Rabeprazole exhibits antiproliferative effects on human gastric cancer cell lines

Intracellular proton extrusion in gastric Cancer cells has been reported to promote Cancer cell survival under acidic conditions via hydrogen/potassium adenosine triphosphatase (H⁺/K⁺-ATPase). Rabeprazole is a frequently used second-generation Proton Pump Inhibitor (PPI) that irreversibly inactivates gastric H⁺/K⁺-ATPase. Therefore, we hypothesized that rabeprazole could reduce the viability of gastric Cancer cells. In the present study, four human gastric Cancer cell lines and one non-cancer gastric cell line were cultured. Cell viability, the α- and β-subunits of H⁺/K⁺-ATPase and cellular Apoptosis were analyzed by dye exclusion assay, reverse transcription-polymerase chain reaction and annexin V-fluorescein isothiocyanate/propidium iodide staining, respectively. The expression level of total extracellular signal-regulated protein kinase 1/2 (ERK 1/2) and phosphorylated-ERK protein was detected by western blot analysis. Gastric Cancer cell lines were more tolerant of the acidic culture media than non-cancer cells. Administration of rabeprazole led to a marked decrease in the viability of MKN-28 cells. Exposure to rabeprazole induced significant Apoptosis in AGS cells. Rabeprazole completely inhibited the phosphorylation of ERK 1/2 in the MKN-28 cells, whereas the same effect was not observed in either the KATO III or MKN-45 cells. The ERK 1/2 inhibitor, PD98059, attenuated the viability of the AGS cells. A similar antiproliferative effect was observed in the rabeprazole treatment group. In addition, PD98059 and rabeprazole were able to efficaciously inhibit the phosphorylation of ERK 1/2 in the gastric Cancer cells. Therefore, it was concluded that rabeprazole can attenuate the cell viability of human gastric Cancer cells through inactivation of the ERK1/2 signaling pathway. The results of the present study demonstrate that rabeprazole inhibits the viability of gastric Cancer cells in vitro and may serve as a novel antineoplastic agent.