Naphthoquinone derivatives exert their antitrypanosomal activity via a multi-target mechanism

• Published in: PLoS neglected tropical diseases Vol. 7; no. 1; p. e2012
• Main Authors: Pieretti, Simone, Haanstra, Jurgen R, Mazet, Muriel, Perozzo, Remo, Bergamini, Christian, Prati, Federica, Fato, Romana, Lenaz, Giorgio, Capranico, Giovanni, Brun, Reto, Bakker, Barbara M, Michels, Paul A M, Scapozza, Leonardo, Bolognesi, Maria Laura, Cavalli, Andrea
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.01.2013; Public Library of Science (PLoS)
• Subjects: Antiprotozoal Agents - pharmacology; Biology; Chemistry; Chemotherapy; Drug dosages; Enzyme Inhibitors - pharmacology; Enzymes; Glyceraldehyde-3-Phosphate Dehydrogenases - antagonists & inhibitors; Glyceraldehyde-3-Phosphate Dehydrogenases - isolation & purification; Glycerol Kinase - antagonists & inhibitors; Glycerol Kinase - isolation & purification; Health aspects; Infections; Inhibitory Concentration 50; Kinases; Mass Spectrometry; Naphthoquinones - pharmacology; Organic compounds; Prevention; Proteome - analysis; Proteomics; Protozoa; Protozoan Proteins - analysis; Reactive Oxygen Species - metabolism; Reactive Oxygen Species - toxicity; Tropical diseases; Trypanosoma; Trypanosoma brucei rhodesiense - chemistry; Trypanosoma brucei rhodesiense - drug effects; Vaccines; Antiprotozoal Agents; Enzyme Inhibitors; Glyceraldehyde-3-Phosphate Dehydrogenases; Reactive Oxygen Species; Mass Spectrometry; Naphthoquinones; Trypanosoma brucei rhodesiense; Inhibitory Concentration 50; Proteome; Protozoan Proteins; Glycerol Kinase
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0002012

Recently, we reported on a new class of naphthoquinone derivatives showing a promising anti-trypanosomatid profile in cell-based experiments. The lead of this series (B6, 2-phenoxy-1,4-naphthoquinone) showed an ED(50) of 80 nM against Trypanosoma brucei rhodesiense, and a selectivity index of 74 with respect to mammalian cells. A multitarget profile for this compound is easily conceivable, because quinones, as natural products, serve plants as potent defense chemicals with an intrinsic multifunctional mechanism of action. To disclose such a multitarget profile of B6, we exploited a chemical proteomics approach. A functionalized congener of B6 was immobilized on a solid matrix and used to isolate target proteins from Trypanosoma brucei lysates. Mass analysis delivered two enzymes, i.e. glycosomal glycerol kinase and glycosomal glyceraldehyde-3-phosphate dehydrogenase, as potential molecular targets for B6. Both enzymes were recombinantly expressed and purified, and used for chemical validation. Indeed, B6 was able to inhibit both enzymes with IC(50) values in the micromolar range. The multifunctional profile was further characterized in experiments using permeabilized Trypanosoma brucei cells and mitochondrial cell fractions. It turned out that B6 was also able to generate oxygen radicals, a mechanism that may additionally contribute to its observed potent trypanocidal activity. Overall, B6 showed a multitarget mechanism of action, which provides a molecular explanation of its promising anti-trypanosomatid activity. Furthermore, the forward chemical genetics approach here applied may be viable in the molecular characterization of novel multitarget ligands.