonstrated that gramicidin down-regulated the expression of cyclinD1 and Bcl-2 as well as the FoxO1 phosphorylation. Conclusions The current study illustrated the anti-tumor activity of gramicidin on gastric cancer cells, providing a possibility for gramicidin to be applied in clinical practice for the treatment of gastric cancer.

A New Participant in the Pathogenesis of Alcoholic Gastritis: Pyroptosis

Background/Aims: Alcohol abuse exerts deleterious effects on the internal organs of the body, and alcohol-related gastritis is a common disease for which prompt treatment is essential to prevent the condition from growing worse. However, the therapeutic methods have some adverse effects. Determining the pathogenic mechanisms of alcoholic gastritis is therefore essential. Methods: The MTT assay was developed in order to determine the optimal concentration of alcohol needed to treat gastric mucosal cells. The effects of alcohol on the gastric mucosal cells were determined by qRT-PCR and western blot. The release of IL-1β and IL-18 were determined by ELISA assay. The immunofluorescence assay was used to detect caspase-1 activation levels, while immunohistochemical assay and HE staining were performed to identify the effectiveness of the caspase-1 inhibitor on alcoholic gastritis. The TUNEL assay was used to determine DNA fragmentation. Results: Here, we clarified that ethanol treatment could cause cell DNA damage, activate caspase-1, and promote the generation and release of IL-1β and IL-18. In other words, ethanol could induce pyroptosis. Interestingly, a caspase-1 inhibitor could significantly suppress pyroptosis, decrease the release of inflammatory cytokines induced by ethanol, and cause no side effects in vivo and in vitro. Conclusion: Collectively, our results showed that pyroptosis is involved in the pathogenesis of alcohol-induced gastritis and that caspase-1 inhibitor Ac-yvad-cmk could effectively decrease the damage caused by alcohol, making it a potentially promising agent for the treatment of alcoholic gastritis.