Vascular endothelial growth inhibitor 174 and its functional domains inhibit epithelial-mesenchymal transition in renal cell carcinoma cells in vitro

The present study was carried out to investigate the effects of vascular endothelial growth inhibitor 174 (VEGI174) and its functional domains (V7 and V8) on epithelial-mesenchymal transition (EMT) in renal cell carcinoma (RCC) cells in vitro. The RCC cell lines A498 and 786-0 were used in this study. Based on our preliminary study, we selected full-length VEGI174 and its functional domains (V7 and V8) as the target genes in this study. Plasmids containing VEGI174, V7 or V8 transgenes were constructed and transfected into A498 and 786-0 cell lines. Cytological activity was tested during cell culture. Quantitative PCR and western blot analysis were performed to determine the expression levels of EMT markers (E-cadherin, vimentin, beta-catenin and Slug). Overexpression of VEGI174, V7 or V8 did not have a significant influence on cell viability (P>0.05). The mRNA level of E-cadherin was significantly upregulated, while that of vimentin was down-regulated in A498(VEGIexp), A498(V7exp), A498(V8exp), 786-O-VEGIexp, 786-O-V7exp and 786-O-V8exp cells compared with the cells containing the empty plasmid controls (P<0.05). The western blot results showed that changes in protein expression levels were consistent with the changes in mRNA expression. Both the mRNA and protein expression levels of beta-catenin and Slug were downregulated in the A498(VEGIexp), A498(V7exp), A498(V8exp), 786-O-VEGIexp 786-O-V7exp and 786-O-V8exp cells. In conclusion, overexpression of VEGI174, V7 or V8 inhibited EMT in A498 and 786-O cells. Notably, V7 and V8 are two effective functional domains of VEGI174 that have the potential to be studied for peptide synthesis and the treatment of RCC.