Journal Article

Identification and characterization of antifungal compounds using a Saccharomyces cerevisiae reporter bioassay

Tebbets, Brad, Nett, Jeniel, Lawry, Stephanie, Klein, Bruce S, Stewart, Douglas, Andes, David, Nantel, Andre

2012

Overview

New antifungal drugs are urgently needed due to the currently limited selection, the emergence of drug resistance, and the toxicity of several commonly used drugs. To identify drug leads, we screened small molecules using a Saccharomyces cerevisiae reporter bioassay in which S. cerevisiae heterologously expresses Hik1, a group III hybrid histidine kinase (HHK) from Magnaporthe grisea. Group III HHKs are integral in fungal cell physiology, and highly conserved throughout this kingdom; they are absent in mammals, making them an attractive drug target. Our screen identified compounds 13 and 33, which showed robust activity against numerous fungal genera including Candida spp., Cryptococcus spp. and molds such as Aspergillus fumigatus and Rhizopus oryzae. Drug-resistant Candida albicans from patients were also highly susceptible to compounds 13 and 33. While the compounds do not act directly on HHKs, microarray analysis showed that compound 13 induced transcripts associated with oxidative stress, and compound 33, transcripts linked with heavy metal stress. Both compounds were highly active against C. albicans biofilm, in vitro and in vivo, and exerted synergy with fluconazole, which was inactive alone. Thus, we identified potent, broad-spectrum antifungal drug leads from a small molecule screen using a high-throughput, S. cerevisiae reporter bioassay.

• Publisher: PLOS,Public Library of Science,Public Library of Science (PLoS)
• Subject: amphotericin B / antifungal activity / antifungal agent / Antifungal agents / Antifungal Agents - pharmacology / antifungal resistance / Apoptosis / Aspergillus fumigatus / Aspergillus nidulans / bioassay / Bioassays / Biochemistry / Biocompatibility / biofilm / Biofilms / Biofilms - drug effects / Biological Assay / Biological Assay - methods / Biology / Cadmium / Cancer / Candida / Candida albicans / Candida albicans - drug effects / Candida albicans - genetics / Candida albicans - physiology / candidiasis / Carcinogens / colony forming unit / cortisone / Cryptococcus / Cryptococcus neoformans / Deoxyribonucleic acid / disk diffusion / DNA / DNA Damage / DNA microarray / DNA microarrays / DNA repair / DNA Repair - drug effects / down regulation / drug effect / Drug Evaluation, Preclinical / Drug Evaluation, Preclinical - methods / drug potency / drug potentiation / Drug resistance / Drug Resistance, Fungal / Drug Resistance, Fungal - drug effects / drug screening / drug structure / Drug Synergism / drug targeting / Drugs / Fluconazole / Fluconazole - pharmacology / fludioxonil / fungal strain / Fungi / Fungicides / fungus growth / Genes, Reporter - genetics / genetic transcription / Heavy metals / high throughput screening / Histidine / Histidine Kinase / Hybrids / Immunology / Journalists / Kinases / Magnaporthe grisea / Mammalia / Medical research / Medicine / microarray analysis / Microbial Sensitivity Tests / minimum inhibitory concentration / Molds / Molds (Fungi) / Oligonucleotide Array Sequence Analysis / Oxidative stress / Pediatrics / Phase transitions / protein expression / protein histidine kinase / protein kinase / Protein Kinases - genetics / Proteins / Public health / rat / reporter gene / Rhizopus oryzae / Saccharomyces cerevisiae / Saccharomyces cerevisiae - drug effects / Saccharomyces cerevisiae - genetics / Saccharomyces cerevisiae - physiology / Signal transduction / single drug dose / Stress response / Target recognition / Toxicity / Trends / upregulation / Yeast