Proton pump inhibitor pantoprazole abrogates adriamycin-resistant gastric cancer cell invasiveness via suppression of Akt/GSK-β/β-catenin signaling and epithelial-mesenchymal transition.

The effect of proton pump inhibitor (PPI) on cancer risk has received much attention recently. In this study, we investigated the mechanism underlying multidrug resistance and the effect of a PPI pantoprazole using an adriamycin-resistant gastric cancer cell model (SGC7901/ADR). Compared with the parental cell line, SGC7901/ADR cells showed reduced proliferation rate, but higher resistance to adriamycin under both anchorage-dependent and -independent conditions. Notably, SGC7901/ADR cells underwent epithelial to mesenchymal transition (EMT) and showed increased migrating and invading capabilities. At molecular level, SGC7901/ADR cells showed strong activation of Wnt/β-catenin signaling pathway compared with parental sensitive cells. Interestingly, we found that a PPI pantoprazole can effectively reverse the aggressiveness and EMT marker expression of SGC7901/ADR cells. Furthermore, pantoprazole treatment resulted in a profound reduction of both total and phosphorylated forms of Akt and GSK-3β, which in turn suppressed the adriamycin-induced Wnt/β-catenin signaling in SGC7901/ADR cells. Taken together, we demonstrate that the aggressive phenotype of adriamycin-resistant SGC7901/ADR cells is mediated by induction of EMT and activation of the canonical Wnt/β-catenin signaling pathway. And for the first time, we show that it is possible to suppress the invasiveness of SGC7901/ADR cells by pantoprazole which targets the EMT and Akt/GSK-3β/β-catenin signaling.