Defeating Leishmania resistance to Miltefosine (hexadecylphosphocholine) by peptide-mediated drug smuggling: A proof of mechanism for trypanosomatid chemotherapy

Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain.
Journal of Controlled Release (Impact Factor: 7.71). 05/2012; 161(3):835-42. DOI: 10.1016/j.jconrel.2012.05.023
Source: PubMed


Miltefosine (hexadecylphosphocholine, HePC), the first orally active drug successful against leishmaniasis, is especially active on the visceral form of the disease. Resistance mechanisms are almost exclusively associated to dysfunction in HePC uptake systems. In order to evade the requirements of its cognate receptor/translocator, HePC-resistant Leishmania donovani parasites (R40 strain) were challenged with constructs consisting of an ω-thiol-functionalized HePC analogue conjugated to the cell-penetrating peptide (CPP) Tat(48-60), either through a disulfide or a thioether bond. The conjugates enter and kill both promastigote and intracellular amastigote forms of the R40 strain. Intracellular release of HePC by reduction of the disulfide-based conjugate was confirmed by means of double tagging at both the CPP (Quasar 670) and HePC (BODIPY) moieties. Scission of the conjugate, however, is not mandatory, as the metabolically more stable thioether conjugate retained substantial activity. The disulfide conjugate is highly active on the bloodstream form of Trypanosoma b. brucei, naturally resistant to HePC. Our results provide proof-of-mechanism for the use of CPP conjugates to avert drug resistance by faulty drug accumulation in parasites, as well as the possibility to extend chemotherapy into other parasites intrinsically devoid of membrane translocation systems.

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    • "Due to their translocating properties, they were named cell-penetrating peptides (CPPs) more than two decades ago [1] [2] [3] [4]. CPPs can be covalently conjugated or complexed with a variety of payloads, such as nucleic acids, proteins, nanoparticles or quantum dots [5] [6] [7], enabling their use in a broad range of applications, including transfection, siRNA technology, organelle imaging or delivery of low-permeability drugs [8] [9] [10]. The most studied CPPs in terms of cell translocation and effectiveness as biomedical agents are the HIV-1 transcriptional activator (Tat) [1], the antennapedia homeodomain from Drosophila (Antp) [11], and the VP22 protein from the Herpes simplex virus [12]. "
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