PIAS1 inhibited the metastasis of gastric cancer cell by epithelial-mesenchymal transition regulation within the inflammatory microenvironment.

Protein inhibitor of activated signal transducer and activator of transcription-1 (PIAS1) is an important regulator of the inflammatory signaling network, the expression of which was decreased in gastric cancer and implicated in the development of cancer. However, its mechanism has not been elucidated. The aim of the present study was to investigate the effect of PIAS1 on epithelial-mesenchymal transition (EMT) of gastric cancer cells within the inflammatory microenvironment. Recombinant adenovirus Ad5/F35-PIASl and Ad5/F35-null plasmids were constructed to transfect SGC7901 cells. Subsequently, these plasmids were confirmed by reverse transcription polymerase chain reaction and western blotting. The cells were treated with IL-6 or Ad5/F35-PIASl+IL-6, and the control cells were treated with Ad5/F35-null+IL-6. The morphological changes to the cells were observed using inverted microscopy. The effect of PIAS1 on cell migration and invasion was evaluated by scratch wound healing and Transwell chamber assays, and the protein expression of EMT markers and phosphatidylinositol 3-kinase (PI3K)/serine/threonine-protein kinase (Akt)/matrix metalloproteinase (MMP)-9 signaling pathway was examined by western blotting. Transfection with Ad5/F35-PIASl markedly increased the PIAS1 expression in SGC7901 cells. The cells acquired the more typical spindle-shape phenotype of mesenchymal cells following co-culture with IL-6; the cells co-cultured with IL-6 and Ad5/F35-PIASl acquired changes concordant with an epithelial phenotype. The overexpression of PIAS1 significantly decreased the migratory and invasive capacities of the SGC7901 cells (P<0.01). Western blotting indicated that the expression levels of E-cadherin protein in the cells treated with Ad5/F35-PIASl+IL-6 were increased significantly and the expression levels of zinc finger protein SNAI, Twist-related protein 1, vimentin and MMP-9, and the activation of PI3K/Akt proteins were decreased when compared with IL-6- or Ad5/F35-null+IL-6-treated cells (both P<0.01). PIAS1 may inhibit EMT in gastric cancer cells within the inflammatory microenvironment via the regulation of PI3K/Akt pathway activation, and may serve an important role in the inhibition of tumor invasion and metastasis with in this microenvironment.