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Updated: Jun 4, 2026
Small-Scale Plasma Membrane Preparation for the Analysis of Candida albicans Cdr1-mGFPHis
Published on: June 13, 2021
Identification of efflux inhibitors through a drug repurposing strategy in Candida albicans
Débora Marques1, Sofia Santos Costa1, Liliana Rodrigues1
1Global Health and Tropical Medicine, GHTM, LA-REAL, Instituto de Higiene e Medicina Tropical, IHMT, Universidade NOVA de Lisboa, Lisboa, Portugal.
Introduction:
Candida albicans is a major cause of nosocomial fungal infections, often associated with high morbidity and mortality. The rising resistance to antifungal drugs, particularly azoles, underscores the need for new therapeutic strategies. Among resistance mechanisms, alterations in drug targets and overexpression of efflux pump genes play key roles. Efflux inhibitors can enhance the intracellular drug accumulation, thereby restoring antifungal efficacy and preventing resistance development. Drug repurposing offers a cost-effective and time-efficient alternative for identifying new drugs, including efflux inhibitors. In this study, we used an in silico drug repurposing approach to identify approved drugs associated with membrane transport functions and evaluate their efflux-modulating potential in vitro.
Methods:
Using the DrugBank database, we screened predicted membrane transport proteins in C. albicans and selected those with homology to known drug targets. A subset of drugs, representative of each chemical group, was selected for in vitro screening against the reference strain C. albicans ATCC 90028. We further evaluated the potential adjuvant effect of these drugs on the activity of fluconazole. Finally, the efflux inhibitory effect of the candidate drugs was assessed by real-time fluorometric detection of ethidium bromide accumulation.
Results:
A total of 245 predicted membrane transport proteins were screened, 51 of which showed homology to known drug targets and were associated with 777 drugs. A subset of 59 drugs was selected for screening. The drug miltefosine showed the lowest minimum inhibitory concentration (MIC; 2 mg/L), while amlodipine and procainamide demonstrated an adjuvant effect by decreasing the MIC of fluconazole by at least four-fold. Fluorometric assays revealed amlodipine, fluvoxamine and fluoxetine as potential efflux inhibitors in C. albicans.
Discussion:
These findings highlight the potential of these drugs to contribute to the research and development of new therapeutic alternatives aimed at combating antifungal resistance.
Insights
This study repurposed existing drugs to combat antifungal resistance in Candida albicans. Amlodipine, fluvoxamine, and fluoxetine showed potential as efflux inhibitors, offering new therapeutic avenues.
Area of Science:
- Mycology and Infectious Diseases
- Pharmacology and Drug Discovery
- Computational Biology and Bioinformatics
Background:
- Candida albicans causes significant nosocomial infections with rising antifungal drug resistance.
- Efflux pump gene overexpression is a key mechanism of antifungal resistance.
- New therapeutic strategies are urgently needed to overcome drug resistance.
Purpose of the Study:
- To identify approved drugs with efflux-modulating potential against Candida albicans using an in silico drug repurposing approach.
- To evaluate the in vitro efficacy and adjuvant effects of identified drugs in combination with fluconazole.
- To assess the efflux inhibitory effects of candidate drugs.
Main Methods:
- Screened 245 predicted membrane transport proteins in Candida albicans for homology to known drug targets.
- Selected 59 drugs for in vitro screening against Candida albicans ATCC 90028.
- Assessed drug adjuvant effects on fluconazole activity and efflux inhibition using ethidium bromide accumulation assays.
Main Results:
- Miltefosine exhibited the lowest minimum inhibitory concentration (MIC) at 2 mg/L.
- Amlodipine and procainamide showed a four-fold decrease in fluconazole MIC, indicating an adjuvant effect.
- Amlodipine, fluvoxamine, and fluoxetine were identified as potential efflux inhibitors in Candida albicans.
Conclusions:
- Repurposing approved drugs can identify novel agents to combat antifungal resistance.
- Amlodipine, fluvoxamine, and fluoxetine show promise as efflux inhibitors for Candida albicans.
- These findings support the development of new therapeutic alternatives against resistant fungal infections.
