title: Identification and characterization of antifungal compounds using a Saccharomyces cerevisiae reporter bioassay.
abstract: 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.
authors.affiliation: The Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America.
authors.forename: Brad
authors.initials: B
authors.lastname: Tebbets
authors.forename: Douglas
authors.initials: D
authors.lastname: Stewart
authors.forename: Stephanie
authors.initials: S
authors.lastname: Lawry
authors.forename: Jeniel
authors.initials: J
authors.lastname: Nett
authors.forename: Andre
authors.initials: A
authors.lastname: Nantel
authors.forename: David
authors.initials: D
authors.lastname: Andes
authors.forename: Bruce S
authors.initials: BS
authors.lastname: Klein
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D001681:Biological Assay / Q000379:methods*; D002176:Candida albicans / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D025141:Drug Resistance, Fungal / Q000187:drug effects; D004357:Drug Synergism; D015725:Fluconazole / Q000494:pharmacology; D017930:Genes, Reporter / Q000235:genetics*; D000071677:Histidine Kinase; D008826:Microbial Sensitivity Tests; D020411:Oligonucleotide Array Sequence Analysis; D011494:Protein Kinases / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics* / Q000502:physiology
chemical_list: D000935:Antifungal Agents; D015725:Fluconazole; D011494:Protein Kinases; D000071677:Histidine Kinase