Miltefosine induces apoptosis in arsenite-resistant Leishmania donovani promastigotes through mitochondrial dysfunction.

The control of leishmaniasis in absence of vaccine solely depends on the choice of chemotherapy. The major hurdle in successful leishmanial chemotherapy is emergence of drug resistance. Miltefosine, the first orally administrable anti-leishmanial drug, has shown the potential against drug-resistant strains of Leishmania. However, there are discrepancies regarding the involvement of P-glycoprotein (Pgp) and sensitivity of miltefosine in multiple drug-resistant (MDR) cell lines that overexpress Pgp in Leishmania. To address this, the effect of miltefosine in arsenite-resistant Leishmania donovani (Ld-As20) promastigotes displaying an MDR phenotype and overexpressing Pgp-like protein was investigated in the current study. Results indicate that Ld-As20 is sensitive to miltefosine. Miltefosine induces process of programmed cell death in Ld-As20 in a time-dependent manner as determined by cell shrinkage, externalization of phosphatidylserine and DNA fragmentation. Miltefosine treatment leads to loss of mitochondrial membrane potential and the release of cytochrome C with consequent activation of cellular proteases. Activation of cellular proteases resulted in activation of DNase that damaged kinetoplast DNA and induced dyskinetoplasty. These data indicate that miltefosine causes apoptosis-like death in arsenite-resistant L. donovani.