PKG II effectively reversed EGF-induced protein expression alterations in human gastric cancer cell lines

Epidermal growth factor receptor (EGFR) plays an important role in gastric cancer (GC) progression. Our previous data demonstrated that type II cGMP-dependent protein kinase (PKG II) could block the EGF-EGFR axis as well as down-stream signaling pathways, for example, MAPK, PI3K, and PLC in GC cells. However, the exact mechanisms of PKG II against cancer remain unclear. Therefore, the present work was to address the above question. Human GC cell line AGS was infected with adenoviral construct encoding cDNA of PKG II (Ad-PKG II) to up-regulate PKG II and then treated with 8-pCPT-cGMP. Two-dimensional electrophoresis (2-DE) was used to analyze the changes of protein expression in the cells. The results showed that 17 proteins had more than twofold changes in EGF-treated group compared with control. However, Ad-PKG II could effectively reversed the changes. Furthermore, far upstream element-binding protein 1 (FUBP1) and MarvelD3 were chosen and PKG II activation reversed EGF/EGFR-induced up-regulation of FUBP1 and downregulation of MarvelD3, respectively. MarvelD3 silence effectively abolished the inhibitory effect of PKG II on EGF-triggered migration. These data indicated that the inhibitory effect of PKG II partially was associated with MarvelD3.