Involvement of H+-gradient dependent transporter in PGE2 release from A549 cells

Abstract

The purpose of this study was to identify the transporter involved in the release of prostaglandin E2 (PGE2). In the present study, transport assays were conducted using membrane vesicles prepared from human lung adenocarcinoma A549 cells, thus enabling identification of the novel exporter present in A549 cells. PGE2 transport into A549 vesicles was higher in the presence of a proton (H+)-gradient, thus suggesting the involvement of PGE2H+ symporter in PGE2 transport. Results from our experiments showed enhanced PGE2 release in A549 cells in the presence of H+-gradient ([H+]extracellular < [H+]intracellular). Moreover, in vesicular transport assays, H+-gradient-dependent transport of PGE2 did not show saturation up to 500 μM PGE2, and 10 mM aromatic monocarboxylic acids (acetylsalicylic acid, salicylic acid, and p-nitrobenzoic acid) significantly inhibited PGE2 transport by 62–70%. These results suggest, the involvement of monocarboxylate transporters in the H+-gradient-dependent PGE2 export.