Mevinolin (lovastatin) potentiates the antiproliferative effects of ketoconazole and terbinafine against Trypanosoma (Schizotrypanum) cruzi: in vitro and in vivo studies

Abstract

We have studied the antiproliferative effects of mevinolin (lovastatin), an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, on the protozoan parasite Trypanosoma (Schizotrypanum) cruzi and its ability to potentiate the action of specific ergosterol biosynthesis inhibitors, such as ketoconazole and terbinafine, both in vitro and in vivo. Against the epimastigote form in vitro, mevinolin produced a dose-dependent reduction of the growth rate up to 25 ,uM, but at 50 and 75 ,uM, complete growth arrest and cell lysis took place after 144 and 96 h, respectively. A systematic study of the effects of mevinolin combined with ketoconazole and terbinafine, which act at different points in the ergosterol biosynthesis pathway, on the proliferation of epimastigotes indicated a synergic action, as shown by concave isobolograms and fractional inhibitory concentration indexes ranging from 0.17 to 0.54. Analysis of the sterol composition and de novo sterol synthesis in control and treated cells by thin-layer and gas-liquid chromatographies showed that the antiproliferative effects of the drug alone and in combination were correlated with the depletion of the endogenous ergosterol pool and particularly with a critical (exogenous) cholesterol/endogenous 4-desmethyl sterol ratio in the cells. When we studied the effects of mevinolin on the amastigote form proliferating inside Vero cells in vitro, only very modest effects on the parasites were observed up to 0.75 ,M; above this concentration, significant deleterious effects on the host cells were found. However, when the same concentration of the drug was combined with ketoconazole, it was able to reduce by a factor of 10 the concentration of the azole required to eradicate the parasite (from 10 to 1 nM), again indicating a synergic action. On the other hand, a combination of mevinolin and terbinafine had only additive effects on amastigotes, but a ternary combination of mevinolin, ketoconazole, and terbinafine was again clearly synergistic. In vivo studies with a murine model of Chagas' disease showed that mevinolin can also potentiate the therapeutic effects of ketoconazole in this system; combined treatment with the two drugs at doses that alone offered only limited protection against the parasite was able to essentially eliminate circulating parasites and produce complete protection against death. These results confirm the synergic action against the proliferative stages of T. cruzi both in vitro and in vivo of combined ergosterol biosynthesis inhibitors that act at different points in the pathway and suggest that mevinolin combined with azoles, such as ketoconazole, can be used in the treatment of human Chagas' disease.

Short-term therapy with simvastatin reduces inflammatory mediators and heart inflammation during the acute phase of experimental Chagas disease

“…Unfortunately, mice do not survive well due to the alterations in the metabolic pathways that are a result of a persistent inflammatory response induced by specific strains of T. cruzi (Sánchez-Guillén et al 2006), which is a limitation of this experimental model. However, mortality in our experimental model of Chagas disease could be delayed if we initiated a statin plus an anti-T. cruzi drug chemotherapeutic strategy, as previously demonstrated by Urbina et al (1993). In this previous study, the authors indicated that lovastatin was able to potentiate the therapeutic effects of ketoconazole, an azolic anti-fungal drug.…”

“…In this previous study, the authors indicated that lovastatin was able to potentiate the therapeutic effects of ketoconazole, an azolic anti-fungal drug. Additionally, combination therapy with both drugs at doses that offered only limited protection against T. cruzi was able to eliminate the presence of circulating parasites and prevent mortality (Urbina et al 1993).…”

“…Investigations that have analysed the effect of statins on T. cruzi infection were only associated with chemotherapy or with the capacity of the drugs to block sterol (ergosterol) formation in parasites, thereby affecting parasitic growth or the capacity of the parasite to infect mammalian cells (Florin-Christensen et al 1990, Urbina et al 1993, Hankins et al 2005, Priotto et al 2009). Here, inflammatory cardiac disease in mice was analysed to measure the ability of simvastatin to reduce cholesterol in infected animals, to modulate the levels of systemic and cardiac pro-inflammatory cytokines (IFN-γ, TNF-α) and chemokines (CCL2/MCP-1 and CCL5/RANTES) and to alter the heart inflammatory process at the end of the acute phase of the disease.…”

Match-making for posaconazole through systems thinking

“…Clearly, sterol biosynthesis is of proven druggability and targeting multiple steps in the same pathway can potentiate antiparasitic activity. Lovastatin, a blockbuster used for hypercholesterolemia, enhanced the antiproliferative effects of ketoconazole and terbinafine against T. cruzi in vitro and in vivo [18]. Evidence from yeast points in the same direction because at least a dozen proteins interacting with Erg11 (Cyp51 ortholog in S. cerevisiae) can be found in the sterol metabolic pathway [19].…”

“…It could also be a drug that is not 100% cidal itself but shows synergistic interaction with posaconazole, such as amiodarone, amlodipine, or clemastine [46,47]. In addition, aiming to completely block sterol synthesis, the combination partner could be another sterol biosynthesis inhibitor [15,18]. Here, we propose as an additional strategy the partnership between posaconazole and sphingolipid inhibitors.…”