Apoptosis of <italic>Acanthamoeba castellanii</italic> Trophozoites Induced by Oleic Acid.

Abstract: <italic>Acanthamoeba</italic> spp. can be parasitic in certain situations and are responsible for serious human infections, including <italic>Acanthamoeba</italic> keratitis, granulomatous amoebic encephalitis, and cutaneous acanthamoebiasis. We analyzed the fatty acid composition of <italic>Acanthamoeba castellanii</italic> trophozoites and tested the inhibitory activity of the main fatty acids, oleic acid and arachidonic acid, in vitro. Oleic acid markedly inhibited the growth of <italic>A. castellanii</italic>, with trophozoite viability of 57.4% at a concentration of 200 μM. Caspase‐3 staining and annexin V assays showed that apoptotic death occurred in <italic>A. castellanii</italic> trophozoites. Quantitative PCR and dot blot analysis showed increased levels of metacaspase and interleukin‐1β converting enzyme, which is also an indication of apoptosis. In contrast, arachidonic acid showed negligible inhibition of growth of <italic>A. castellanii</italic> trophozoites. Stimulated expression of <italic>Atg3</italic>,<italic> Atg8</italic> and LC3A/B genes and monodansylcadaverine labeling suggested that oleic acid induces apoptosis by triggering autophagy of trophozoites. [ABSTRACT FROM AUTHOR]