title: An Antifungal Benzimidazole Derivative Inhibits Ergosterol Biosynthesis and Reveals Novel Sterols.
abstract: Fungal infections are a leading cause of morbidity and death for hospitalized patients, mainly because they remain difficult to diagnose and to treat. Diseases range from widespread superficial infections such as vulvovaginal infections to life-threatening systemic candidiasis. For systemic mycoses, only a restricted arsenal of antifungal agents is available. Commonly used classes of antifungal compounds include azoles, polyenes, and echinocandins. Due to emerging resistance to standard therapies, significant side effects, and high costs for several antifungals, there is a need for new antifungals in the clinic. In order to expand the arsenal of compounds with antifungal activity, we previously screened a compound library using a cell-based screening assay. A set of novel benzimidazole derivatives, including (S)-2-(1-aminoisobutyl)-1-(3-chlorobenzyl)benzimidazole (EMC120B12), showed high antifungal activity against several species of pathogenic yeasts, including Candida glabrata and Candida krusei (species that are highly resistant to antifungals). In this study, comparative analysis of EMC120B12 versus fluconazole and nocodazole, using transcriptional profiling and sterol analysis, strongly suggested that EMC120B12 targets Erg11p in the ergosterol biosynthesis pathway and not microtubules, like other benzimidazoles. In addition to the marker sterol 14-methylergosta-8,24(28)-dien-3β,6α-diol, indicating Erg11p inhibition, related sterols that were hitherto unknown accumulated in the cells during EMC120B12 treatment. The novel sterols have a 3β,6α-diol structure. In addition to the identification of novel sterols, this is the first time that a benzimidazole structure has been shown to result in a block of the ergosterol pathway.
authors.affiliation: Universität Stuttgart, Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Stuttgart, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Keller
authors.affiliation: Department für Pharmazie-Zentrum für Pharmaforschung, Ludwig-Maximilians-Universität, Munich, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Müller
authors.affiliation: Universität Stuttgart, Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Stuttgart, Germany.
authors.forename: Isabel
authors.initials: I
authors.lastname: Engelhardt
authors.affiliation: Fraunhofer Institut für Grenzflächen- und Bioverfahrenstechnik, Stuttgart, Germany.
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Hiller
authors.affiliation: Universität Stuttgart, Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Stuttgart, Germany.
authors.forename: Karin
authors.initials: K
authors.lastname: Lemuth
authors.affiliation: EMC Microcollections GmbH, Tübingen, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Eickhoff
authors.affiliation: EMC Microcollections GmbH, Tübingen, Germany.
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Wiesmüller
authors.affiliation: Fraunhofer Institut für Grenzflächen- und Bioverfahrenstechnik, Stuttgart, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Burger-Kentischer
authors.affiliation: Department für Pharmazie-Zentrum für Pharmaforschung, Ludwig-Maximilians-Universität, Munich, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Bracher
authors.affiliation: Universität Stuttgart, Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Stuttgart, Germany Fraunhofer Institut für Grenzflächen- und Bioverfahrenstechnik, Stuttgart, Germany steffen.rupp@igb.fraunhofer.de.
authors.forename: Steffen
authors.initials: S
authors.lastname: Rupp
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D001562:Benzimidazoles / Q000737:chemistry / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D002176:Candida albicans / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D041221:Candida glabrata / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D004875:Ergosterol / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000302:isolation & purification; D015725:Fluconazole / Q000737:chemistry / Q000494:pharmacology*; D005656:Fungal Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D057166:High-Throughput Screening Assays; D015739:Nocodazole / Q000737:chemistry / Q000494:pharmacology*; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology; D058886:Sterol 14-Demethylase / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D001562:Benzimidazoles; D005656:Fungal Proteins; D054852:Small Molecule Libraries; C059675:14-methylergosta-8,24(28)-dien-3,6-diol; D015725:Fluconazole; D058886:Sterol 14-Demethylase; D015739:Nocodazole; D004875:Ergosterol