ABSTRACTAcanthamoeba
sp. parasites are the causative agents of
Acanthamoeba
keratitis, fatal granulomatous amoebic encephalitis, and cutaneous infections. However, there are currently no effective drugs for these organisms. Here, we evaluated the activity of the antimalarial agent artemether against
Acanthamoeba castellanii
trophozoites and identified potential targets of this agent through a proteomic approach. Artemether exhibited
in vitro
amoebicidal activity in a time- and dose-dependent manner and induced ultrastructural modification and cell apoptosis. The iTRAQ quantitative proteomic analysis identified 707 proteins that were differentially expressed after artemether treatment. We focused on phosphoglycerate dehydrogenase and phosphoserine aminotransferase in the serine biosynthesis pathway because of their importance to the growth and proliferation of protozoan and cancer cells. The expression of these proteins in
Acanthamoeba
was validated using quantitative real-time PCR and Western blotting after artemether treatment. The changes in the expression levels of phosphoserine aminotransferase were consistent with those of phosphoglycerate dehydrogenase. Therefore, the downregulation of phosphoserine aminotransferase may be due to the downregulation of phosphoglycerate dehydrogenase. Furthermore, exogenous serine might antagonize the activity of artemether against
Acanthamoeba
trophozoites. These results indicate that the serine biosynthesis pathway is important to amoeba survival and that targeting these enzymes would improve the treatment of
Acanthamoeba
infections. Artemether may be used as a phosphoglycerate dehydrogenase inhibitor to control or block
Acanthamoeba
infections.