1
|
Chowdhury S, Nandi N. Computational study of the mechanism of binding of antifungal icofungipen in the active site of eukaryotic isoleucyl tRNA synthetase from Candida albicans. J Biomol Struct Dyn 2024:1-11. [PMID: 38444320 DOI: 10.1080/07391102.2024.2323143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 02/15/2024] [Indexed: 03/07/2024]
Abstract
The eukaryotic fungal species Candida albicans is a critical infective pathogenic agent. The β-amino acid, Icofungipen, is an effective inhibitor of Candida albicans. Icofungipen binds at the active site of the isoleucyl tRNA synthetase (IleRS) from Candida albicans (CaIleRS) and halts protein translation in fungus. In the present work, we have investigated the mechanism of binding of Icogungipen (abbreviated as IFP). Molecular dynamics (MD) simulations show that the carboxylic acid group of IFP in the CaIleRS: IFP complex is more oriented towards the Connective Polypeptide (CP) core loop compared to the carboxylic acid group of Ile in the CaIleRS: Ile complex. The Arg 410 of the CP core loop near the substrate is extended towards the IFP. Due to the difference in the conformation of residues of the CP core loop, the KMSKR loop is more proximal to the CP core loop in CaIleRS: IFP. The editing domain which is covalently linked with the CP core loop in the CaIleRS: IFP complex is also oriented in such a way that the active site cavity is narrow and longer. The metadynamics calculation shows that the IFP is trapped in a deeper potential well compared to Ile which is due to the effective closure of the gateway of the active site by KMSKR and CP core loop. The thin, long shape of the active site and the closed gate of the active site in CaIleRS: IFP complex is responsible for the effective capture of IFP relative to Ile in the active site.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Shilpi Chowdhury
- Department of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal, India
| | - Nilashis Nandi
- Department of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal, India
| |
Collapse
|
2
|
Abstract
Aminoacyl-tRNA synthetases (AARSs) have been considered very attractive drug-targets for decades. This interest probably emerged with the identification of differences in AARSs between prokaryotic and eukaryotic species, which provided a rationale for the development of antimicrobials targeting bacterial AARSs with minimal effect on the homologous human AARSs. Today we know that AARSs are not only attractive, but also valid drug targets as they are housekeeping proteins that: (i) play a fundamental role in protein translation by charging the corresponding amino acid to its cognate tRNA and preventing mistranslation mistakes [1], a critical process during fast growing conditions of microbes; and (ii) present significant differences between microbes and humans that can be used for drug development [2]. Together with the vast amount of available data on both pathogenic and mammalian AARSs, it is expected that, in the future, the numerous reported inhibitors of AARSs will provide the basis to develop new therapeutics for the treatment of human diseases. In this chapter, a detailed summary on the state-of-the-art in drug discovery and drug development for each aminoacyl-tRNA synthetase will be presented.
Collapse
Affiliation(s)
- Maria Lukarska
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Drug Targets in Human Diseases, INSERM U1209, CNRS UMR 5309, University Grenoble Alpes, Grenoble, France
| | - Andrés Palencia
- Institute for Advanced Biosciences (IAB), Structural Biology of Novel Drug Targets in Human Diseases, INSERM U1209, CNRS UMR 5309, University Grenoble Alpes, Grenoble, France.
| |
Collapse
|
3
|
Abstract
Aminoacyl-tRNA synthetases (ARSs) are essential enzymes for protein synthesis with evolutionarily conserved enzymatic mechanisms. Despite their similarity across organisms, scientists have been able to generate effective anti-infective agents based on the structural differences in the catalytic clefts of ARSs from pathogens and humans. However, recent genomic, proteomic and functionomic advances have unveiled unexpected disease-associated mutations and altered expression, secretion and interactions in human ARSs, revealing hidden biological functions beyond their catalytic roles in protein synthesis. These studies have also brought to light their potential as a rich and unexplored source for new therapeutic targets and agents through multiple avenues, including direct targeting of the catalytic sites, controlling disease-associated protein-protein interactions and developing novel biologics from the secreted ARS proteins or their parts. This Review addresses the emerging biology and therapeutic applications of human ARSs in diseases including autoimmune and rare diseases, and cancer.
Collapse
|
4
|
Amino Acid Metabolism and Transport Mechanisms as Potential Antifungal Targets. Int J Mol Sci 2018; 19:ijms19030909. [PMID: 29562716 PMCID: PMC5877770 DOI: 10.3390/ijms19030909] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 01/15/2023] Open
Abstract
Discovering new drugs for treatment of invasive fungal infections is an enduring challenge. There are only three major classes of antifungal agents, and no new class has been introduced into clinical practice in more than a decade. However, recent advances in our understanding of the fungal life cycle, functional genomics, proteomics, and gene mapping have enabled the identification of new drug targets to treat these potentially deadly infections. In this paper, we examine amino acid transport mechanisms and metabolism as potential drug targets to treat invasive fungal infections, including pathogenic yeasts, such as species of Candida and Cryptococcus, as well as molds, such as Aspergillus fumigatus. We also explore the mechanisms by which amino acids may be exploited to identify novel drug targets and review potential hurdles to bringing this approach into clinical practice.
Collapse
|
5
|
Liu N, Tu J, Dong G, Wang Y, Sheng C. Emerging New Targets for the Treatment of Resistant Fungal Infections. J Med Chem 2018; 61:5484-5511. [DOI: 10.1021/acs.jmedchem.7b01413] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Na Liu
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
| | - Jie Tu
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
| | - Guoqiang Dong
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
| | - Yan Wang
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
| | - Chunquan Sheng
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, People’s Republic of China
| |
Collapse
|
6
|
|
7
|
Abstract
Fungal organisms are ubiquitous in the environment. Pathogenic fungi, although relatively few in the whole gamut of microbial pathogens, are able to cause disease with varying degrees of severity in individuals with normal or impaired immunity. The disease state is an outcome of the fungal pathogen's interactions with the host immunity, and therefore, it stands to reason that deep/invasive fungal diseases be amenable to immunotherapy. Therefore, antifungal immunotherapy continues to be attractive as an adjunct to the currently available antifungal chemotherapy options for a number of reasons, including the fact that existing antifungal drugs, albeit largely effective, are not without limitations, and that morbidity and mortality associated with invasive mycoses are still unacceptably high. For several decades, intense basic research efforts have been directed at development of fungal immunotherapies. Nevertheless, this approach suffers from a severe bench-bedside disconnect owing to several reasons: the chemical and biological peculiarities of the fungal antigens, the complexities of host-pathogen interactions, an under-appreciation of the fungal disease landscape, the requirement of considerable financial investment to bring these therapies to clinical use, as well as practical problems associated with immunizations. In this general, non-exhaustive review, we summarize the features of ongoing research efforts directed towards devising safe and effective immunotherapeutic options for mycotic diseases, encompassing work on antifungal vaccines, adoptive cell transfers, cytokines, antimicrobial peptides (AMPs), monoclonal antibodies (mAbs), and other agents.
Collapse
Affiliation(s)
- Kausik Datta
- a Division of Infectious Diseases , Johns Hopkins University School of Medicine , Baltimore , MD , USA , and
| | - Mawieh Hamad
- b Department of Medical Laboratory Sciences and the Sharjah Institute for Medical Research , University of Sharjah , Sharjah , UAE
| |
Collapse
|
8
|
Prasad R, Shah AH, Rawal MK. Antifungals: Mechanism of Action and Drug Resistance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 892:327-349. [PMID: 26721281 DOI: 10.1007/978-3-319-25304-6_14] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
There are currently few antifungals in use which show efficacy against fungal diseases. These antifungals mostly target specific components of fungal plasma membrane or its biosynthetic pathways. However, more recent class of antifungals in use is echinocandins which target the fungal cell wall components. The availability of mostly fungistatic antifungals in clinical use, often led to the development of tolerance to these very drugs by the pathogenic fungal species. Thus, the development of clinical multidrug resistance (MDR) leads to higher tolerance to drugs and its emergence is helped by multiple mechanisms. MDR is indeed a multifactorial phenomenon wherein a resistant organism possesses several mechanisms which contribute to display reduced susceptibility to not only single drug in use but also show collateral resistance to several drugs. Considering the limited availability of antifungals in use and the emergence of MDR in fungal infections, there is a continuous need for the development of novel broad spectrum antifungal drugs with better efficacy. Here, we briefly present an overview of the current understanding of the antifungal drugs in use, their mechanism of action and the emerging possible novel antifungal drugs with great promise.
Collapse
Affiliation(s)
- Rajendra Prasad
- Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India. .,AMITY Institute of Integrative Sciences and Health (AIISH), Amity University Haryana, Manesar, Gurgaon, Haryana, India.
| | - Abdul Haseeb Shah
- Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Manpreet Kaur Rawal
- Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| |
Collapse
|
9
|
Berenji F, Zabolinejad N, Badiei Z, Kakhi S, Andalib Aliabadi Z, Ganjbakhsh M. Oropharyngeal candidiasis in children with lymphohematopoietic malignancies in Mashhad, Iran. Curr Med Mycol 2015; 1:33-36. [PMID: 28681002 PMCID: PMC5490279 DOI: 10.18869/acadpub.cmm.1.4.33] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background and Purpose: Over the past years, the role of fungi as a cause of nosocomial infections in hospitalized patients has been accentuated. Candida species constitute an important group of fungi causing diseases in immunocompromised patients. Oropharyngeal candidiasis continues to be a prevalent infection in immunodeficient patients. In this study, we aimed to determine the incidence of oropharyngeal candidiasis in children with lymphohematopoietic malignancies. Materials and Methods: In total, 102 patients with lymphohematopoietic malignancies and 50 healthy controls were examined in terms of Candida infections via direct sampling of the oropharyngeal cavity. Fresh smears were prepared with 10% potassium hydroxide and Gram staining was carried out. Subsequently, the obtained specimens were cultured on Sabouraud dextrose agar for further analysis. Results: The most common Candida species were Candida albicans (31%), other non-C. albicans species (14.7%), C. glabrata (6.8%), and C. krusei (0.98%) in the case group, while in the control group, other non-C. albicans species (10%) and C. albicans (8%) were the most common species. Conclusion: In the present study, Candida species were the most common fungal pathogens in pediatric cancer patients; therefore, efforts should be made to prevent fungemia and fungal pneumonia. Also, non-C. albicans species must be considered as a new risk factor for pediatric cancer patients.
Collapse
Affiliation(s)
- F Berenji
- Professor of Parasitology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - N Zabolinejad
- Associate Professor of Pathology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Z Badiei
- Associate Professor of Pediatric Hematology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - S Kakhi
- MD, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Z Andalib Aliabadi
- MSc of Parasitology School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - M Ganjbakhsh
- MSc Student of Mycology School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| |
Collapse
|
10
|
Genetic validation of aminoacyl-tRNA synthetases as drug targets in Trypanosoma brucei. EUKARYOTIC CELL 2014; 13:504-16. [PMID: 24562907 DOI: 10.1128/ec.00017-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Human African trypanosomiasis (HAT) is an important public health threat in sub-Saharan Africa. Current drugs are unsatisfactory, and new drugs are being sought. Few validated enzyme targets are available to support drug discovery efforts, so our goal was to obtain essentiality data on genes with proven utility as drug targets. Aminoacyl-tRNA synthetases (aaRSs) are known drug targets for bacterial and fungal pathogens and are required for protein synthesis. Here we survey the essentiality of eight Trypanosoma brucei aaRSs by RNA interference (RNAi) gene expression knockdown, covering an enzyme from each major aaRS class: valyl-tRNA synthetase (ValRS) (class Ia), tryptophanyl-tRNA synthetase (TrpRS-1) (class Ib), arginyl-tRNA synthetase (ArgRS) (class Ic), glutamyl-tRNA synthetase (GluRS) (class 1c), threonyl-tRNA synthetase (ThrRS) (class IIa), asparaginyl-tRNA synthetase (AsnRS) (class IIb), and phenylalanyl-tRNA synthetase (α and β) (PheRS) (class IIc). Knockdown of mRNA encoding these enzymes in T. brucei mammalian stage parasites showed that all were essential for parasite growth and survival in vitro. The reduced expression resulted in growth, morphological, cell cycle, and DNA content abnormalities. ThrRS was characterized in greater detail, showing that the purified recombinant enzyme displayed ThrRS activity and that the protein localized to both the cytosol and mitochondrion. Borrelidin, a known inhibitor of ThrRS, was an inhibitor of T. brucei ThrRS and showed antitrypanosomal activity. The data show that aaRSs are essential for T. brucei survival and are likely to be excellent targets for drug discovery efforts.
Collapse
|
11
|
Pitman SK, Drew RH, Perfect JR. Addressing current medical needs in invasive fungal infection prevention and treatment with new antifungal agents, strategies and formulations. Expert Opin Emerg Drugs 2011; 16:559-586. [DOI: 10.1517/14728214.2011.607811] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
12
|
Patočka J. β-AMINO ACIDS AND THEIR NATURAL BIOLOGICALLY ACTIVE DERIVATIVES. 5. DERIVATIVES OF UNUSUAL ALICYCLIC AND HETEROCYCLIC β-AMIMO ACIDS. ACTA ACUST UNITED AC 2011. [DOI: 10.31482/mmsl.2011.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
13
|
Zhou M, Dong X, Shen N, Zhong C, Ding J. Crystal structures of Saccharomyces cerevisiae tryptophanyl-tRNA synthetase: new insights into the mechanism of tryptophan activation and implications for anti-fungal drug design. Nucleic Acids Res 2010; 38:3399-413. [PMID: 20123733 PMCID: PMC2879500 DOI: 10.1093/nar/gkp1254] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Specific activation of amino acids by aminoacyl-tRNA synthetases is essential for maintaining translational fidelity. Here, we present crystal structures of Saccharomyces cerevisiae tryptophanyl-tRNA synthetase (sTrpRS) in apo form and in complexes with various ligands. In each complex, there is a sulfate ion bound at the active site which mimics the α- or β-phosphate group of ATP during tryptophan activation. In particular, in one monomer of the sTrpRS–TrpNH2O complex, the sulfate ion appears to capture a snapshot of the α-phosphate of ATP during its movement towards tryptophan. Simulation study of a human TrpRS–Trp–ATP model shows that during the catalytic process the α-phosphate of ATP is driven to an intermediate position equivalent to that of the sulfate ion, then moves further and eventually fluctuates at around 2 Å from the nucleophile. A conserved Arg may interact with the oxygen in the scissile bond at the transition state, indicating its critical role in the nucleophilic substitution. Taken together, eukaryotic TrpRSs may adopt an associative mechanism for tryptophan activation in contrast to a dissociative mechanism proposed for bacterial TrpRSs. In addition, structural analysis of the apo sTrpRS reveals a unique feature of fungal TrpRSs, which could be exploited in rational antifungal drug design.
Collapse
Affiliation(s)
- Minyun Zhou
- State Key Laboratory of Molecular Biology and Research Center for Structural Biology, Institute of Biochemistry and Cell Biology, Shanghai, Shanghai 200031, China
| | | | | | | | | |
Collapse
|
14
|
Hamad M. Antifungal Immunotherapy and Immunomodulation: A Double-hitter Approach to Deal with Invasive Fungal Infections. Scand J Immunol 2008; 67:533-43. [DOI: 10.1111/j.1365-3083.2008.02101.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
15
|
Torchala M, Hoffmann M. IA, database of known ligands of aminoacyl-tRNA synthetases. J Comput Aided Mol Des 2007; 21:523-5. [PMID: 17882381 DOI: 10.1007/s10822-007-9135-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 09/03/2007] [Indexed: 10/22/2022]
Abstract
The IA database contains 240 structures of known inhibitors of aminoacyl-tRNA synthetases. Structures can be downloaded in different file formats (mol, sdf, smile, png). The search engine offers possibility of searching for the ligands with a given functional group. Additionally, one can search for ligands that act on selected synthetases and from particular references. The data include information which synthetase a given ligand inhibits together with the inhibition constant (IC50) if known.
Collapse
|
16
|
Ochsner UA, Sun X, Jarvis T, Critchley I, Janjic N. Aminoacyl-tRNA synthetases: essential and still promising targets for new anti-infective agents. Expert Opin Investig Drugs 2007; 16:573-93. [PMID: 17461733 DOI: 10.1517/13543784.16.5.573] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The emergence of resistance to existing antibiotics demands the development of novel antimicrobial agents directed against novel targets. Historically, bacterial cell wall synthesis, protein, and DNA and RNA synthesis have been major targets of very successful classes of antibiotics such as beta-lactams, glycopeptides, macrolides, aminoglycosides, tetracyclines, rifampicins and quinolones. Recently, efforts have been made to develop novel agents against validated targets in these pathways but also against new, previously unexploited targets. The era of genomics has provided insights into novel targets in microbial pathogens. Among the less exploited--but still promising--targets is the family of 20 aminoacyl-tRNA synthetases (aaRSs), which are essential for protein synthesis. These targets have been validated in nature as aaRS inhibition has been shown as the specific mode of action for many natural antimicrobial agents synthesized by bacteria and fungi. Therefore, aaRSs have the potential to be targeted by novel agents either from synthetic or natural sources to yield specific and selective anti-infectives. Numerous high-throughput screening programs aimed at identifying aaRS inhibitors have been performed over the last 20 years. A large number of promising lead compounds have been identified but only a few agents have moved forward into clinical development. This review provides an update on the present strategies to develop novel aaRS inhibitors as anti-infective drugs.
Collapse
Affiliation(s)
- Urs A Ochsner
- Replidyne, Inc., 1450 Infinite Dr, Louisville, CO 80027, USA.
| | | | | | | | | |
Collapse
|
17
|
Abstract
Invasive fungal infections are important causes of morbidity and mortality in critically ill non neutropenic patients. For many years, amphotericin B and flucytosine have been the only available antifungal agents for invasive fungal infections. Fortunately, the antifungal armamentarium has increased during the past two decades with the addition of several new agents. In addition to itraconazole and fluconazole, lipid formulations of amphotericin B, voriconazole, and caspofungin have been recently licensed. These various antifungal agents differ in their pharmacokinetic and pharmacodynamic profile.
Collapse
Affiliation(s)
- Mercedes Catalán
- Servicio de Medicina Intensiva, Unidad Polivalente, Hospital Universitario 12 de Octubre, Avenida de Córdoba s/n, 28041 Madrid, Spain.
| | | |
Collapse
|
18
|
Alley MRK, Baker SJ, Beutner KR, Plattner J. Recent progress on the topical therapy of onychomycosis. Expert Opin Investig Drugs 2007; 16:157-67. [PMID: 17243936 DOI: 10.1517/13543784.16.2.157] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Onychomycosis is a fungal infection of the fingernails and toenails that results in thickening, discoloration, splitting of the nails and lifting of the nail from the nail bed. The disease is caused by dermatophytes and has a high incidence within the general population, especially among older individuals. Present treatment options include both oral and topical drugs, with oral therapies giving better outcomes; however, neither of these treatment options provides high cure rates that are durable. The difficulty in treating onychomycosis results from the deep-seated nature of the infection within the nail unit (nail plate, nail bed and surrounding tissue) and the inability of drugs to effectively reach all sites. Ongoing drug development activities have focused on novel delivery technologies to facilitate penetration of existing antifungal drugs through the nail plate and on the discovery of inherently penetrable antifungals. AN-2690 represents an oxaborole antifungal that is designed to penetrate the nail plate and is showing promising results in clinical trials.
Collapse
Affiliation(s)
- Michael R K Alley
- Anacor Pharmaceuticals, 1060 East Meadow Circle, Palo Alto, CA 94303, USA
| | | | | | | |
Collapse
|
19
|
Hasenoehrl A, Galic T, Ergovic G, Marsic N, Skerlev M, Mittendorf J, Geschke U, Schmidt A, Schoenfeld W. In vitro activity and in vivo efficacy of icofungipen (PLD-118), a novel oral antifungal agent, against the pathogenic yeast Candida albicans. Antimicrob Agents Chemother 2006; 50:3011-8. [PMID: 16940096 PMCID: PMC1563551 DOI: 10.1128/aac.00254-06] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Revised: 04/05/2006] [Accepted: 07/01/2006] [Indexed: 11/20/2022] Open
Abstract
Icofungipen (PLD-118) is the representative of a novel class of antifungals, beta amino acids, active against Candida species. It has been taken through phase II clinical trials. The compound actively accumulates in yeast, competitively inhibiting isoleucyl-tRNA synthetase and consequently disrupting protein biosynthesis. As a result, in vitro activity can be studied only in chemically defined growth media without free amino acids that would compete with the uptake of the compound. The MIC of icofungipen was reproducibly measured in a microdilution assay using yeast nitrogen base medium at pH 6 to 7 after 24 h of incubation at 30 to 37 degrees C using an inoculum of 50 to 100 CFU/well. The MICs for 69 Candida albicans strains ranged from 4 to 32 microg/ml. This modest in vitro activity contrasts with the strong in vivo efficacy in C. albicans infection. This was demonstrated in a lethal model of C. albicans infection in mice and rats in which icofungipen showed dose-dependent protection at oral doses of 10 to 20 mg/kg of body weight per day in mice and 2 to 10 mg/kg/day in rats. The in vivo efficacy was also demonstrated against C. albicans isolates with low susceptibility to fluconazole, indicating activity against azole-resistant strains. The efficacy of icofungipen in mice and rats was not influenced by concomitant administration of equimolar amounts of L-isoleucine, which was shown to antagonize its antifungal activity in vitro. Icofungipen shows nearly complete oral bioavailability in a variety of species, and its in vivo efficacy indicates its potential for the oral treatment of yeast infections.
Collapse
|
20
|
Hurdle JG, O'Neill AJ, Chopra I. Prospects for aminoacyl-tRNA synthetase inhibitors as new antimicrobial agents. Antimicrob Agents Chemother 2005; 49:4821-33. [PMID: 16304142 PMCID: PMC1315952 DOI: 10.1128/aac.49.12.4821-4833.2005] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Julian Gregston Hurdle
- Antimicrobial Research Centre and School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | | |
Collapse
|
21
|
|
22
|
Butler MS. Natural products to drugs: natural product derived compounds in clinical trials. Nat Prod Rep 2005; 22:162-95. [PMID: 15806196 DOI: 10.1039/b402985m] [Citation(s) in RCA: 337] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Natural product and natural product-derived compounds that are being evaluated in clinical trials or in registration (current 31 December 2004) have been reviewed. Natural product derived drugs launched in the United States of America, Europe and Japan since 1998 and new natural product templates discovered since 1990 are discussed.
Collapse
Affiliation(s)
- Mark S Butler
- MerLion Pharmaceuticals, 1 Science Park Road, The Capricorn #05-01, Singapore Science Park II, Singapore 117528.
| |
Collapse
|