Na+-ATPase and protein kinase C are targets to 1-O-hexadecylphosphocoline (miltefosine) in Trypanosoma cruzi

Miltefosine has been shown to be a very active compound against Trypanosoma cruzi. Here, we evaluated the effects of miltefosine on the activity of the Na+-ATPase and protein kinase C (PKC) present in the plasma membrane of T. cruzi. Furosemide (2 mM), a specific inhibitor of Na+-ATPase, abolished the growth of T. cruzi showing a crucial role of this enzyme to parasite growth. Miltefosine inhibited the Na+-ATPase activity with IC50 = 18 ± 5 μg mL−1. This effect was shown to be reversible, dependent on the pH and Ca2+. The inhibition was not observed when the membranes were solubilized with 0.1% deoxycholate, suggesting that the interaction between the enzyme and membrane phospholipids might be important for the drug effect. Miltefosine also inhibited the parasite PKC activity, but through a Na+-ATPase-independent way. Altogether the results indicate that miltefosine inhibits T. cruzi growth through, at least in part, the inhibition of both Na+-ATPase and PKC activities.