Project description:Fungal infections have become a clinical challenge due to the emergence of drug-resistance of invasive fungi and a rapid increase of novel pathogens. The development of drug resistance has further restricted the use of antifungal agents. Therefore, there is anurgentneedto searchforalternativetreatmentoptions for Cryptococcus neoformans (C. neoformans). Disulfiram (DSF) has a high human safety profile and promising applications as an antiviral, antifungal, antiparasitic, and anticancer agent. In contrast, the effect of DSF on Cryptococcus has yet to be thoroughly researched. This study investigated the antifungal effect and mechanism of DSF againstC. neoformansto provide a new theoretical foundation for treating Cryptococcal infections. In vitro studies demonstrated that DSF inhibitedCryptococcusat minimum inhibitory concentrations (MICs) ranging from 1.0 to 8.0 μg/mL. Combined antifungal effects were also observed with 5-fluorocytosine, amphotericin B, terbinafine, or ketoconazole. In vivo, DSF exerted asignificantprotectiveeffectforGalleria mellonella infected with C. neoformans.Mechanistic investigations showed that DSF dose-dependently inhibited the melanin, urease, acetaldehyde dehydrogenase, capsule, and biofilm formation or viability ofC. neoformans.Further study indicated DSF affectedC. neoformansby interfering with multiple biological pathways, including replication, metabolism, membrane transport, and biological enzyme activity. Potentially essential targets of these pathways included acetaldehyde dehydrogenase, catalase, ATP-binding cassette transporter (ABC transporter) AFR2, and iron-sulfur cluster transporter ATM1. These findings contribute to the understanding of mechanisms inC. neoformans, and provide new insights for the application of DSF.
Project description: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 reporter bioassay in which the yeast 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, Cryptococcus and molds such as Aspergillus and Rhizopus. Drug-resistant Candida 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 Candida 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, yeast reporter bioassay. Two-color experimental design testing the effects of 2 antifungal compounds (13 and 33) after 0, 20, 40 60 min. In the referred publication, the t=20, 40, 60 data was normalized against the t=0 data
Project description:Invasive fungal infections (IFIs) are difficult to treat. Few effective antifungal drugs are available and many have problems with toxicity, efficacy and drug-resistance. To overcome these challenges, existing therapies may be enhanced using more than one agent acting in synergy. Previously, we have found amphotericin B (AMB) and the iron chelator, lactoferrin (LF), were synergistic against Cryptococcus neoformans and Saccharomyces cerevisiae. This study investigates the mechanism of AMB+LF synergy using RNA-seq in Cryptococcus neoformans H99.
Project description: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 reporter bioassay in which the yeast 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, Cryptococcus and molds such as Aspergillus and Rhizopus. Drug-resistant Candida 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 Candida 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, yeast reporter bioassay.
Project description:Following antifungal treatment, Candida albicans, and other human pathogenic fungi can undergo microevolution, which leads to the emergence of drug resistance. However, the capacity for microevolutionary adaptation of fungi goes beyond the development of drug resistance. Here we used an experimental microevolution approach to show that one of the central pathogenicity mechanisms of C. albicans, the yeast-to-hyphae transition, can be subject to experimental evolution. The C. albicans cph1?/efg1? mutant is non-filamentous, as central signalling pathways linking environmental cues to hypha formation are disrupted. We subjected this mutant to constant selection pressure in the hostile environment of the macrophage phagosome. In a comparatively short time-frame, the mutant evolved the ability to escape macrophages by filamentation. To investigate the transcriptional response underlying the yeast-to-filament transition in the evolved strain, we applied RNA-Seq technology. Furthermore, RNA-Seq data were used to identify SNPs, which are specific for the evolved strain. For both strains, the cph1?/efg1? mutant and the Evo-strain, two conditions, one promotes yeast growth the other filamentous growth, were investigated. For each condition three biological replicates were analysed.
Project description:Two mutant strains of Aspergillus fumigatus derived from strain A1160, HapB and 29.9, display resistance to the antifungal drug itraconazole. To understand what underlying transcriptional processes contribute to this resistance, A1160, HapB and 29.9 were cultured either in the presence or absence of itraconazole. RNA-sequencing was used to compare transcription profiles of each mutant strain with or without the drug, to A1160 with or without drug.
Project description:The clinical response to chemotherapy regimen of cisplatin and paclitaxel in lung adenocarcinoma is frequently limited in magnitude and duration due to drug resistance. Recently, epithelial-mesenchymal transition (EMT) was associated with drug resistance. However, the underlying mechanisms remain elusive. To discover mechanisms of resistance, we developed the epithelial-like and mesenchymal-like A549 cell lines (lung adenocarcinoma cell line), and have their lncRNA expressions profiled and compared. Results provide insight into the molecular mechanisms underlying chemotherapy-resistance.
Project description:Following antifungal treatment, Candida albicans, and other human pathogenic fungi can undergo microevolution, which leads to the emergence of drug resistance. However, the capacity for microevolutionary adaptation of fungi goes beyond the development of drug resistance. Here we used an experimental microevolution approach to show that one of the central pathogenicity mechanisms of C. albicans, the yeast-to-hyphae transition, can be subject to experimental evolution. The C. albicans cph1Δ/efg1Δ mutant is non-filamentous, as central signalling pathways linking environmental cues to hypha formation are disrupted. We subjected this mutant to constant selection pressure in the hostile environment of the macrophage phagosome. In a comparatively short time-frame, the mutant evolved the ability to escape macrophages by filamentation. To investigate the transcriptional response underlying the yeast-to-filament transition in the evolved strain, we applied RNA-Seq technology. Furthermore, RNA-Seq data were used to identify SNPs, which are specific for the evolved strain.
Project description:The clinical efficacy of EGFR kinase inhibitors gefitinib and erlotinib is limited by the development of drug resistance. The most common mechanism of drug resistance is the secondary EGFR T790M mutation. Strategies to overcome EGFR T790M mediated drug resistance include the use of mutant selective EGFR inhibitors, including WZ4002, or by the use of high concentrations of irreversible quinazoline EGFR inhibitors such as PF299804. In the current study we develop drug resistant versions of the EGFR mutant PC9 cell line which reproducibly develops EGFR T790M as a mechanism of drug resistance to gefitinib. Neither PF299804 resistant (PFR) or WZ4002 resistant (WZR) clones of PC9 harbor EGFR T790M. Instead, they demonstrate activated IGF1R signaling as a result of loss of expression of IGFBP3 and the IGF1R inhibitor, BMS 536924, restores EGFR inhibitor sensitivity. Intriguingly, prolonged exposure to either PF299804 or WZ4002 results in the emergence of a more drug resistant subclone which contains ERK activation. A MEK inhibitor, CI-1040, partially restores sensitivity to EGFR/IGF1R inhibitor combination. Moreover, an IGF1R or MEK inhibitor used in combination with either PF299804 or WZ4002 completely prevents the emergence of drug resistant clones in this model system. Our studies suggest that more effective means of inhibiting EGFR T790M will prevent the emergence of this common drug resistance mechanism in EGFR mutant NSCLC. However, multiple drug resistance mechanisms can still emerge. Preventing the emergence of drug resistance, by targeting pathways activated in resistant cancers before they emerge, may be a more effective clinical strategy. Total of three samples with duplicate or triplicate each were analyzed.