This study aims to investigate the significance of erythropoietin-producing hepatocellular (Eph)A2 expression and the mechanism by which EphA2 is involved in the epithelial-mensenchymal transition (EMT) of gastric cancer cells. EphA2 expression levels were upregulated and positively correlated with metastasis and EMT markers in human gastric cancer specimens. Modulation of EphA2 expression levels had distinct effects on cell proliferation, cell cycle, migration, invasion and morphology in the gastric cancer cell lines SGC7901 and AGS in vitro and in vivo. Overexpression of EphA2 resulted in the upregulation of the EMT molecular markers N-cadherin and Snail, as well as the Wnt/β-catenin targets TCF4, Cyclin-D1 and c-Myc, while silencing EphA2 using short hairpin RNA had the opposite effect. Furthermore, inhibition of the Wnt/β-catenin pathway by XAV939 negated the effect of EphA2 overexpression, whereas activation of the Wnt/β-catenin pathway by LiCl impaired the effect of the EphA2 knockdown on EMT. These observations demonstrate that EphA2 upregulation is a common event in gastric cancer specimens that is closely correlated with cancer metastasis and that EphA2 promotes EMT of gastric cancer cells through activation of Wnt/β-catenin signaling.

This study aims to investigate the expression and significance of glucose-6-phosphate dehydrogenase (G6PD) in human gastric cancer progression and prognosis. Using immunohistochemistry and real-time RT-PCR assay, we identified abnormally elevated expression of G6PD in gastric cancer tissues compared to paired normal stomach mucosa tissues in 24 patients (p < 0.05). In order to investigate the correlations between G6PD and the clinicopathological features of gastric cancer, the expression of G6PD in 167 patients with gastric cancer were detected by immunohistochemistry, and the results showed that overexpression of G6PD was associated with the size of tumor (p = 0.039), depth of invasion (p = 0.039), lymph node metastasis (p = 0.044), distant metastasis (p = 0.003), TNM stage (p = 0.030), and survival rate (p = 0.010). Further, Cox multivariates analysis indicated that G6PD expression level was an independent prognostic factor for patients after radical resection (p = 0.013). In conclusion, overexpression of G6PD is closely related to progression of gastric cancer, and might be regarded as an independent predictor of poor prognosis for gastric cancer.

Background: Liver metastasis of colon cancer is strongly affected by the tumor microenvironment (TME), with interactions between tumor cells and cancer-associated fibroblasts (CAFs) in particular. TGFβ is well known for its ability to mediate the CAF phenotype, and CXCR4 expression is closely correlated to poor prognosis in CRC. The relationship between these two signaling pathways remains to be delineated in liver metastasis of colon cancer. Methods: Immunohistochemistry was employed to investigate CXCR4 expression in 45 human specimens of primary colorectal cancer (CRC) and liver metastasis. The functions of SDF-1 released by hepatic stellate cells (HSCs) on CXCR4 and TGF-β1 in CRC cells were investigated in vitro. The effects of CRC on HSCs differentiation into CAFs were confirmed using co-culture technology and expression analysis of CAFs markers by qPCR, western blot and immunofluorescence. The involvement of CXCR4 and TGF-β1 was verified with addition of CXCR4 inhibitor AMD3100 and TGF-β1 inhibitor cyclophosphamide (Cy) both in vitro and in vivo. Results: There were more CXCR4-positive cells at the liver metastatic tissues compared to the primary sites. CRC cells activated and transformed HSCs to CAFs after co-cultivating with HSCs. Activated HSCs stimulated TGF-β1 secretion from CRC cells after co-culture with CRC cells in vitro. Moreover, the expression of CAFs markers was increasing in the activated HSCs. In a mouse hepatic metastasis model, treated with AMD3100 or Cy blocked the metastatic potential of HCT116 cells and the hepatic CAFs differentiation. Conclusions: These results indicated that CXCR4/TGF-β1 axis plays an important role in CRC liver metastasis through mediating HSCs differentiation into CAFs, providing preclinical evidences that blockade of the axis might be beneficial for anti-metastasis therapy in CRC.

The expression of EphA2 and three epithelial-mesenchymal transition-related proteins (E-cadherin, β-catenin and vimentin) was detected by immunohistochemistry in human gastric cancer and normal gastric mucosa. The expression of EphA2 and vimentin was significantly higher in gastric cancer tissues than in normal gastric mucosa tissues, and similar results were found for negative E-cadherin expression and ectopic β-catenin expression. Further analysis showed that the expression of EphA2 was closely correlated with the depth of tumor invasion, tumor-node-metastasis (TNM) stages and lymph node metastasis. Down-regulated expression of the epithelial protein E-cadherin, overexpression of the mesenchymal protein vimentin and ectopic expression of β-catenin were associated with the depth of tumor invasion, tumor differentiation, TNM stages and lymph node metastasis. The Spearman rank test indicated that the positive expression of EphA2 was negatively associated with E-cadherin expression and was positively correlated with β-catenin ectopic expression and vimentin expression. In addition, the Kaplan-Meier survival analysis showed that the overexpression of EphA2 and vimentin, ectopic expression of β-catenin and down-regulation of E-cadherin indicate a poor outcome. Moreover, multivariate Cox analysis showed that TNM stages, lymph node metastasis, EphA2 expression, E-cadherin expression and β-catenin ectopic expression were independent prognostic factors for postoperative gastric cancer. These findings indicate that the overexpression of EphA2 correlates with the loss of epithelial proteins and the appearance of mesenchymal proteins. Therefore, EphA2 may play a role in epithelial-mesenchymal transition in gastric cancer.