The long-term goal of this project is to develop an effective therapy against relapsing vaginosis caused by Candida albicans. The disease occurs in 8-9% of all women, and is recalcitrant to currently available therapies. Upon adherence to a surface, C. albicans forms persister cells which are tolerant to currently available antimicrobials. Known compounds alone are inactive against persisters, so we reasoned that a combination of a compound disabling persister formation with a conventional antifungal will lead to eradication of the infection. To test this hypothesis, we developed a screen for potentiators of miconazole, a standard therapy against vaginosis. A pilot screen of 5,000 compounds produced an early lead, AC9 that completely eradicates populations of C. albicans containing persisters in combination with miconazole. AC9 or miconazole alone have no activity against persisters.
The Specific Aims of the project are: 1. In vitro validation of miconazole potentiators. The pilot screen of 5,000 compounds for potentiators of miconazole against C. albicans persister-producing biofilms gave 13 confirmed hits, of which 1, AC9, showed considerable microbicidal activity in combination with miconazole, but not alone. Additional hits will be obtained as described in Aim 2 below. The efficacy of potentiators in the presence of miconazole against a panel of C. albicans clinical isolates will be measured to determine MIC90 of the compound. Toxicity against human cells will be also examined. The probability of resistance development to the compound in the presence of miconazole will additionally be determined. Milestone: complete in vitro validation of AC9 and other lead compounds, which will indicate the feasibility of advancing these leads into animal studies at Phase II. 2. Identifying additional miconazole potentiators. a. Analogs of hit compounds. We will identify chemical analogs of AC9 and test them for potentiation of miconazole. Any compound with activity superior to AC9 will enter into validation. b. Screening for additional lead compounds. A compound library will be screened in a high-throughput format. As hits are identified, they, together with their available analogs, will enter the validation process described in Aim 1. Milestone: Identify ~10 potentiators of miconazole capable of eradicating a C. albicans biofilm and complete their in vitro validation. The proposed study will form the basis of a subsequent Phase II project, aimed at in vivo validation of the leads and their medicinal chemistry optimization. C. albicans is the major human fungal pathogen that forms essentially untreatable biofilm infections. This includes relapsing fungal vaginosis which afflicts 8-9% of all women and is recalcitrant to current therapies. This project will develop lead compounds that will form the basis for an effective therapeutic against vaginosis.
| Lafleur, Michael D; Sun, Lingmei; Lister, Ida et al. (2013) Potentiation of azole antifungals by 2-adamantanamine. Antimicrob Agents Chemother 57:3585-92 |
