Curcumin Modulates Efflux Mediated by Yeast ABC Multidrug Transporters and Is Synergistic with Antifungals

Abstract

Curcumin (CUR), a natural product of turmeric, from rhizomes of Curcuma longa, is a known agent of reversal of drug resistance phenotypes in cancer cells overexpressing ATP-binding cassette (ABC) transporters, viz., ABCB1, ABCG2, and ABCC1. In the present study, we evaluated whether CUR could also modulate multidrug transporters of yeasts that belong either to the ABC family or to the major facilitator superfamily (MFS). The effect of CUR on multidrug transporter proteins was demonstrated by examining rhodamine 6G (R6G) efflux in Saccharomyces cerevisiae cells overexpressing the Candida albicans ABC transporters Cdr1p and Cdr2p (CaCdr1p and CaCdr2p, respectively) and the MFS transporters CaMdr1p and S. cerevisiae Pdr5p. CUR decreased the extracellular concentration of R6G in ABC transporter-expressing cells but had no effect on methotrexate efflux mediated through the MFS transporter CaMdr1p. CUR competitively inhibited R6G efflux and the photolabeling of CaCdr1p by [ 125 I]iodoarylazidoprazosin, a drug analogue of the substrate prazosin (50% inhibitory concentration, 14.2 M). Notably, the mutant variants of CaCdr1p that displayed abrogated efflux of R6G also showed reduced modulation by CUR. Drug susceptibility testing of ABC proteinexpressing cells by spot assays and checkerboard tests revealed that CUR was selectively synergistic with drug substrates such as R6G, ketoconazole, itraconazole, and miconazole but not with fluconazole, voriconazole, anisomycin, cycloheximide, or FK520. Taken together, our results provide the first evidence that CUR modulates only ABC multidrug transporters and could be exploited in combination with certain conventional antifungal drugs to reverse multidrug resistance in Candida cells.

Reversing Antifungal Drug Resistance using Natural Plant Products

“…They have excellent antifungal properties with low MIC values and negligible cytotoxicity. Hoechst 33342 and R6G are two fluorescent dyes that accumulate into cells and are then pumped out by the ABC superfamily as they are substrates for these efflux pumps [16]. Our results demonstrated that the mean intracellular concentration of these dyes in various Candida spp exposed to thymol and carvacrol were significantly higher than in the untreated controls [17].…”

The ABCs of Candida albicans Multidrug Transporter Cdr1

“…We have shown earlier that a disulfiram drug (Antabuse) inhibits the oligomycin-sensitive ATPase activity of Cdr1p (57). In addition, the polyphenol curcumin and the quorum-sensing molecule farnesol act as modulators of Cdr1p (58,59). Notably, disulfiram, curcumin, and farnesol also potentiate antifungal activity and thus display synergy with certain antifungals.…”

Inhibition of Saccharomyces cerevisiae Pdr5p by a natural compound extracted from Brazilian Red Propolis

“…From those five compounds 1 showed a strong inhibition (Figure 1) of the enzymatic activity of the multidrug efflux transporter Pdr5p of S. cerevisiae. Its IC50 value was lower than those reported for other natural compounds such as enniatin (Ivnitski-Steele et al, 2009) or curcumin (Sharma et al, 2009) two well-known inhibitors of multidrug efflux transporters. BRP-1 was not toxic to the yeast cells used in this work even at high concentrations (50 µM).…”

“…This essay was performed as previously described by Sharma et al (2009) with slight modifications. Yeast cells in the logarithmic phase of growth were washed three times with phosphate-buffered saline (PBS) pH 7,0.…”