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Tang M, Zhao D, Liu S, Zhang X, Yao Z, Chen H, Zhou C, Zhou T, Xu C. The Properties of Linezolid, Rifampicin, and Vancomycin, as Well as the Mechanism of Action of Pentamidine, Determine Their Synergy against Gram-Negative Bacteria. Int J Mol Sci 2023; 24:13812. [PMID: 37762115 PMCID: PMC10530309 DOI: 10.3390/ijms241813812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/02/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Combining pentamidine with Gram-positive-targeting antibiotics has been proven to be a promising strategy for treating infections from Gram-negative bacteria (GNB). However, which antibiotics pentamidine can and cannot synergize with and the reasons for the differences are unclear. This study aimed to identify the possible mechanisms for the differences in the synergy of pentamidine with rifampicin, linezolid, tetracycline, erythromycin, and vancomycin against GNB. Checkerboard assays were used to detect the synergy of pentamidine and the different antibiotics. To determine the mechanism of pentamidine, fluorescent labeling assays were used to measure membrane permeability, membrane potential, efflux pump activity, and reactive oxygen species (ROS); the LPS neutralization assay was used to evaluate the target site; and quantitative PCR was used to measure changes in efflux pump gene expression. Our results revealed that pentamidine strongly synergized with rifampicin, linezolid, and tetracycline and moderately synergized with erythromycin, but did not synergize with vancomycin against E. coli, K. pneumoniae, E. cloacae, and A. baumannii. Pentamidine increased the outer membrane permeability but did not demolish the outer and inner membranes, which exclusively permits the passage of hydrophobic, small-molecule antibiotics while hindering the entry of hydrophilic, large-molecule vancomycin. It dissipated the membrane proton motive force and inactivated the efflux pump, allowing the intracellular accumulation of antimicrobials that function as substrates of the efflux pump, such as linezolid. These processes resulted in metabolic perturbation and ROS production which ultimately was able to destroy the bacteria. These mechanisms of action of pentamidine on GNB indicate that it is prone to potentiating hydrophobic, small-molecule antibiotics, such as rifampicin, linezolid, and tetracycline, but not hydrophilic, large-molecule antibiotics like vancomycin against GNB. Collectively, our results highlight the importance of the physicochemical properties of antibiotics and the specific mechanisms of action of pentamidine for the synergy of pentamidine-antibiotic combinations. Pentamidine engages in various pathways in its interactions with GNB, but these mechanisms determine its specific synergistic effects with certain antibiotics against GNB. Pentamidine is a promising adjuvant, and we can optimize drug compatibility by considering its functional mechanisms.
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Affiliation(s)
- Miran Tang
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325035, China; (M.T.); (S.L.); (X.Z.); (Z.Y.); (H.C.); (C.Z.)
| | - Deyi Zhao
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou 325015, China;
| | - Sichen Liu
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325035, China; (M.T.); (S.L.); (X.Z.); (Z.Y.); (H.C.); (C.Z.)
| | - Xiaotuan Zhang
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325035, China; (M.T.); (S.L.); (X.Z.); (Z.Y.); (H.C.); (C.Z.)
| | - Zhuocheng Yao
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325035, China; (M.T.); (S.L.); (X.Z.); (Z.Y.); (H.C.); (C.Z.)
| | - Hule Chen
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325035, China; (M.T.); (S.L.); (X.Z.); (Z.Y.); (H.C.); (C.Z.)
| | - Cui Zhou
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325035, China; (M.T.); (S.L.); (X.Z.); (Z.Y.); (H.C.); (C.Z.)
| | - Tieli Zhou
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325035, China; (M.T.); (S.L.); (X.Z.); (Z.Y.); (H.C.); (C.Z.)
| | - Chunquan Xu
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325035, China; (M.T.); (S.L.); (X.Z.); (Z.Y.); (H.C.); (C.Z.)
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Tang M, Qian C, Zhang X, Liu Y, Pan W, Yao Z, Zeng W, Xu C, Zhou T. When Combined with Pentamidine, Originally Ineffective Linezolid Becomes Active in Carbapenem-Resistant Enterobacteriaceae. Microbiol Spectr 2023; 11:e0313822. [PMID: 37125928 PMCID: PMC10269503 DOI: 10.1128/spectrum.03138-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 04/11/2023] [Indexed: 05/02/2023] Open
Abstract
The increasing prevalence of carbapenem-resistant Enterobacteriaceae (CRE) and their biofilm-relevant infections pose a threat to public health. The drug combination strategy provides a new treatment option for CRE infections. This study explored the synergistic antibacterial, antibiofilm activities as well as the in vivo efficacy against CRE of pentamidine combined with linezolid. This study further revealed the possible mechanisms underlying the synergy of the combination. The checkerboard and time-kill assays showed that pentamidine combined with linezolid had significant synergistic antibacterial effects against CRE strains (9/10). Toxicity assays on mammal cells (mouse RAW264.7 and red blood cells) and on Galleria mellonella confirmed that the concentrations of pentamidine and/or linezolid that were used were relatively safe. Antibiofilm activity detection via crystal violet staining, viable bacteria counts, and scanning electron microscopy demonstrated that the combination enhanced the inhibition of biofilm formation and the elimination of established biofilms. The G. mellonella infection model and mouse thigh infection model demonstrated the potential in vivo efficacy of the combination. In particular, a series of mechanistic experiments elucidated the possible mechanisms for the synergy in which pentamidine disrupts the outer membranes, dissipates the membrane potentials, and devitalizes the efflux pumps of CRE, thereby facilitating the intracellular accumulation of linezolid and reactive oxygen species (ROS), which ultimately kills the bacteria. Taken together, when combined with pentamidine, which acts as an outer membrane permeabilizer and as an efflux pump inhibitor, originally ineffective linezolid becomes active in CRE and exhibits excellent synergistic antibacterial and antibiofilm effects as well as a potential therapeutic effect in vivo on CRE-relevant infections. IMPORTANCE The multidrug resistance and biofilm formation of Gram-negative bacteria (GNB) may lead to incurable "superbug" infections. Drug combinations, with the potential to augment the original treatment ranges of drugs, are alternative treatment strategies against GNB. In this study, the pentamidine-linezolid combination showed notable antibacterial and antibiofilm activity both in vitro and in vivo against the problem carbapenem-resistant Enterobacteriaceae (CRE). Pentamidine is often used as an antiprotozoal and antifungal agent, and linezolid is a defensive Gram-positive bacteria (GPB) antimicrobial. Their combination expands the treatment range to GNB. Hence, the pentamidine-linezolid pair may be an effective treatment for complex infections that are mixed by GPB, GNB, and even fungi. In terms of mechanism, pentamidine inhibited the outer membranes, membrane potentials, and efflux pumps of CRE. This might be a universal mechanism by which pentamidine, as an adjuvant, potentiates other drugs, similar to linezolid, thereby having synergistic antibacterial effects on CRE.
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Affiliation(s)
- Miran Tang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, China
| | - Changrui Qian
- School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Xiaotuan Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, China
| | - Yan Liu
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, China
| | - Wei Pan
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, China
| | - Zhuocheng Yao
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Weiliang Zeng
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, China
| | - Chunquan Xu
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, China
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, China
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Khan RU, Khan M, Sohail A, Ullah R, Iqbal A, Ahmad B, Khan IU, Tariq A, Ahmad M, Said A, Ullah S, Ali A, Rahman MU, Zaman A, Bilal H. Efficacy of pentamidine-loaded chitosan nanoparticles as a novel drug delivery system for Leishmania tropica. Trop Biomed 2022; 39:511-517. [PMID: 36602209 DOI: 10.47665/tb.39.4.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The present study compares the in vitro effects of nanoparticles loaded pentamidine drug and conventional pentamidine on Leishmania tropica. Herein, pentamidine-loaded chitosan nanoparticles (PTN-CNPs) have been synthesized through an ionic gelation method with sodium tripolyphosphate (TPP). Next, the physical characteristics of PTN-CNPs were determined through the surface texture, zeta potential, in vitro drug release, drug loading content (DLC), and encapsulation efficacy (EE) and compared its efficacy with free pentamidine (PTN) drug against promastigotes and axenic amastigotes forms of L. tropica in vitro. The PTN-CNPs displayed a spherical shape having a size of 88 nm, an almost negative surface charge (-3.09 mV), EE for PTN entrapment of 86%, and in vitro drug release of 92% after 36 h. In vitro antileishmanial activity of PTN-CNPs and free PTN was performed against Leishmania tropica KWH23 promastigote and axenic amastigote using 3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphenyletetrazolium bromide (MTT) assay. It was observed that the effect of PTN-CNPs and free PTN on both forms of the parasite was dose and time dependent. Free PTN presented low efficacy even at higher dose (40 µg/ml) with 25.6 ± 1.3 and 26.5 ±1.4 mean viability rate of the promastigotes and axenic amastigotes, respectively after 72 hrs incubation. While PTN-CNPs showed strong antileishmanial effects on both forms of parasite with 16 ± 0.4 and 19 ± 0.7 mean viability rate at the same higher concentration (40 µg/ml) after 72 hrs incubation. Half maximal inhibitory concentration (IC50) values of PTN-CNPs toward promastigotes and amastigotes were obtained as 0.1375 µg/ml and 0.1910 µg/ml, respectively. In conclusion, PTN-CNPs effectively inhibited both forms of the L. tropica; however, its effect was more salient on promastigotes. This data indicates that the PTN-CNPs act as a target drug delivery system. However, further research is needed to support its efficacy in animal and human CL.
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Affiliation(s)
- R U Khan
- Institute of Pathology and Diagnostic Medicine, Khyber Medical University, Peshawar, Pakistan
| | - M Khan
- Institute of Pathology and Diagnostic Medicine, Khyber Medical University, Peshawar, Pakistan
| | - A Sohail
- Institute of Pathology and Diagnostic Medicine, Khyber Medical University, Peshawar, Pakistan
| | - R Ullah
- Department of Dairy Technology, Faculty of Veterinary and Animal Sciences, University of Agriculture Dera Ismail Khan, Pakistan
| | - A Iqbal
- Faculty of Veterinary and Animal Sciences, Gomal University, Dera Ismail Khan, Pakistan
| | - B Ahmad
- Department of Animal Sciences, Faculty of Veterinary and Animal Sciences, MNS University of Agriculture Multan, Punjab, 25000, Pakistan
| | - I U Khan
- Faculty of Veterinary and Animal Sciences, Gomal University, Dera Ismail Khan, Pakistan
| | - A Tariq
- Directorate of Livestock and Dairy Development Department, Khyber Pakhtunkhwa, Pakistan
| | - M Ahmad
- Department of Animal Sciences, Quaid-E Azam University Islamabad, Pakistan
| | - A Said
- Department of Parasitology, University of Agriculture Faisalabad, Pakistan
| | - S Ullah
- Department of Biochemistry, Hazara University Mansehra, Pakistan
| | - A Ali
- Institute of Pathology and Diagnostic Medicine, Khyber Medical University, Peshawar, Pakistan
| | - M U Rahman
- Institute of Pathology and Diagnostic Medicine, Khyber Medical University, Peshawar, Pakistan
| | - A Zaman
- Faculty of Veterinary and Animal Sciences, Gomal University, Dera Ismail Khan, Pakistan
| | - H Bilal
- Second Affiliated Hospital of Shantou University Medical College, Shantou, China
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Li X, Deng D, Cataltepe G, Román Á, Buckley CR, Cassano Monte‐Bello C, Skirycz A, Caldana C, Haydon MJ. A reactive oxygen species Ca 2+ signalling pathway identified from a chemical screen for modifiers of sugar-activated circadian gene expression. New Phytol 2022; 236:1027-1041. [PMID: 35842791 PMCID: PMC9804775 DOI: 10.1111/nph.18380] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 07/13/2022] [Indexed: 06/10/2023]
Abstract
Sugars are essential metabolites for energy and anabolism that can also act as signals to regulate plant physiology and development. Experimental tools to disrupt major sugar signalling pathways are limited. We performed a chemical screen for modifiers of activation of circadian gene expression by sugars to discover pharmacological tools to investigate and manipulate plant sugar signalling. Using a library of commercially available bioactive compounds, we identified 75 confident hits that modified the response of a circadian luciferase reporter to sucrose in dark-adapted Arabidopsis thaliana seedlings. We validated the transcriptional effect on a subset of the hits and measured their effects on a range of sugar-dependent phenotypes for 13 of these chemicals. Chemicals were identified that appear to influence known and unknown sugar signalling pathways. Pentamidine isethionate was identified as a modifier of a sugar-activated Ca2+ signal that acts as a calmodulin inhibitor downstream of superoxide in a metabolic signalling pathway affecting circadian rhythms, primary metabolism and plant growth. Our data provide a resource of new experimental tools to manipulate plant sugar signalling and identify novel components of these pathways.
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Affiliation(s)
- Xiang Li
- School of BioSciencesUniversity of MelbourneParkvilleVic.3010Australia
| | - Dongjing Deng
- School of BioSciencesUniversity of MelbourneParkvilleVic.3010Australia
| | - Gizem Cataltepe
- School of BioSciencesUniversity of MelbourneParkvilleVic.3010Australia
- Max Planck Institute of Molecular Plant Physiology14476PotsdamGermany
| | - Ángela Román
- School of BioSciencesUniversity of MelbourneParkvilleVic.3010Australia
| | | | | | | | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology14476PotsdamGermany
| | - Michael J. Haydon
- School of BioSciencesUniversity of MelbourneParkvilleVic.3010Australia
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Megha K, Sharma M, Sharma C, Gupta A, Sehgal R, Khurana S. Evaluation of in vitro activity of five antimicrobial agents on Acanthamoeba isolates and their toxicity on human corneal epithelium. Eye (Lond) 2022; 36:1911-1917. [PMID: 34548636 PMCID: PMC9500015 DOI: 10.1038/s41433-021-01768-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 08/12/2021] [Accepted: 09/10/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Acanthamoeba keratitis (AK) is an important cause of ocular morbidity in both contact lens wearers and non wearers. Medical management comprises prolonged empiric treatment with multiple drugs, leading to adverse effects and suboptimal cure. The present study evaluated the efficiency and safety of common antimicrobial agents used in treatment of AK. METHODS Six Acanthamoeba isolates (four AK, two water samples) were axenized and subjected to in vitro susceptibility testing against chlorhexidine, pentamidine isethionate, polymyxin B, miltefosine, and fluconazole to check for trophocidal and cysticidal activity. The safety profile was analysed by observing the cytotoxicity of the highest cidal concentration toward human corneal epithelial cell (HCEC) line. RESULTS Chlorhexidine had the lowest cidal concentration against both cysts and trophozoites (range 4.16-25 μg/ml) followed by pentamidine isethionate (range 25-166.7 μg/ml). Both agents were nontoxic to HCEC. Polymyxin B (range 25-200 μg/ml) and fluconazole (range 64-512 μg/ml) had relatively higher minimum inhibitory concentrations (MIC); fluconazole was nontoxic even at 1024 μg/ml, but cytotoxicity was observed at 400 μg/ml with polymyxin B. Miltefosine was not effective against cysts at tested concentrations. A. castellanii were more susceptible to all agents (except pentamidine isethionate) than A. lenticulata. Clinical isolates were less susceptible to polymyxin B and fluconazole than environmental isolates, reverse was true for miltefosine. CONCLUSION Chlorhexidine and pentamidine isethionate were the most effective and safe agents against both trophozoites and cysts forms of our Acanthamoeba isolates. Fluconazole had higher MIC but was nontoxic. Polymyxin B was effective at high MIC but therapeutic dose was found toxic. Miltefosine, at tested concentrations, could not inhibit cysts of Acanthamoeba. Clinical isolates had higher MICs for polymyxin B and fluconazole.
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Affiliation(s)
- Kirti Megha
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Megha Sharma
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Chayan Sharma
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Amit Gupta
- Department of Ophthalmology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Rakesh Sehgal
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Sumeeta Khurana
- Department of Medical Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
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Cardoso Santos C, Meuser Batista M, Inam Ullah A, Rama Krishna Reddy T, Soeiro MDNC. Drug screening using shape-based virtual screening and in vitro experimental models of cutaneous Leishmaniasis. Parasitology 2021; 148:98-104. [PMID: 33023678 PMCID: PMC11010133 DOI: 10.1017/s0031182020001900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 01/05/2023]
Abstract
Cutaneous leishmaniasis (CL) is one of the most disregarded tropical neglected disease with the occurrence of self-limiting ulcers and triggering mucosal damage and stigmatizing scars, leading to huge public health problems and social negative impacts. Pentavalent antimonials are the first-line drug for CL treatment for over 70 years and present several drawbacks in terms of safety and efficacy. Thus, there is an urgent need to search for non-invasive, non-toxic and potent drug candidates for CL. In this sense, we have implemented a shape-based virtual screening approach and identified a set of 32 hit compounds. In vitro phenotypic screenings were conducted using these hit compounds to check their potential leishmanicidal effect towards Leishmania amazonensis (L. amazonensis). Two (Cp1 and Cp2) out of the 32 compounds revealed promising antiparasitic activities, exhibiting considerable potency against intracellular amastigotes present in peritoneal macrophages (IC50 values of 9.35 and 7.25 μm, respectively). Also, a sterile cidality profile was reached at 20 μm after 48 h of incubation, besides a reasonable selectivity (≈8), quite similarly to pentamidine, a diamidine still in use clinically for leishmaniasis. Cp1 with an oxazolo[4,5-b]pyridine scaffold and Cp2 with benzimidazole scaffold could be developed by lead optimization studies to enhance their leishmanicidal potency.
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Affiliation(s)
- Camila Cardoso Santos
- Laboratory of Cellular Biology (LBC), Oswaldo Cruz Institute (IOC/FIOCRUZ), CEP21040-360, Rio de Janeiro, RJ, Brazil
| | - Marcos Meuser Batista
- Laboratory of Cellular Biology (LBC), Oswaldo Cruz Institute (IOC/FIOCRUZ), CEP21040-360, Rio de Janeiro, RJ, Brazil
| | - Asma Inam Ullah
- The Medicines Research Group, School of Health, Sport and Bioscience, College of Applied Health and Communities, University of East London, Stratford Campus, Water Lane, London, UK
| | - Tummala Rama Krishna Reddy
- The Medicines Research Group, School of Health, Sport and Bioscience, College of Applied Health and Communities, University of East London, Stratford Campus, Water Lane, London, UK
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Kelly ML, Chu CC, Shi H, Ganser LR, Bogerd HP, Huynh K, Hou Y, Cullen BR, Al-Hashimi HM. Understanding the characteristics of nonspecific binding of drug-like compounds to canonical stem-loop RNAs and their implications for functional cellular assays. RNA 2021; 27:12-26. [PMID: 33028652 PMCID: PMC7749633 DOI: 10.1261/rna.076257.120] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 09/26/2020] [Indexed: 05/30/2023]
Abstract
Identifying small molecules that selectively bind an RNA target while discriminating against all other cellular RNAs is an important challenge in RNA-targeted drug discovery. Much effort has been directed toward identifying drug-like small molecules that minimize electrostatic and stacking interactions that lead to nonspecific binding of aminoglycosides and intercalators to many stem-loop RNAs. Many such compounds have been reported to bind RNAs and inhibit their cellular activities. However, target engagement and cellular selectivity assays are not routinely performed, and it is often unclear whether functional activity directly results from specific binding to the target RNA. Here, we examined the propensities of three drug-like compounds, previously shown to bind and inhibit the cellular activities of distinct stem-loop RNAs, to bind and inhibit the cellular activities of two unrelated HIV-1 stem-loop RNAs: the transactivation response element (TAR) and the rev response element stem IIB (RREIIB). All compounds bound TAR and RREIIB in vitro, and two inhibited TAR-dependent transactivation and RRE-dependent viral export in cell-based assays while also exhibiting off-target interactions consistent with nonspecific activity. A survey of X-ray and NMR structures of RNA-small molecule complexes revealed that aminoglycosides and drug-like molecules form hydrogen bonds with functional groups commonly accessible in canonical stem-loop RNA motifs, in contrast to ligands that specifically bind riboswitches. Our results demonstrate that drug-like molecules can nonspecifically bind stem-loop RNAs most likely through hydrogen bonding and electrostatic interactions and reinforce the importance of assaying for off-target interactions and RNA selectivity in vitro and in cells when assessing novel RNA-binders.
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Affiliation(s)
- Megan L Kelly
- Department of Biochemistry, Center for Virology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Chia-Chieh Chu
- Department of Biochemistry, Center for Virology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Honglue Shi
- Department of Chemistry, Center for Virology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Laura R Ganser
- Department of Biochemistry, Center for Virology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Hal P Bogerd
- Department of Molecular Genetics and Microbiology, Center for Virology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Kelly Huynh
- Department of Biochemistry, Center for Virology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Yuze Hou
- Department of Biochemistry, Center for Virology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Bryan R Cullen
- Department of Molecular Genetics and Microbiology, Center for Virology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Center for Virology, Duke University Medical Center, Durham, North Carolina 27710, USA
- Department of Chemistry, Center for Virology, Duke University Medical Center, Durham, North Carolina 27710, USA
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Ndung’u K, Murilla GA, Thuita JK, Ngae GN, Auma JE, Gitonga PK, Thungu DK, Kurgat RK, Chemuliti JK, Mdachi RE. Differential virulence of Trypanosoma brucei rhodesiense isolates does not influence the outcome of treatment with anti-trypanosomal drugs in the mouse model. PLoS One 2020; 15:e0229060. [PMID: 33151938 PMCID: PMC7643984 DOI: 10.1371/journal.pone.0229060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 07/04/2020] [Indexed: 11/19/2022] Open
Abstract
We assessed the virulence and anti-trypanosomal drug sensitivity patterns of Trypanosoma brucei rhodesiense (Tbr) isolates in the Kenya Agricultural and Livestock Research Organization-Biotechnology Research Institute (KALRO-BioRI) cryobank. Specifically, the study focused on Tbr clones originally isolated from the western Kenya/eastern Uganda focus of human African Trypanosomiasis (HAT). Twelve (12) Tbr clones were assessed for virulence using groups(n = 10) of Swiss White Mice monitored for 60 days post infection (dpi). Based on survival time, four classes of virulence were identified: (a) very-acute: 0-15, (b) acute: 16-30, (c) sub-acute: 31-45 and (d) chronic: 46-60 dpi. Other virulence biomarkers identified included: pre-patent period (pp), parasitaemia progression, packed cell volume (PCV) and body weight changes. The test Tbr clones together with KALRO-BioRi reference drug-resistant and drug sensitive isolates were then tested for sensitivity to melarsoprol (mel B), pentamidine, diminazene aceturate and suramin, using mice groups (n = 5) treated with single doses of each drug at 24 hours post infection. Our results showed that the clones were distributed among four classes of virulence as follows: 3/12 (very-acute), 3/12 (acute), 2/12 (sub-acute) and 4/12 (chronic) isolates. Differences in survivorship, parasitaemia progression and PCV were significant (P<0.001) and correlated. The isolate considered to be drug resistant at KALRO-BioRI, KETRI 2538, was confirmed to be resistant to melarsoprol, pentamidine and diminazene aceturate but it was not resistant to suramin. A cure rate of at least 80% was achieved for all test isolates with melarsoprol (1mg/Kg and 20 mg/kg), pentamidine (5 and 20 mg/kg), diminazene aceturate (5 mg/kg) and suramin (5 mg/kg) indicating that the isolates were not resistant to any of the drugs despite the differences in virulence. This study provides evidence of variations in virulence of Tbr clones from a single HAT focus and confirms that this variations is not a significant determinant of isolate sensitivity to anti-trypanosomal drugs.
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Affiliation(s)
- Kariuki Ndung’u
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- * E-mail:
| | - Grace Adira Murilla
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- KAG EAST University, Nairobi, Kenya
| | - John Kibuthu Thuita
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- Meru University of Science and Technology, Meru, Kenya
| | - Geoffrey Njuguna Ngae
- Food Crops Research Institute, Kenya Agricultural and Livestock Research Organization, Nairobi, Kenya
| | - Joanna Eseri Auma
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Purity Kaari Gitonga
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Daniel Kahiga Thungu
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Richard Kiptum Kurgat
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Judith Kusimba Chemuliti
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Raymond Ellie Mdachi
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
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9
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Katte RH, Chou RH, Yu C. Pentamidine inhibit S100A4 - p53 interaction and decreases cell proliferation activity. Arch Biochem Biophys 2020; 691:108442. [PMID: 32649952 DOI: 10.1016/j.abb.2020.108442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 12/14/2022]
Abstract
Metastasis-associated S100A4 protein is a small calcium-binding protein typically overexpressed in several tumor forms, and it is widely accepted that S100A4 plays a significant role in the metastasis of cancer. Tumor suppressor p53 is one of the S100A4's main targets. Previous reports show that through p53, S100A4 regulates collagen expression and cell proliferation. When S100A4 interacts with p53, the S100A4 destabilizes wild type p53. In the current study, based on 1H-15N HSQC NMR experiments and HADDOCK results, S100A4 interacts with the intrinsically unstructured transactivation domain (TAD) of the protein p53 and the pentamidine molecules in the presence of calcium ions. Our results suggest that the p53 TAD and pentamidine molecules share similar binding sites on the S100A4 protein. This observation indicates that a competitive binding mechanism can interfere with the binding of S100A4-p53 and increase the level of p53. Also, we compare different aspects of p53 activity in the WST-1 test using MCF 7 cells. We found that the presence of a pentamidine molecule results in higher p53 activity, which is also reflected in less cell proliferation. Collectively, our results indicate that disrupting the S100A4-p53 interaction would prevent cancer progression, and thus S100A4-p53 inhibitors provide a new avenue for cancer therapy.
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Affiliation(s)
- Revansiddha H Katte
- Department of Chemistry, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Ruey-Hwang Chou
- Graduate Institute of Cancer Biology and Center for Molecular Medicine, China Medical University, Taichung, Taiwan
| | - Chin Yu
- Department of Chemistry, National Tsing Hua University, Hsinchu, 30013, Taiwan.
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10
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Di Sante G, Amadio S, Sampaolese B, Clementi ME, Valentini M, Volonté C, Casalbore P, Ria F, Michetti F. The S100B Inhibitor Pentamidine Ameliorates Clinical Score and Neuropathology of Relapsing-Remitting Multiple Sclerosis Mouse Model. Cells 2020; 9:cells9030748. [PMID: 32197530 PMCID: PMC7140642 DOI: 10.3390/cells9030748] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 12/11/2022] Open
Abstract
S100B is an astrocytic protein acting either as an intracellular regulator or an extracellular signaling molecule. A direct correlation between increased amount of S100B and demyelination and inflammatory processes has been demonstrated. The aim of this study is to investigate the possible role of a small molecule able to bind and inhibit S100B, pentamidine, in the modulation of disease progression in the relapsing–remitting experimental autoimmune encephalomyelitis mouse model of multiple sclerosis. By the daily evaluation of clinical scores and neuropathologic-molecular analysis performed in the central nervous system, we observed that pentamidine is able to delay the acute phase of the disease and to inhibit remission, resulting in an amelioration of clinical score when compared with untreated relapsing–remitting experimental autoimmune encephalomyelitis mice. Moreover, we observed a significant reduction of proinflammatory cytokines expression levels in the brains of treated versus untreated mice, in addition to a reduction of nitric oxide synthase activity. Immunohistochemistry confirmed that the inhibition of S100B was able to modify the neuropathology of the disease, reducing immune infiltrates and partially protecting the brain from the damage. Overall, our results indicate that pentamidine targeting the S100B protein is a novel potential drug to be considered for multiple sclerosis treatment.
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Affiliation(s)
- Gabriele Di Sante
- Department of Translational Medicine and Surgery, Section of General Pathology, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy; (G.D.S.); (M.V.)
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo Agostino Gemelli 1-8, 00168 Rome, Italy
| | - Susanna Amadio
- Cellular Neurobiology Unit, Preclinical Neuroscience, IRCCS Santa Lucia Foundation, Via del Fosso di Fiorano 65, 00143 Rome, Italy; (S.A.); (C.V.)
| | - Beatrice Sampaolese
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta” SCITEC-CNR, Largo Francesco Vito 1, 00168 Rome, Italy; (B.S.); (M.E.C.)
| | - Maria Elisabetta Clementi
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta” SCITEC-CNR, Largo Francesco Vito 1, 00168 Rome, Italy; (B.S.); (M.E.C.)
| | - Mariagrazia Valentini
- Department of Translational Medicine and Surgery, Section of General Pathology, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy; (G.D.S.); (M.V.)
| | - Cinzia Volonté
- Cellular Neurobiology Unit, Preclinical Neuroscience, IRCCS Santa Lucia Foundation, Via del Fosso di Fiorano 65, 00143 Rome, Italy; (S.A.); (C.V.)
- Institute for Systems Analysis and Computer Science, IASI-CNR, Largo Francesco Vito 1, 00168 Rome, Italy;
| | - Patrizia Casalbore
- Institute for Systems Analysis and Computer Science, IASI-CNR, Largo Francesco Vito 1, 00168 Rome, Italy;
| | - Francesco Ria
- Department of Translational Medicine and Surgery, Section of General Pathology, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy; (G.D.S.); (M.V.)
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo Agostino Gemelli 1-8, 00168 Rome, Italy
- Correspondence: (F.R.); (F.M.); Tel.: +39-06-3015-4914 (F.R.); +39-06-3015-5848 (F.M.)
| | - Fabrizio Michetti
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy
- IRCCS San Raffaele Scientific Institute, Università Vita-Salute San Raffaele, 20132 Milan, Italy
- Correspondence: (F.R.); (F.M.); Tel.: +39-06-3015-4914 (F.R.); +39-06-3015-5848 (F.M.)
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11
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Al-Horani RA, Clemons D, Mottamal M. The In Vitro Effects of Pentamidine Isethionate on Coagulation and Fibrinolysis. Molecules 2019; 24:E2146. [PMID: 31174390 PMCID: PMC6600542 DOI: 10.3390/molecules24112146] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 05/30/2019] [Accepted: 05/30/2019] [Indexed: 12/13/2022] Open
Abstract
Pentamidine is bis-oxybenzamidine-based antiprotozoal drug. The parenteral use of pentamidine appears to affect the processes of blood coagulation and/or fibrinolysis resulting in rare but potentially life-threatening blood clot formation. Pentamidine was also found to cause disseminated intravascular coagulation syndrome. To investigate the potential underlying molecular mechanism(s) of pentamidine's effects on coagulation and fibrinolysis, we studied its effects on clotting times in normal and deficient human plasmas. Using normal plasma, pentamidine isethionate doubled the activated partial thromboplastin time at 27.5 µM, doubled the prothrombin time at 45.7 µM, and weakly doubled the thrombin time at 158.17 µM. Using plasmas deficient of factors VIIa, IXa, XIa, or XIIa, the concentrations to double the activated partial thromboplastin time were similar to that obtained using normal plasma. Pentamidine also inhibited plasmin-mediated clot lysis with half-maximal inhibitory concentration (IC50) value of ~3.6 μM. Chromogenic substrate hydrolysis assays indicated that pentamidine inhibits factor Xa and plasmin with IC50 values of 10.4 µM and 8.4 µM, respectively. Interestingly, it did not significantly inhibit thrombin, factor XIa, factor XIIIa, neutrophil elastase, or chymotrypsin at the highest concentrations tested. Michaelis-Menten kinetics and molecular modeling studies revealed that pentamidine inhibits factor Xa and plasmin in a competitive fashion. Overall, this study provides quantitative mechanistic insights into the in vitro effects of pentamidine isethionate on coagulation and fibrinolysis via the disruption of the proteolytic activity of factor Xa and plasmin.
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Affiliation(s)
- Rami A Al-Horani
- Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA 70125, USA.
| | - Daytriona Clemons
- Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA 70125, USA.
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12
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Kanvatirth P, Jeeves RE, Bacon J, Besra GS, Alderwick LJ. Utilisation of the Prestwick Chemical Library to identify drugs that inhibit the growth of mycobacteria. PLoS One 2019; 14:e0213713. [PMID: 30861059 PMCID: PMC6414029 DOI: 10.1371/journal.pone.0213713] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 02/27/2019] [Indexed: 11/19/2022] Open
Abstract
Tuberculosis (TB) is an infectious bacterial disease that kills approximately 1.3 million people every year. Despite global efforts to reduce both the incidence and mortality associated with TB, the emergence of drug resistant strains has slowed any progress made towards combating the spread of this deadly disease. The current TB drug regimen is inadequate, takes months to complete and poses significant challenges when administering to patients suffering from drug resistant TB. New treatments that are faster, simpler and more affordable are urgently required. Arguably, a good strategy to discover new drugs is to start with an old drug. Here, we have screened a library of 1200 FDA approved drugs from the Prestwick Chemical library using a GFP microplate assay. Drugs were screened against GFP expressing strains of Mycobacterium smegmatis and Mycobacterium bovis BCG as surrogates for Mycobacterium tuberculosis, the causative agent of TB in humans. We identified several classes of drugs that displayed antimycobacterial activity against both M. smegmatis and BCG, however each organism also displayed some selectivity towards certain drug classes. Variant analysis of whole genomes sequenced for resistant mutants raised to florfenicol, vanoxerine and pentamidine highlight new pathways that could be exploited in drug repurposing programmes.
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Affiliation(s)
- Panchali Kanvatirth
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Rose E. Jeeves
- TB Research Group, National Infection Service, Public Health England, Porton Down, Salisbury, United Kingdom
| | - Joanna Bacon
- TB Research Group, National Infection Service, Public Health England, Porton Down, Salisbury, United Kingdom
| | - Gurdyal S. Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Luke J. Alderwick
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
- * E-mail:
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13
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Thomas JA, Baker N, Hutchinson S, Dominicus C, Trenaman A, Glover L, Alsford S, Horn D. Insights into antitrypanosomal drug mode-of-action from cytology-based profiling. PLoS Negl Trop Dis 2018; 12:e0006980. [PMID: 30475806 PMCID: PMC6283605 DOI: 10.1371/journal.pntd.0006980] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 12/06/2018] [Accepted: 11/07/2018] [Indexed: 12/31/2022] Open
Abstract
Chemotherapy continues to have a major impact on reducing the burden of disease caused by trypanosomatids. Unfortunately though, the mode-of-action (MoA) of antitrypanosomal drugs typically remains unclear or only partially characterised. This is the case for four of five current drugs used to treat Human African Trypanosomiasis (HAT); eflornithine is a specific inhibitor of ornithine decarboxylase. Here, we used a panel of T. brucei cellular assays to probe the MoA of the current HAT drugs. The assays included DNA-staining followed by microscopy and quantitative image analysis, or flow cytometry; terminal dUTP nick end labelling to monitor mitochondrial (kinetoplast) DNA replication; antibody-based detection of sites of nuclear DNA damage; and fluorescent dye-staining of mitochondria or lysosomes. We found that melarsoprol inhibited mitosis; nifurtimox reduced mitochondrial protein abundance; pentamidine triggered progressive loss of kinetoplast DNA and disruption of mitochondrial membrane potential; and suramin inhibited cytokinesis. Thus, current antitrypanosomal drugs perturb distinct and specific cellular compartments, structures or cell cycle phases. Further exploiting the findings, we show that putative mitogen-activated protein-kinases contribute to the melarsoprol-induced mitotic defect, reminiscent of the mitotic arrest associated signalling cascade triggered by arsenicals in mammalian cells, used to treat leukaemia. Thus, cytology-based profiling can rapidly yield novel insight into antitrypanosomal drug MoA.
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Affiliation(s)
- James A. Thomas
- London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom
| | - Nicola Baker
- The Centre for Immunology and Infection, University of York, Heslington, York, United Kingdom
| | | | | | - Anna Trenaman
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | | | - Sam Alsford
- London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom
| | - David Horn
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
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14
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Cebrero-Cangueiro T, Álvarez-Marín R, Labrador-Herrera G, Smani Y, Cordero-Matía E, Pachón J, Pachón-Ibáñez ME. In vitro Activity of Pentamidine Alone and in Combination With Aminoglycosides, Tigecycline, Rifampicin, and Doripenem Against Clinical Strains of Carbapenemase-Producing and/or Colistin-Resistant Enterobacteriaceae. Front Cell Infect Microbiol 2018; 8:363. [PMID: 30406040 PMCID: PMC6201057 DOI: 10.3389/fcimb.2018.00363] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/01/2018] [Indexed: 12/21/2022] Open
Abstract
Enterobacteriaceae cause different types of community- and hospital-acquired infections. Moreover, the spread of multidrug-resistant Enterobacteriaceae is a public health problem and the World Health Organization pointed them among the pathogens in which the search of new antibiotics is critical. The objective of this study was to analyze the in vitro activity of pentamidine alone and in combination with gentamicin, tobramycin, amikacin, tigecycline, rifampicin, or doripenem against eight clinical strains of carbapenemase-producing and/or colistin-resistant Enterobacteriaceae: five carbapenemase-producing Klebsiella pneumoniae, one carbapenemase-producing Escherichia coli, and two colistin-resistant Enterobacter cloacae. MIC and MBC were determined following standard protocols. MIC results were interpreted for all the antibiotics according to the EUCAST breakpoints but for rifampicin in which the French FSM breakpoint was used. Bactericidal and synergistic activity of pentamidine alone and in combination with antibiotics at concentrations of 1xMIC was measured by time-kill curves. For one selected strain, K. pneumoniae OXA-48/CTX-M-15 time-kill curves were performed also at 1/2xMIC of pentamidine. All studies were performed in triplicate. Pentamidine MIC range was 200-800 μg/mL. The 50, 12.5, 62.5, 87.5, and 62.5% of the strains were susceptible to gentamicin, tobramycin, amikacin, tigecycline, and doripenem, respectively. Only the two E. cloacae strains were susceptible to rifampicin. Pentamidine alone at 1xMIC showed bactericidal activity against all strains, except for the E. cloacae 32 strain. The bactericidal activity of pentamidine alone was also observed in combination. The combinations of pentamidine were synergistic against E. cloacae 32 with amikacin and tobramycin at 24 h and with tigecycline at 8 h. Pentamidine plus rifampicin was the combination that showed synergistic activity against more strains (five out of eight). Pentamidine plus doripenem did not show synergy against any strain. At 1/2xMIC, pentamidine was synergistic with all the studied combinations against the K. pneumoniae OXA-48/CTX-M-15 strain. In summary, pentamidine alone and in combination shows in vitro activity against carbapenemase-producing and/or colistin-resistant Enterobacteriaceae. Pentamidine appears to be a promising option to treat infections caused by these pathogens.
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Affiliation(s)
- Tania Cebrero-Cangueiro
- Clinical Unit of Infectious Diseases, Microbiology, and Preventive Medicine, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
- Institute of Biomedicine of Seville, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
| | - Rocío Álvarez-Marín
- Clinical Unit of Infectious Diseases, Microbiology, and Preventive Medicine, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
- Institute of Biomedicine of Seville, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
| | - Gema Labrador-Herrera
- Clinical Unit of Infectious Diseases, Microbiology, and Preventive Medicine, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
- Institute of Biomedicine of Seville, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
| | - Younes Smani
- Clinical Unit of Infectious Diseases, Microbiology, and Preventive Medicine, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
- Institute of Biomedicine of Seville, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
| | - Elisa Cordero-Matía
- Clinical Unit of Infectious Diseases, Microbiology, and Preventive Medicine, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
- Institute of Biomedicine of Seville, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
| | - Jerónimo Pachón
- Clinical Unit of Infectious Diseases, Microbiology, and Preventive Medicine, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
- Department of Medicine, University of Seville, Seville, Spain
| | - María Eugenia Pachón-Ibáñez
- Clinical Unit of Infectious Diseases, Microbiology, and Preventive Medicine, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
- Institute of Biomedicine of Seville, University Hospital Virgen del Rocío, CSIC, University of Seville, Seville, Spain
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15
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Adams FG, Stroeher UH, Hassan KA, Marri S, Brown MH. Resistance to pentamidine is mediated by AdeAB, regulated by AdeRS, and influenced by growth conditions in Acinetobacter baumannii ATCC 17978. PLoS One 2018; 13:e0197412. [PMID: 29750823 PMCID: PMC5947904 DOI: 10.1371/journal.pone.0197412] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/01/2018] [Indexed: 12/11/2022] Open
Abstract
In recent years, effective treatment of infections caused by Acinetobacter baumannii has become challenging due to the ability of the bacterium to acquire or up-regulate antimicrobial resistance determinants. Two component signal transduction systems are known to regulate expression of virulence factors including multidrug efflux pumps. Here, we investigated the role of the AdeRS two component signal transduction system in regulating the AdeAB efflux system, determined whether AdeA and/or AdeB can individually confer antimicrobial resistance, and explored the interplay between pentamidine resistance and growth conditions in A. baumannii ATCC 17978. Results identified that deletion of adeRS affected resistance towards chlorhexidine and 4',6-diamidino-2-phenylindole dihydrochloride, two previously defined AdeABC substrates, and also identified an 8-fold decrease in resistance to pentamidine. Examination of ΔadeA, ΔadeB and ΔadeAB cells augmented results seen for ΔadeRS and identified a set of dicationic AdeAB substrates. RNA-sequencing of ΔadeRS revealed transcription of 290 genes were ≥2-fold altered compared to the wildtype. Pentamidine shock significantly increased adeA expression in the wildtype, but decreased it in ΔadeRS, implying that AdeRS activates adeAB transcription in ATCC 17978. Investigation under multiple growth conditions, including the use of Biolog phenotypic microarrays, revealed resistance to pentamidine in ATCC 17978 and mutants could be altered by bioavailability of iron or utilization of different carbon sources. In conclusion, the results of this study provide evidence that AdeAB in ATCC 17978 can confer intrinsic resistance to a subset of dicationic compounds and in particular, resistance to pentamidine can be significantly altered depending on the growth conditions.
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Affiliation(s)
- Felise G. Adams
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Uwe H. Stroeher
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Karl A. Hassan
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Shashikanth Marri
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Melissa H. Brown
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
- * E-mail:
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16
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Ji Y, Veldhuis MG, Zandvoort J, Romunde FL, Houtman MJC, Duran K, van Haaften G, Zangerl-Plessl EM, Takanari H, Stary-Weinzinger A, van der Heyden MAG. PA-6 inhibits inward rectifier currents carried by V93I and D172N gain-of-function K IR2.1 channels, but increases channel protein expression. J Biomed Sci 2017; 24:44. [PMID: 28711067 PMCID: PMC5513211 DOI: 10.1186/s12929-017-0352-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/11/2017] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND The inward rectifier potassium current IK1 contributes to a stable resting membrane potential and phase 3 repolarization of the cardiac action potential. KCNJ2 gain-of-function mutations V93I and D172N associate with increased IK1, short QT syndrome type 3 and congenital atrial fibrillation. Pentamidine-Analogue 6 (PA-6) is an efficient (IC50 = 14 nM with inside-out patch clamp methodology) and specific IK1 inhibitor that interacts with the cytoplasmic pore region of the KIR2.1 ion channel, encoded by KCNJ2. At 10 μM, PA-6 increases wild-type (WT) KIR2.1 expression in HEK293T cells upon chronic treatment. We hypothesized that PA-6 will interact with and inhibit V93I and D172N KIR2.1 channels, whereas impact on channel expression at the plasma membrane requires higher concentrations. METHODS Molecular modelling was performed with the human KIR2.1 closed state homology model using FlexX. WT and mutant KIR2.1 channels were expressed in HEK293 cells. Patch-clamp single cell electrophysiology measurements were performed in the whole cell and inside-out mode of the patch clamp method. KIR2.1 expression level and localization were determined by western blot analysis and immunofluorescence microscopy, respectively. RESULTS PA-6 docking in the V93I/D172N double mutant homology model of KIR2.1 demonstrated that mutations and drug-binding site are >30 Å apart. PA-6 inhibited WT and V93I outward currents with similar potency (IC50 = 35.5 and 43.6 nM at +50 mV for WT and V93I), whereas D172N currents were less sensitive (IC50 = 128.9 nM at +50 mV) using inside-out patch-clamp electrophysiology. In whole cell mode, 1 μM of PA-6 inhibited outward IK1 at -50 mV by 28 ± 36%, 18 ± 20% and 10 ± 6%, for WT, V93I and D172N channels respectively. Western blot analysis demonstrated that PA-6 (5 μM, 24 h) increased KIR2.1 expression levels of WT (6.3 ± 1.5 fold), and V93I (3.9 ± 0.9) and D172N (4.8 ± 2.0) mutants. Immunofluorescent microscopy demonstrated dose-dependent intracellular KIR2.1 accumulation following chronic PA-6 application (24 h, 1 and 5 μM). CONCLUSIONS 1) KCNJ2 gain-of-function mutations V93I and D172N in the KIR2.1 ion channel do not impair PA-6 mediated inhibition of IK1, 2) PA-6 elevates KIR2.1 protein expression and induces intracellular KIR2.1 accumulation, 3) PA-6 is a strong candidate for further preclinical evaluation in treatment of congenital SQT3 and AF.
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Affiliation(s)
- Yuan Ji
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marlieke G. Veldhuis
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Jantien Zandvoort
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Fee L. Romunde
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marien J. C. Houtman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Karen Duran
- Center for Molecular Medicine, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gijs van Haaften
- Center for Molecular Medicine, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Hiroki Takanari
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | | | - Marcel A. G. van der Heyden
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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17
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Klein MG, Shou M, Stohlman J, Solhjoo S, Haigney M, Tidwell RR, Goldstein RE, Flagg TP, Haigney MC. Role of suppression of the inward rectifier current in terminal action potential repolarization in the failing heart. Heart Rhythm 2017; 14:1217-1223. [PMID: 28396172 DOI: 10.1016/j.hrthm.2017.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND The failing heart exhibits an increased arrhythmia susceptibility that is often attributed to action potential (AP) prolongation due to significant ion channel remodeling. The inwardly rectifying K+ current (IK1) has been reported to be reduced, but its contribution to shaping the AP waveform and cell excitability in the failing heart remains unclear. OBJECTIVE The purpose of this study was to define the effect of IK1 suppression on the cardiac AP and excitability in the normal and failing hearts. METHODS We used electrophysiological and pharmacological approaches to investigate IK1 function in a swine tachy-pacing model of heart failure (HF). RESULTS Terminal repolarization of the AP (TRAP; the time constant of the exponential fit to terminal repolarization) was markedly prolonged in both myocytes and arterially perfused wedges from animals with HF. TRAP was increased by 54.1% in HF myocytes (P < .001) and 26.2% in HF wedges (P = .014). The increase in TRAP was recapitulated by the potent and specific IK1 inhibitor, PA-6 (pentamidine analog 6), indicating that IK1 is the primary determinant of the final phase of repolarization. Moreover, we find that IK1 suppression reduced the ratio of effective refractory period to AP duration at 90% of repolarization, permitting re-excitation before full repolarization, reduction of AP upstroke velocity, and likely promotion of slow conduction. CONCLUSION Using an objective measure of terminal repolarization, we conclude that IK1 is the major determinant of the terminal repolarization time course. Moreover, suppression of IK1 prolongs repolarization and reduces postrepolarization refractoriness without marked effects on the overall AP duration. Collectively, these findings demonstrate how IK1 suppression may contribute to arrhythmogenesis in the failing heart.
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Affiliation(s)
- Michael G Klein
- Division of Cardiology, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland.
| | - Matie Shou
- Division of Cardiology, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Jayna Stohlman
- Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, Maryland
| | - Soroosh Solhjoo
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Myles Haigney
- Division of Cardiology, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Richard R Tidwell
- Department of Pathology and Laboratory Medicine, School of Medicine, The University of North Carolina, Chapel Hill, North Carolina
| | - Robert E Goldstein
- Division of Cardiology, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Thomas P Flagg
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Mark C Haigney
- Division of Cardiology, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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Abstract
Components within synthetic chemical and natural product extract libraries often interfere with fluorescence-based assays. Fluorescence interference can result when the intrinsic spectral properties of colored compounds overlap with the fluorescent probes. Typically, fluorescence-based protease assays use peptide amidomethylcoumarin derivatives as substrates. However, because many organic compounds absorb in the ultraviolet region, they can interfere with coumarin-based fluorescence assays. Red-shifted fluorescent dyes such as peptidyl rhodamine derivatives are useful because there is generally less interference from organic compounds outside the ultraviolet wavelengths. In this report, rhodamine-based fluorogenic substrates, such as bis-(Leu)2-Rhod110 and bis-(Ala-Pro)2-Rhod110, were developed for leucine aminopeptidase and dipeptidyl aminopeptidase. Novel, tandem rhodamine substrates such as Ala-Pro-Rhod110-Leu were designed with 2 protease cleavage sites and used to assay 2 proteases in a multiplex format. General endpoint high-throughput screening (HTS) assays were also developed for leucine aminopeptidase, dipeptidyl aminopeptidase, and trypsin that incorporated both amidomethylcoumarin and rhodamine-based fluorogenic substrates into a single screening format. These dual-substrate assays allowed for the successful screening of the LOPAC™ collection and natural product extracts despite high levels of fluorescence interference.
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Affiliation(s)
- Stephan K Grant
- Department of Human and Animal Infectious Disease Research, Merck and Co., Rahway, NJ, USA
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Graça NAG, Gaspar L, Costa DM, Loureiro I, Thoo-Lin PK, Ramos I, Roura M, Pruvost A, Pemberton IK, Loukil H, MacDougall J, Tavares J, Cordeiro-da-Silva A. Activity of Bisnaphthalimidopropyl Derivatives against Trypanosoma brucei. Antimicrob Agents Chemother 2016; 60:2532-6. [PMID: 26787703 PMCID: PMC4808195 DOI: 10.1128/aac.02490-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/15/2016] [Indexed: 01/25/2023] Open
Abstract
Current treatments for African trypanosomiasis are either toxic, costly, difficult to administer, or prone to elicit resistance. This study evaluated the activity of bisnaphthalimidopropyl (BNIP) derivatives againstTrypanosoma brucei BNIPDiaminobutane (BNIPDabut), the most active of these compounds, showedin vitroinhibition in the single-unit nanomolar range, similar to the activity in the reference drug pentamidine, and presented low toxicity and adequate metabolic stability. Additionally, using a murine model of acute infection and live imaging, a significant decrease in parasite load in BNIPDabut-treated mice was observed. However, cure was not achieved. BNIPDabut constitutes a new scaffold for antitrypanosomal drugs that deserves further consideration.
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Affiliation(s)
- Nuno A G Graça
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IBMC-Institute for Molecular and Cell Biology, Parasite Disease Group, Porto, Portugal
| | - Luis Gaspar
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IBMC-Institute for Molecular and Cell Biology, Parasite Disease Group, Porto, Portugal
| | - David M Costa
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IBMC-Institute for Molecular and Cell Biology, Parasite Disease Group, Porto, Portugal
| | - Inês Loureiro
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IBMC-Institute for Molecular and Cell Biology, Parasite Disease Group, Porto, Portugal
| | - Paul Kong Thoo-Lin
- Institute for Health & Welfare Research, School of Pharmacy and Life Sciences, Robert Gordon University, Aberdeen, Scotland, United Kingdom
| | | | | | - Alain Pruvost
- CEA, iBiTec-S, SPI, Laboratoire d'Etude du Métabolisme des Médicaments, Gif sur Yvette, France
| | - Ian K Pemberton
- Photeomix, IP Research Consulting SAS, Noisy le Grand, France
| | - Hadjer Loukil
- Photeomix, IP Research Consulting SAS, Noisy le Grand, France
| | - Jane MacDougall
- Photeomix, IP Research Consulting SAS, Noisy le Grand, France
| | - Joana Tavares
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IBMC-Institute for Molecular and Cell Biology, Parasite Disease Group, Porto, Portugal
| | - Anabela Cordeiro-da-Silva
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IBMC-Institute for Molecular and Cell Biology, Parasite Disease Group, Porto, Portugal Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
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Song J, Baker N, Rothert M, Henke B, Jeacock L, Horn D, Beitz E. Pentamidine Is Not a Permeant but a Nanomolar Inhibitor of the Trypanosoma brucei Aquaglyceroporin-2. PLoS Pathog 2016; 12:e1005436. [PMID: 26828608 PMCID: PMC4734766 DOI: 10.1371/journal.ppat.1005436] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 01/12/2016] [Indexed: 11/19/2022] Open
Abstract
The chemotherapeutic arsenal against human African trypanosomiasis, sleeping sickness, is limited and can cause severe, often fatal, side effects. One of the classic and most widely used drugs is pentamidine, an aromatic diamidine compound introduced in the 1940s. Recently, a genome-wide loss-of-function screen and a subsequently generated trypanosome knockout strain revealed a specific aquaglyceroporin, TbAQP2, to be required for high-affinity uptake of pentamidine. Yet, the underlying mechanism remained unclear. Here, we show that TbAQP2 is not a direct transporter for the di-basic, positively charged pentamidine. Even though one of the two common cation filters of aquaglyceroporins, i.e. the aromatic/arginine selectivity filter, is unconventional in TbAQP2, positively charged compounds are still excluded from passing the channel. We found, instead, that the unique selectivity filter layout renders pentamidine a nanomolar inhibitor of TbAQP2 glycerol permeability. Full, non-covalent inhibition of an aqua(glycero)porin in the nanomolar range has not been achieved before. The remarkable affinity derives from an electrostatic interaction with Asp265 and shielding from water as shown by structure-function evaluation and point mutation of Asp265. Exchange of the preceding Leu264 to arginine abolished pentamidine-binding and parasites expressing this mutant were pentamidine-resistant. Our results indicate that TbAQP2 is a high-affinity receptor for pentamidine. Taken together with localization of TbAQP2 in the flagellar pocket of bloodstream trypanosomes, we propose that pentamidine uptake is by endocytosis.
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Affiliation(s)
- Jie Song
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Nicola Baker
- Division of Biological Chemistry & Drug Discovery, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Monja Rothert
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Björn Henke
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Laura Jeacock
- Division of Biological Chemistry & Drug Discovery, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - David Horn
- Division of Biological Chemistry & Drug Discovery, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
- * E-mail:
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Hu RVPF, Straetemans M, Kent AD, Sabajo LOA, de Vries HJC, Lai A Fat RFM. Randomized single-blinded non-inferiority trial of 7 mg/kg pentamidine isethionate versus 4 mg/kg pentamidine isethionate for cutaneous leishmaniaisis in Suriname. PLoS Negl Trop Dis 2015; 9:e0003592. [PMID: 25793773 PMCID: PMC4368628 DOI: 10.1371/journal.pntd.0003592] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 02/05/2015] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Standard treatment of cutaneous leishmaniasis (CL) in Suriname entails three injections of pentamidine isethionate (PI) 4 mg/kg per injection in 7 days (7 day regimen). Compliance to treatment is low and may contribute to increasing therapy failure. A 3 day regimen, including 2 injections of 7 mg/kg in 3 days may increase compliance. METHODS In a randomized, single-blinded non-inferiority trial conducted in Suriname, 84 CL patients received the 7 day regimen and 79 CL patients received the 3 day regimen. Primary objective was the proportion of patients clinically cured at 6 weeks follow-up. Secondary objectives were clinical cure at 12 weeks follow-up; parasitological cure at 6 and 12 weeks; adverse and drug related toxicity events recorded one week after the end of treatment and health related quality of life. The non-inferiority margin was set at 15%, 1 sided test, α = 0.1. RESULTS At 6 weeks follow-up 31 (39%) patients in the 3 day regimen and 41 (49%) patients in the 7 day regimen were clinically cured. Intention to treat (ITT) analyses showed that the difference in proportion clinically cured was -9.6% (90% Confidence Interval (CI): -22.3% to 3.2%). Per protocol (PP) analysis showed that the difference in proportion clinically cured was 0.2% (90% CI: -14.6% to 15.2%). ITT analysis showed that the difference in proportion parasitological cured at 6 weeks was -15.2% (90% CI:-28.0% to -2.5%). PP analyses showed similar results. Non-inferiority could not be concluded for all adverse and toxicological events. CONCLUSION We cannot conclude that the 3 day regimen is non-inferior to the 7 day regimen regarding proportion clinically and parasitological cured. Therefore there is no evidence to change the current standard practice of the 7 day regimen for the treatment of CL in Suriname.
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Affiliation(s)
| | - Masja Straetemans
- Department of Biomedical Research, Royal Tropical Institute, KIT, Amsterdam, The Netherlands
| | - Alida D. Kent
- Department of Parasitology, Anton de Kom University of Suriname, Paramaribo, Suriname
| | | | - Henry J. C. de Vries
- Centre for Infections and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Dermatology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- STI Outpatient Clinic, Cluster Infectious Diseases, Public Health Service Amsterdam, Amsterdam, The Netherlands
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22
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Pyana Pati P, Van Reet N, Mumba Ngoyi D, Ngay Lukusa I, Karhemere Bin Shamamba S, Büscher P. Melarsoprol sensitivity profile of Trypanosoma brucei gambiense isolates from cured and relapsed sleeping sickness patients from the Democratic Republic of the Congo. PLoS Negl Trop Dis 2014; 8:e3212. [PMID: 25275572 PMCID: PMC4183442 DOI: 10.1371/journal.pntd.0003212] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 08/25/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Sleeping sickness caused by Trypanosoma brucei (T.b.) gambiense constitutes a serious health problem in sub-Sahara Africa. In some foci, alarmingly high relapse rates were observed in patients treated with melarsoprol, which used to be the first line treatment for patients in the neurological disease stage. Particularly problematic was the situation in Mbuji-Mayi, East Kasai Province in the Democratic Republic of the Congo with a 57% relapse rate compared to a 5% relapse rate in Masi-Manimba, Bandundu Province. The present study aimed at investigating the mechanisms underlying the high relapse rate in Mbuji-Mayi using an extended collection of recently isolated T.b. gambiense strains from Mbuji-Mayi and from Masi-Manimba. METHODOLOGY/PRINCIPAL FINDINGS Forty five T.b. gambiense strains were used. Forty one were isolated from patients that were cured or relapsed after melarsoprol treatment in Mbuji-Mayi. In vivo drug sensitivity tests provide evidence of reduced melarsoprol sensitivity in these strains. This reduced melarsoprol sensitivity was not attributable to mutations in TbAT1. However, in all these strains, irrespective of the patient treatment outcome, the two aquaglyceroporin (AQP) 2 and 3 genes are replaced by chimeric AQP2/3 genes that may be associated with resistance to pentamidine and melarsoprol. The 4 T.b. gambiense strains isolated in Masi-Manimba contain both wild-type AQP2 and a different chimeric AQP2/3. These findings suggest that the reduced in vivo melarsoprol sensitivity of the Mbuji-Mayi strains and the high relapse rates in that sleeping sickness focus are caused by mutations in the AQP2/AQP3 locus and not by mutations in TbAT1. CONCLUSIONS/SIGNIFICANCE We conclude that mutations in the TbAQP2/3 locus of the local T.b. gambiense strains may explain the high melarsoprol relapse rates in the Mbuji-Mayi focus but other factors must also be involved in the treatment outcome of individual patients.
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Affiliation(s)
- Patient Pyana Pati
- Département de Parasitologie, Institut National de Recherche Biomédicale, Kinshasa Gombe, Democratic Republic of the Congo
- * E-mail:
| | - Nick Van Reet
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Dieudonné Mumba Ngoyi
- Département de Parasitologie, Institut National de Recherche Biomédicale, Kinshasa Gombe, Democratic Republic of the Congo
| | - Ipos Ngay Lukusa
- Département de Parasitologie, Institut National de Recherche Biomédicale, Kinshasa Gombe, Democratic Republic of the Congo
| | - Stomy Karhemere Bin Shamamba
- Département de Parasitologie, Institut National de Recherche Biomédicale, Kinshasa Gombe, Democratic Republic of the Congo
| | - Philippe Büscher
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
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23
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de Albuquerque Melo GM, Silva MCR, Guimarães TP, Pinheiro KM, da Matta CBB, de Queiroz AC, Pivatto M, Bolzani VDS, Alexandre-Moreira MS, Viegas C. Leishmanicidal activity of the crude extract, fractions and major piperidine alkaloids from the flowers of Senna spectabilis. Phytomedicine 2014; 21:277-281. [PMID: 24188737 DOI: 10.1016/j.phymed.2013.09.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/22/2013] [Accepted: 09/29/2013] [Indexed: 06/02/2023]
Abstract
Senna spectabilis (sin. Cassia excelsa, C. spectabilis) is an endemic tree of South America and Africa, very common in Brazil, where it is known as "canafistula-de-besouro" and "cassia-do-nordeste". In folk medicine, this plant is indicated for the treatment of constipation, insomnia, anxiety, epilepsy, malaria, dysentery and headache. Phytopharmacological studies have also confirmed anticonvulsive, sedative, anti-malarial, antimicrobial and cytotoxic properties of many parts of S. spectabilis. In this communication, we present a comparative study of the leishmanicidal activity of the crude ethanolic extract, its fractions and also the two major alkaloidal metabolites (-)-cassine/(-)-spectaline, trying to establish a relationship between the presence of piperidine alkaloidal constituents and leishmanicidal activity. The growth inhibitory effect of promastigote forms of Leishmania major was determined for the crude extract, fractions of the flowers of S. spectabilis and a mixture of (-)-cassine/(-)-spectaline in comparison to pentamidine used as standard drug. The cytotoxic effects were assessed on macrophage strain J774 by lactate dehydrogenase assay. Fractions dichloromethane (FL-DCM) and n-butanol (FL-Bu) and a mixture of (-)-cassine/(-)-spectaline (∼7:3) exhibited significant activity against the parasite Leishmania major (IC50 values of 0.6±0.1 μg/ml, 1.6±0.9 μg/ml and 24.9±1.4 μg/ml, respectively), without toxic effects on murine macrophages. Due to the promising results elicited, further studies in vivo need to be performed to confirm the therapeutic potential of Senna spectabilis.
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Affiliation(s)
| | - Marcela Campelo Rodrigues Silva
- Laboratório de Fitoquímica e Química Medicinal (LFQM), Instituto de Química, Universidade Federal de Alfenas, 37130-000 Alfenas, MG, Brazil
| | - Thaís Pereira Guimarães
- Laboratório de Fitoquímica e Química Medicinal (LFQM), Instituto de Química, Universidade Federal de Alfenas, 37130-000 Alfenas, MG, Brazil
| | - Kátia Mantovani Pinheiro
- Laboratório de Fitoquímica e Química Medicinal (LFQM), Instituto de Química, Universidade Federal de Alfenas, 37130-000 Alfenas, MG, Brazil
| | - Carolina Barbosa Brito da Matta
- Laboratório de Farmacologia e Imunidade, Centro de Ciências Biológicas, Universidade Federal de Alagoas, 57020-720 Maceió, AL, Brazil
| | - Aline Cavalcanti de Queiroz
- Laboratório de Farmacologia e Imunidade, Centro de Ciências Biológicas, Universidade Federal de Alagoas, 57020-720 Maceió, AL, Brazil
| | - Marcos Pivatto
- Núcleo de Bioensaios, Biossíntese e Ecofisiologia de Produtos Naturais (NuBBE), Instituto de Química, Universidade Estadual Paulista, 14801-970 Araraquara, São Paulo, Brazil
| | - Vanderlan da Silva Bolzani
- Núcleo de Bioensaios, Biossíntese e Ecofisiologia de Produtos Naturais (NuBBE), Instituto de Química, Universidade Estadual Paulista, 14801-970 Araraquara, São Paulo, Brazil
| | - Magna Suzana Alexandre-Moreira
- Laboratório de Farmacologia e Imunidade, Centro de Ciências Biológicas, Universidade Federal de Alagoas, 57020-720 Maceió, AL, Brazil.
| | - Claudio Viegas
- Laboratório de Fitoquímica e Química Medicinal (LFQM), Instituto de Química, Universidade Federal de Alfenas, 37130-000 Alfenas, MG, Brazil.
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Graf FE, Ludin P, Wenzler T, Kaiser M, Brun R, Pyana PP, Büscher P, de Koning HP, Horn D, Mäser P. Aquaporin 2 mutations in Trypanosoma brucei gambiense field isolates correlate with decreased susceptibility to pentamidine and melarsoprol. PLoS Negl Trop Dis 2013; 7:e2475. [PMID: 24130910 PMCID: PMC3794916 DOI: 10.1371/journal.pntd.0002475] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 08/28/2013] [Indexed: 12/29/2022] Open
Abstract
The predominant mechanism of drug resistance in African trypanosomes is decreased drug uptake due to loss-of-function mutations in the genes for the transporters that mediate drug import. The role of transporters as determinants of drug susceptibility is well documented from laboratory-selected Trypanosoma brucei mutants. But clinical isolates, especially of T. b. gambiense, are less amenable to experimental investigation since they do not readily grow in culture without prior adaptation. Here we analyze a selected panel of 16 T. brucei ssp. field isolates that (i) have been adapted to axenic in vitro cultivation and (ii) mostly stem from treatment-refractory cases. For each isolate, we quantify the sensitivity to melarsoprol, pentamidine, and diminazene, and sequence the genomic loci of the transporter genes TbAT1 and TbAQP2. The former encodes the well-characterized aminopurine permease P2 which transports several trypanocides including melarsoprol, pentamidine, and diminazene. We find that diminazene-resistant field isolates of T. b. brucei and T. b. rhodesiense carry the same set of point mutations in TbAT1 that was previously described from lab mutants. Aquaglyceroporin 2 has only recently been identified as a second transporter involved in melarsoprol/pentamidine cross-resistance. Here we describe two different kinds of TbAQP2 mutations found in T. b. gambiense field isolates: simple loss of TbAQP2, or loss of wild-type TbAQP2 allele combined with the formation of a novel type of TbAQP2/3 chimera. The identified mutant T. b. gambiense are 40- to 50-fold less sensitive to pentamidine and 3- to 5-times less sensitive to melarsoprol than the reference isolates. We thus demonstrate for the first time that rearrangements of the TbAQP2/TbAQP3 locus accompanied by TbAQP2 gene loss also occur in the field, and that the T. b. gambiense carrying such mutations correlate with a significantly reduced susceptibility to pentamidine and melarsoprol. Human African Trypanosomiasis, or sleeping sickness, is a fatal disease restricted to sub-Saharan Africa, caused by Trypanosoma brucei gambiense and T. b. rhodesiense. The treatment relies on chemotherapy exclusively. Drug resistance in T. brucei was investigated mainly in laboratory-selected lines and found to be linked to mutations in transporters. The adenosine transporter TbAT1 and the aquaglyceroporin TbAQP2 have been implicated in sensitivity to melarsoprol and pentamidine. Mutations in these transporters rendered trypanosomes less susceptible to either drug. Here we analyze T. brucei isolates from the field, focusing on isolates from patients where melarsoprol treatment has failed. We genotype those isolates to test for mutations in TbAQP2 or TbAT1, and phenotype for sensitivity to pentamidine and melarsoprol. Six T. b. gambiense isolates were found to carry mutations in TbAQP2. These isolates stemmed from relapse patients and exhibited significantly reduced sensitivity to pentamidine and melarsoprol as determined in cell culture. These findings indicate that mutations in TbAQP2 are present in the field, correlate with loss of sensitivity to pentamidine and melarsoprol, and might be responsible for melarsoprol treatment failures.
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Affiliation(s)
- Fabrice E. Graf
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Philipp Ludin
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Tanja Wenzler
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Reto Brun
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Patient Pati Pyana
- Institut National de Recherche Biomédicale, Kinshasa-Gombe, Democratic Republic of the Congo
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Philippe Büscher
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Harry P. de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - David Horn
- Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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Qiu G, Jiang J, Liu XS. Pentamidine sensitizes chronic myelogenous leukemia K562 cells to TRAIL-induced apoptosis. Leuk Res 2012; 36:1417-21. [PMID: 22938941 DOI: 10.1016/j.leukres.2012.07.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 06/11/2012] [Accepted: 07/28/2012] [Indexed: 02/05/2023]
Abstract
Pentamidine (PMD) is an anti-protozoa drug with potential anticancer activity. Here we show that PMD at clinically achievable plasma drug concentrations slightly inhibited the growth of human leukemia cell lines. PMD close to its therapeutic doses sensitized TRAIL-resistant K562 cells to the cytokine and potentiated TRAIL-induced apoptosis through activation of caspase-8 and -3. When we investigated the underlying mechanism, we observed that treatment with PMD increased DR5 expression at both mRNA and protein levels and down-regulated anti-apoptotic XIAP and Mcl-1 protein levels. This study provides a rationale for a more in-depth exploration into the combined treatment with PMD and TRAIL as a valuable strategy for leukemia therapy.
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Affiliation(s)
- Geng Qiu
- Department of Biochemistry, Shantou University Medical College, Shantou, Guangdong, China
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Pućkowska A, Drozdowska D, Rusak M, Bielawski T, Bruzgo I, Midura-Nowaczek K. Amino and chlorambucil analogues of pentamidine--synthesis and biological examinations. Acta Pol Pharm 2012; 69:63-73. [PMID: 22574508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The amino analogues of pentamidine with a polymethylene (n = 3 - 6) chain and their chlorambucil derivatives were synthesized. The obtained compounds revealed cytotoxic effect on MCF-7 human breast cancer cell line (IC50 = 22 - 95 +/- 2 pM), mainly by the induction of apoptosis. The topoisomerase I/II inhibition assay and the ethidium displacement assay with the use of pBR322 plasmid DNA were used to the study of mechanism by which the obtained compounds could act. All the compounds are able to bind with DNA and interfere in vitro with the activity of topoisomerase (I and II). The determination of association constants with the use of calf thymus DNA, T4 coliphage DNA, poly(dA-dT)2 and poly(dG-dC)2 showed that the tested compounds bind within minor groove of B-DNA, but not selectively. The alkylating activity of chlorambucil derivatives determined in vitro using a Preussmann test was similar to the activity of chlorambucil. The influence of all the compounds on the amidolytic activity of plasmin and trypsin was also examined. The plasmin activity was inhibited by pentamidine, chlorambucil and aromatic bis-amines (IC50 = 0.1 - 8 mM), whereas the trypsin activity was influenced only by pentamidine.
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Affiliation(s)
- Anna Pućkowska
- Department of Organic Chemistry, Medical University, Mickiewicza 2A, 15-222 Białystok, Poland.
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Cokol M, Chua HN, Tasan M, Mutlu B, Weinstein ZB, Suzuki Y, Nergiz ME, Costanzo M, Baryshnikova A, Giaever G, Nislow C, Myers CL, Andrews BJ, Boone C, Roth FP. Systematic exploration of synergistic drug pairs. Mol Syst Biol 2011; 7:544. [PMID: 22068327 PMCID: PMC3261710 DOI: 10.1038/msb.2011.71] [Citation(s) in RCA: 227] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 08/11/2011] [Indexed: 01/20/2023] Open
Abstract
Drug synergy allows a therapeutic effect to be achieved with lower doses of component drugs. Drug synergy can result when drugs target the products of genes that act in parallel pathways ('specific synergy'). Such cases of drug synergy should tend to correspond to synergistic genetic interaction between the corresponding target genes. Alternatively, 'promiscuous synergy' can arise when one drug non-specifically increases the effects of many other drugs, for example, by increased bioavailability. To assess the relative abundance of these drug synergy types, we examined 200 pairs of antifungal drugs in S. cerevisiae. We found 38 antifungal synergies, 37 of which were novel. While 14 cases of drug synergy corresponded to genetic interaction, 92% of the synergies we discovered involved only six frequently synergistic drugs. Although promiscuity of four drugs can be explained under the bioavailability model, the promiscuity of Tacrolimus and Pentamidine was completely unexpected. While many drug synergies correspond to genetic interactions, the majority of drug synergies appear to result from non-specific promiscuous synergy.
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Affiliation(s)
- Murat Cokol
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Biological Sciences and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
| | - Hon Nian Chua
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Murat Tasan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Beste Mutlu
- Biological Sciences and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
| | - Zohar B Weinstein
- Biological Sciences and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
| | - Yo Suzuki
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Synthetic Biology and Bioenergy, J. Craig Venter Institute, San Diego, CA, USA
| | - Mehmet E Nergiz
- Department of Computer Engineering, Faculty of Engineering, Zirve University, Gaziantep, Turkey
| | - Michael Costanzo
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Anastasia Baryshnikova
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Guri Giaever
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Corey Nislow
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Chad L Myers
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, Minneapolis, MN, USA
| | - Brenda J Andrews
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Charles Boone
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Frederick P Roth
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Samuel Lunenfeld Research Institute, Mt Sinai Hospital, Toronto, Ontario, Canada
- Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, MA, USA
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Jarak I, Marjanović M, Piantanida I, Kralj M, Karminski-Zamola G. Novel pentamidine derivatives: synthesis, anti-tumor properties and polynucleotide-binding activities. Eur J Med Chem 2011; 46:2807-15. [PMID: 21546133 DOI: 10.1016/j.ejmech.2011.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 03/31/2011] [Accepted: 04/01/2011] [Indexed: 11/18/2022]
Abstract
Novel amidino-substituted conformationally restricted derivatives of pentamidine were synthesized and their antiproliferative activity against several human cancer cell lines determined. It was found that introduction of furandicarboxamide core moiety (9, 10) increases antiproliferative activity as well as selectivity against certain tumor cell lines in comparison with amidino-substituted furan-mono-carboxamide (5, 6). Unlike the furan series where iso-propyl substituted amidine (10) exhibits more potent overall antiproliferative activity and selectivity toward certain cell lines, the same was found for unsubstituted amidines in pyridine series. Amongst all tested compounds the compound 10 is the only one that possesses antiproliferative activity against SW 620 cell line (4 μM). Spectroscopic studies of the interactions of prepared diamidines with double-stranded DNA and RNA polynucleotides show that all compounds preferentially bind into the minor groove of DNA, while most of them intercalate into RNA. The structure-dependant biological activity and the lack of DNA/RNA selective binding suggest that the mechanism of action of the here-presented compounds is controlled not only by the interactions with cellular nucleic acids, but also with other more specific protein targets.
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Affiliation(s)
- Ivana Jarak
- Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 20, P.O. Box 177, HR-10000 Zagreb, Croatia
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Paine MF, Wang MZ, Generaux CN, Boykin DW, Wilson WD, De Koning HP, Olson CA, Pohlig G, Burri C, Brun R, Murilla GA, Thuita JK, Barrett MP, Tidwell RR. Diamidines for human African trypanosomiasis. Curr Opin Investig Drugs 2010; 11:876-883. [PMID: 20721830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Aromatic diamidines are potent trypanocides. Pentamidine, a diamidine, has been used for more than 60 years to treat human African trypanosomiasis (HAT); however, the drug must be administered parenterally and is active against first-stage HAT only, prior to the parasites causing neurological deterioration through invasion of the CNS. A major research effort to design novel diamidines has led to the development of orally active prodrugs and, remarkably, a new generation of compounds that can penetrate the CNS. In this review, progress in the development of diamidines for the treatment of HAT is discussed.
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Affiliation(s)
- Mary F Paine
- University of North Carolina at Chapel Hill, Eshelman School of Pharmacy, Campus Box 7569, and Department of Pathology and Laboratory Medicine, Campus Box 7525, Chapel Hill, NC 27599, USA
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Abstract
Four new 5 alpha-pregnane-type steroidal alkaloids, hookerianamides L(1), M(2), N(3), and O(4), and a known N-formylchonemorphine (5) have been isolated by acid-base extraction of the dichloromethane extract of Sarcococca hookeriana. The structures of all compounds were determined with spectroscopic techniques and by comparison with literature data. All compounds displayed antileishmanial and antibacterial properties. Compounds 1, 4, and 5 were found to be more potent than standard pentamidine (IC (50) = 9.59 microg/mL) with respect to leishmanicidal activity. The minimum inhibitory concentration of most of the compounds against Bacillus subtilis, Streptococcus minor, and Streptococcus ferus was lower than that of the standard ampicillin.
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Morales-Yuste M, Morillas-Márquez F, Martín-Sánchez J, Valero-López A, Navarro-Moll MC. Activity of (-)alpha-bisabolol against Leishmania infantum promastigotes. Phytomedicine 2010; 17:279-281. [PMID: 19577452 DOI: 10.1016/j.phymed.2009.05.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 04/30/2009] [Accepted: 05/28/2009] [Indexed: 05/28/2023]
Abstract
Many of the drugs used to treat leishmaniasis are associated with numerous adverse effects. Agents of natural origin have shown activity against different parasites. With this background, an in vitro study was conducted on the activity of (-)alpha-bisabolol, the principal component of Chamomilla recutita essential oil, against Leishmania infantum promastigotes, the main species responsible for human leishmaniasis in Spain. At the two highest concentrations tested (1000 and 500mug/ml), (-)alpha-bisabolol and pentamidine (control agent) achieved 100% inhibition of L. infantum promastigote. These in vitro data can be considered promising in support of the therapeutic use of (-)alpha-bisabolol preparations to treat leishmaniasis caused by L. infantum species.
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Affiliation(s)
- M Morales-Yuste
- Facultad de Farmacia, Departamento de Parasitología, Universidad de Granada, Granada, Spain
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Hu L, Arafa RK, Ismail MA, Patel A, Munde M, Wilson WD, Wenzler T, Brun R, Boykin DW. Synthesis and activity of azaterphenyl diamidines against Trypanosoma brucei rhodesiense and Plasmodium falciparum. Bioorg Med Chem 2009; 17:6651-8. [PMID: 19699098 PMCID: PMC3813006 DOI: 10.1016/j.bmc.2009.07.080] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 07/24/2009] [Accepted: 07/26/2009] [Indexed: 11/24/2022]
Abstract
A series of azaterphenyl diamidines has been synthesized and evaluated for in vitro antiprotozoal activity against both Trypanosoma brucei rhodesiense (T. b. r.) and Plasmodium falciparum (P. f.) and in vivo efficacy in the STIB900 acute mouse model for T. b. r. Six of the 13 compounds showed IC(50) values less than 7 nM against T. b. r. Twelve of those exhibited IC(50) values less than 6 nM against P. f. and six of those showed IC(50) values 0.6 nM, which are more than 25-fold as potent as furamidine. Moreover, two of them showed more than 40-fold selectivity for P. f. versus T. b. r. Three compounds 15b, 19d and 19e exhibited in vivo efficacy against T. b. r. much superior to furamidine, and equivalent to or better than azafuramidine. The antiparasitic activity of these diamidines depends on the ring nitrogen atom(s) location relative to the amidine groups and generally correlates with DNA binding affinity.
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Affiliation(s)
- Laixing Hu
- Department of Chemistry, Georgia State University, Atlanta, GA 30303-3083, USA
| | - Reem K. Arafa
- Department of Chemistry, Georgia State University, Atlanta, GA 30303-3083, USA
| | - Mohamed A. Ismail
- Department of Chemistry, Georgia State University, Atlanta, GA 30303-3083, USA
| | - Alpa Patel
- Department of Chemistry, Georgia State University, Atlanta, GA 30303-3083, USA
| | - Manoj Munde
- Department of Chemistry, Georgia State University, Atlanta, GA 30303-3083, USA
| | - W. David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA 30303-3083, USA
| | - Tanja Wenzler
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, CH-4002 Basel, Switzerland
| | - Reto Brun
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, CH-4002 Basel, Switzerland
| | - David W. Boykin
- Department of Chemistry, Georgia State University, Atlanta, GA 30303-3083, USA
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Genovese G, Tedone L, Hamann MT, Morabito M. The Mediterranean red alga Asparagopsis: a source of compounds against Leishmania. Mar Drugs 2009; 7:361-6. [PMID: 19841720 PMCID: PMC2763106 DOI: 10.3390/md7030361] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 08/07/2009] [Accepted: 08/10/2009] [Indexed: 11/25/2022] Open
Abstract
Crude extracts and column fractions from the red algae Asparagopsis taxiformis and A. armata from the Strait of Messina (Italy) were screened for the production of antimicrobial compounds. Extracts from both species revealed remarkable antiprotozoal activity against Leishmania, revealing such algae as a great source of natural antiprotozoal products.
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Affiliation(s)
- Giuseppa Genovese
- Department of Life Sciences "M. Malpighi"-Botany, University of Messina, Salita Sperone, 31, 98166 Messina, Italy; E-Mails: (L.T.); (M.M.)
- *Author to whom correspondence should be addressed; E-Mail:; Tel.: +39-090-6765628; Fax: +39-090-392686
| | - Laura Tedone
- Department of Life Sciences "M. Malpighi"-Botany, University of Messina, Salita Sperone, 31, 98166 Messina, Italy; E-Mails: (L.T.); (M.M.)
- School of Pharmacy, University of Mississippi, 407 Faser Hall, University MS 38677, USA; E-Mail:
| | - Mark T. Hamann
- School of Pharmacy, University of Mississippi, 407 Faser Hall, University MS 38677, USA; E-Mail:
| | - Marina Morabito
- Department of Life Sciences "M. Malpighi"-Botany, University of Messina, Salita Sperone, 31, 98166 Messina, Italy; E-Mails: (L.T.); (M.M.)
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Sarkar A, Mandal G, Singh N, Sundar S, Chatterjee M. Flow cytometric determination of intracellular non-protein thiols in Leishmania promastigotes using 5-chloromethyl fluorescein diacetate. Exp Parasitol 2009; 122:299-305. [PMID: 19393240 DOI: 10.1016/j.exppara.2009.04.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 04/09/2009] [Accepted: 04/14/2009] [Indexed: 11/19/2022]
Abstract
Leishmania parasites lack catalase and therefore, their anti-oxidant system hinges primarily upon non-protein thiols; accordingly, depletion of thiols could potentially serve as an effective drug target. We have developed a flow cytometry based assay using 5-chloromethyl fluorescein diacetate based upon its selective staining of non-protein thiols. Its specificity was confirmed using buthionine sulphoximine (a gamma-glutamyl cysteine synthetase inhibitor), diamide (an oxidizing agent of intracellular thiols) and N-ethylmaleimide (a covalent modifier of cysteine residues) as evidenced by reduction in fluorescence; furthermore, restoration of fluorescence by N-acetyl cysteine corroborated specificity of 5-chloromethyl fluorescein diacetate to measure non-protein thiols. Differences in basal level of thiols in antimony sensitive and antimony resistant Leishmania field isolates were detected. The depletion of non-protein thiols by conventional anti-leishmanial drugs e.g. antimony and miltefosine was demonstrated. Furthermore, fluorescence was unaffected by depletion of ATP in majority of the strains studied, indicating that 5-chloromethyl fluorescein diacetate is not a substrate for the pump operative in most Leishmania donovani strains. Taken together, measurement of 5-chloromethyl fluorescein diacetate fluorescence is an effective method for monitoring non-protein thiols in Leishmania promastigotes.
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Affiliation(s)
- Avijit Sarkar
- Department of Pharmacology, Institute of Post Graduate Medical Education and Research, Kolkata, 244B Acharya JC Bose Road, Kolkata-700 020, India
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Temporal RM, Cysne-Finkelstein L, Echevarria A, Silva-Gonçalves AJ, Leon LL, Genestra MS. Amidine Derivatives and Leishmania amazonensis: an Evaluation of the Effect of Nitric Oxide (NO) Production on the Parasite-macrophage Interaction. J Enzyme Inhib Med Chem 2008; 20:13-8. [PMID: 15895679 DOI: 10.1080/14756360400015207] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Previous work has demonstrated that N-N'-diphenyl-R-benzamidine was highly effective against Leishmania amazonensis promastigotes/axenic amastigotes and Trypanosoma evansi trypomastigotes and the compound with a methoxy substituent, was the most effective derivative in the parasite-macrophage interaction. Comparative analysis of the nitric oxide (NO) released from the culture infection's supernatant showed the amidine to be less effective than pentamidine Isethionate as a reference drug. Additionally, in order to verify if the methoxylated derivative interferes with NO production by L. amazonensis, the effect of the amidine on the constitutive nitric oxide synthase (cNOS) purified from parasites, was examined, but demonstrated less activity in comparison with the reference drug. This data contributes to studies concerning the metabolic targets present in Leishmania parasites for leishmanicidal drugs.
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Affiliation(s)
- R M Temporal
- Department of Immunology, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, Brazil.
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Pućkowska A, Midura-Nowaczek K, Bruzgo I. Effects of netropsin and pentamidine amino analogues on the amidolytic activity of plasmin, trypsin and urokinase. Acta Pol Pharm 2008; 65:213-215. [PMID: 18666427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Inhibitory effects of nine carbocyclic DNA minor groove binders on amidolytic activities of plasmin, trypsin and urokinase were examined. Some of the studied compounds affected plasmin or trypsin activity, but not urokinase activity. One of the pentamidine analogues (5) and two bis-netropsin like compounds (6, 8) were potent inhibitors of plasmin (IC50 equals 90 and 100 microM), whereas an analogue of netropsin (2) was trypsin inhibitor (IC50 = 100 microM).
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Affiliation(s)
- Anna Pućkowska
- Department of Organic Chemistry, Medical University of Bialystok, ul. Kilińskiego 1, 15-089 Bialystok, Poland.
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Lee MS, Johansen L, Zhang Y, Wilson A, Keegan M, Avery W, Elliott P, Borisy AA, Keith CT. The novel combination of chlorpromazine and pentamidine exerts synergistic antiproliferative effects through dual mitotic action. Cancer Res 2008; 67:11359-67. [PMID: 18056463 DOI: 10.1158/0008-5472.can-07-2235] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Combination therapy has proven successful in treating a wide variety of aggressive human cancers. Historically, combination treatments have been discovered through serendipity or lengthy trials using known anticancer agents with similar indications. We have used combination high-throughput screening to discover the unexpected synergistic combination of an antiparasitic agent, pentamidine, and a phenothiazine antipsychotic, chlorpromazine. This combination, CRx-026, inhibits the growth of tumor cell lines in vivo more effectively than either pentamidine or chlorpromazine alone. Here, we report that CRx-026 exerts its antiproliferative effect through synergistic dual mitotic action. Chlorpromazine is a potent and specific inhibitor of the mitotic kinesin KSP/Eg5 and inhibits tumor cell proliferation through mitotic arrest and accumulation of monopolar spindles. Pentamidine treatment results in chromosomal segregation defects and delayed progression through mitosis, consistent with inhibition of the phosphatase of regenerating liver family of phosphatases. We also show that CRx-026 synergizes in vitro and in vivo with the microtubule-binding agents paclitaxel and vinorelbine. These data support a model where dual action of pentamidine and chlorpromazine in mitosis results in synergistic antitumor effects and show the importance of systematic screening for combinations of targeted agents.
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Affiliation(s)
- Margaret S Lee
- CombinatoRx, Incorporated, 245 First Street, 16th Floor, Cambridge, MA 02142, USA.
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Liu Y, Kumar A, Boykin DW, Wilson WD. Sequence and length dependent thermodynamic differences in heterocyclic diamidine interactions at AT base pairs in the DNA minor groove. Biophys Chem 2007; 131:1-14. [PMID: 17889984 PMCID: PMC2291445 DOI: 10.1016/j.bpc.2007.08.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 08/22/2007] [Accepted: 08/23/2007] [Indexed: 11/17/2022]
Abstract
With the goal of developing a better understanding of the antiparasitic biological action of DB75, we have evaluated its interaction with duplex alternating and nonalternating sequence AT polymers and oligomers. These DNAs provide an important pair of sequences in a detailed thermodynamic analysis of variations in interaction of DB75 with AT sites. The results for DB75 binding to the alternating and nonalternating AT sequences are quite different at the fundamental thermodynamic level. Although the Gibbs energies are similar, the enthalpies for DB75 binding with poly(dA).poly(dT) and poly(dA-dT).poly(dA-dT) are +3.1 and -4.5 kcal/mol, respectively, while the binding entropies are 41.7 and 15.2 cal/mol.K, respectively. The underlying thermodynamics of binding to AT sites in the minor groove plays a key role in the recognition process. It was also observed that DB75 binding with poly(dA).poly(dT) can induce T.A.T triplet formation and the compound binds strongly to the dT.dA.dT triplex.
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Affiliation(s)
| | | | | | - W. David Wilson
- *Corresponding author : W. David Wilson, Department of Chemistry, Georgia State University, Atlanta, GA 30302-4098, USA, Tel: +1-404-413-5503, Fax: +1-404-413-5505,
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39
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Singh G, Dey CS. Induction of apoptosis-like cell death by pentamidine and doxorubicin through differential inhibition of topoisomerase II in arsenite-resistant L. donovani. Acta Trop 2007; 103:172-85. [PMID: 17655815 DOI: 10.1016/j.actatropica.2007.06.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 06/07/2007] [Accepted: 06/11/2007] [Indexed: 11/29/2022]
Abstract
The current study has been undertaken to investigate the sensitivity of the topoisomerase II (topo II) of wild type (Ld-Wt) and arsenite-resistant (Ld-As20) L. donovani to an anti-leishmanial agent pentamidine and an anti-cancer drug doxorubicin. We demonstrate that the cross resistance to pentamidine and doxorubicin in Ld-As20, was in part implicated through differential inhibition of topo II in Ld-Wt and Ld-As20. Further, the treatment of promastigotes at drug concentrations inhibiting 50% of topo II activity inflicted a regulated cell death sharing several apoptotic features like externalization of phosphatidylserine, loss of mitochondrial membrane potential, cytochrome C release into the cytosol, activation of cellular proteases and DNA fragmentation. The cytotoxic potential of pentamidine and doxorubicin in L. donovani has been shown to be mediated through topoisomerase II inhibition and results in inciting programmed cell death process.
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Affiliation(s)
- Gaganmeet Singh
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Punjab, India
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40
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Abstract
S100B protein is one of the factors involved in the down-regulation of tumor suppressor protein p53, a transcription activator that signals for cycle arrest and apoptosis. As the inactivation of normal p53 functions is found in over half of human cancers, restoration of normal p53 functions through the destruction or prevention of S100B--p53 complexes represents a possible approach for the development of anti-cancer drugs. The aim of this work was to propose the S100B binding interface through an examination of the literature and use of molecular modeling (MM) techniques with AutoDock program and the AMBER force field. We propose two residues in the S100B binding pocket (Val56, Phe76) and two residues on the protein surface (Val52, Ala83) are essential for ligand binding. The data presented here indicate that interactions with these four residues are necessary for a reduction in the incidence of the S100B--p53 complex. Additionally, we have tried to explain a mechanism for the action of pentamidine, the best-known S100B ligand, and have proposed two S100B--pentamidine structures. The results presented here may be useful for the efficient design of new S100B ligands.
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Affiliation(s)
- Artur Gieldon
- Protera S. r. l., Viale delle Idee, 22, 50019, Sesto Fiorentino, Fi, Italy.
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41
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Monzote L, Montalvo AM, Scull R, Miranda M, Abreu J. Combined effect of the essential oil from Chenopodium ambrosioides and antileishmanial drugs on promastigotes of Leishmania amazonensis. Rev Inst Med Trop Sao Paulo 2007; 49:257-60. [PMID: 17823757 DOI: 10.1590/s0036-46652007000400012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 11/17/2006] [Indexed: 11/21/2022] Open
Abstract
To date, there are no vaccines against Leishmania, and chemotherapy remains the mainstay for the control of leishmaniasis. The drugs of choice used for leishmaniasis therapy are significantly toxic, expensive and with a growing frequency of refractory infections. Because of these limitations, a combination therapy is the better hope. This work demonstrates that the essential oil from Chenopodium ambrosioides shows a synergic activity after incubation in conjunction with pentamidine against promastigotes of Leishmania amazonensis. However, an indifferent effect has been found for combinations of meglumine antimoniate or amphotericin B and the essential oil.
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Affiliation(s)
- Lianet Monzote
- Departamento de Parasitología, Instituto de Medicina Tropical Pedro Kourí, Ciudad de la Habana, Cuba.
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42
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Cortázar TM, Coombs GH, Walker J. Leishmania panamensis: Comparative inhibition of nuclear DNA topoisomerase II enzymes from promastigotes and human macrophages reveals anti-parasite selectivity of fluoroquinolones, flavonoids and pentamidine. Exp Parasitol 2007; 116:475-82. [PMID: 17466980 DOI: 10.1016/j.exppara.2007.02.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Accepted: 02/28/2007] [Indexed: 10/23/2022]
Abstract
Certain model inhibitors exerted selective action against the catalytic activity of nuclear DNA topoisomerase II (TOPII) of Leishmania panamensis promastigotes. The second-generation fluoroquinolones enoxacin and ciprofloxacin exhibited extraordinarily high anti-parasite selectivity displaying 582- and 40-fold greater potencies against L. panamensis TOPII as compared with the human macrophage enzyme. The flavonoids quercetin and ellagic acid showed inverse specificities, the former being 161-fold more potent against L. panamensis TOPII, and the latter 15.7-fold more active against macrophage TOPII. The protoberberine coralyne was a potent inhibitor of both Leishmania and macrophage TOPII. Bis-benzimidazoles and the diamidine diminazene aceturate exhibited uniformly high potencies against parasite and host TOPII, but a second diamidine pentamidine showed 17.6-fold greater specificity for Leishmania TOPII. The antimonial sodium stibogluconate was an ineffective inhibitor of parasite TOPII showing 4.3-fold greater potency against the macrophage enzyme. These findings suggest that the leishmanicidal activities of certain fluoroquinolones and pentamidine may be mediated partly through TOPII inhibition.
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Affiliation(s)
- Tania M Cortázar
- Centro Internacional de Entrenamiento e Investigaciones Medicas, Cali, Colombia
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43
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Cruz-Monteagudo M, Borges F, Perez González M, Cordeiro MNDS. Computational modeling tools for the design of potent antimalarial bisbenzamidines: Overcoming the antimalarial potential of pentamidine. Bioorg Med Chem 2007; 15:5322-39. [PMID: 17533134 DOI: 10.1016/j.bmc.2007.05.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Revised: 04/24/2007] [Accepted: 05/02/2007] [Indexed: 10/23/2022]
Abstract
Malaria is nowadays a worldwide and serious problem with a significant social, economic, and human cost, mainly in developing countries. In addition, the emergence and spread of resistance to existing antimalarial therapies deteriorate the global malaria situation, and lead thus to an urgent need toward the design and discovery of new antimalarial drugs. In this work, a QSAR predictive model based on GETAWAY descriptors was developed which is able to explain with, only three variables, more than 77% of the variance in antimalarial potency and displays a good internal predictive ability (of 73.3% and 72.9% from leave-one-out cross-validation and bootstrapping analyses, respectively). The performance of the proposed model was judged against other five methodologies providing evidence of the superiority of GETAWAY descriptors in predicting the antimalarial potency of the bisbenzamidine family. Moreover, a desirability analysis based on the final QSAR model showed that to be a useful way of selecting the predictive variable level necessary to obtain potent bisbenzamidines. From the proposed model it is also possible to infer that elevated high atomic masses/polarizabilities/van der Waals volumes could play a negative/positive/positive role in the molecular interactions responsible for the desired drug conformation, which is required for the optimal binding to the macromolecular target. The results obtained point out that our final QSAR model is statistically significant and robust as well as possessing a high predictive effectiveness. Thus, the model provides a feasible and practical tool for looking for new and potent antimalarial bisbenzamidines.
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Affiliation(s)
- Maykel Cruz-Monteagudo
- Applied Chemistry Research Centre, Faculty of Chemistry and Pharmacy, Central University of Las Villas, Santa Clara, Cuba
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44
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Antony S, Marchand C, Stephen AG, Thibaut L, Agama KK, Fisher RJ, Pommier Y. Novel high-throughput electrochemiluminescent assay for identification of human tyrosyl-DNA phosphodiesterase (Tdp1) inhibitors and characterization of furamidine (NSC 305831) as an inhibitor of Tdp1. Nucleic Acids Res 2007; 35:4474-84. [PMID: 17576665 PMCID: PMC1935015 DOI: 10.1093/nar/gkm463] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
By enzymatically hydrolyzing the terminal phosphodiester bond at the 3'-ends of DNA breaks, tyrosyl-DNA phosphodiesterase (Tdp1) repairs topoisomerase-DNA covalent complexes and processes the DNA ends for DNA repair. To identify novel Tdp1 inhibitors, we developed a high-throughput assay that uses electrochemiluminescent (ECL) substrates. Subsequent to screening of 1981 compounds from the 'diversity set' of the NCI-Developmental Therapeutics Program, here we report that furamidine inhibits Tdp1 at low micromolar concentrations. Inhibition of Tdp1 by furamidine is effective both with single- and double-stranded substrates but is slightly stronger with the duplex DNA. Surface plasmon resonance studies show that furamidine binds both single- and double-stranded DNA, though more weakly with the single-stranded substrate DNA. Thus, the inhibition of Tdp1 activity could in part be due to the binding of furamidine to DNA. However, the inhibition of Tdp1 by furamidine is independent of the substrate DNA sequence. The kinetics of Tdp1 inhibition by furamidine was influenced by the drug to enzyme ratio and duration of the reaction. Comparison with related dications shows that furamidine inhibits Tdp1 more effectively than berenil, while pentamidine was inactive. Thus, furamidine represents the most potent Tdp1 inhibitor reported to date.
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Affiliation(s)
- Smitha Antony
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
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45
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Silva CF, Batista MM, Mota RA, de Souza EM, Stephens CE, Som P, Boykin DW, Soeiro MDNC. Activity of “reversed” diamidines against Trypanosoma cruzi “in vitro”. Biochem Pharmacol 2007; 73:1939-46. [PMID: 17462605 DOI: 10.1016/j.bcp.2007.03.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 03/05/2007] [Accepted: 03/20/2007] [Indexed: 11/23/2022]
Abstract
Chagas' disease is an important parasitic illness caused by the flagellated protozoan Trypanosoma cruzi. The disease affects nearly 17 million individuals in endemic areas of Latin America and the current chemotherapy is quite unsatisfactory based on nitroheterocyclic agents (nifurtimox and benznidazol). The need for new compounds with different modes of action is clear. Due to the broad-spectrum antimicrobial activity of the aromatic dicationic compounds, this study focused on the activity of four such diamidines (DB811, DB889, DB786, DB702) and a closely related diguanidine (DB711) against bloodstream trypomastigotes as well as intracellular amastigotes of T. cruzi in vitro. Additional studies were also conducted to access the toxicity of the compounds against mammalian cells in vitro. Our data show that the four diamidines compounds presented early and high anti-parasitic activity (IC50 in low-micromolecular range) exhibiting trypanocidal dose-dependent effects against both trypomastigote and amastigote forms of T. cruzi 2h after drug treatment. Most of the diamidines compounds (except the DB702) exerted high anti-parasitic activity and low toxicity to the mammalian cells. Our results show the activity of reversed diamidines against T. cruzi and suggested that the compounds merit in vivo studies.
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Affiliation(s)
- C F Silva
- Lab. Biologia Celular, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
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46
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Bernhard SC, Nerima B, Mäser P, Brun R. Melarsoprol- and pentamidine-resistant Trypanosoma brucei rhodesiense populations and their cross-resistance. Int J Parasitol 2007; 37:1443-8. [PMID: 17602691 DOI: 10.1016/j.ijpara.2007.05.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Revised: 05/11/2007] [Accepted: 05/15/2007] [Indexed: 11/24/2022]
Abstract
Resistance to melarsoprol and pentamidine was induced in bloodstream-form Trypanosoma brucei rhodesiense STIB 900 in vitro, and drug sensitivity was determined for melarsoprol, pentamidine and furamidine. The resistant populations were also inoculated into immunosuppressed mice to verify infectivity and to monitor whether rodent passage selects for clones with altered drug sensitivity. After proliferation in the mouse, trypanosomes were isolated and their IC(50) values to the three drugs were determined. To assess the stability of drug-induced resistance, drug pressure was ceased for 2 months and the drug sensitivity was determined again. Resistance was stable, with a few exceptions that are discussed. Drug IC(50)s indicated cross-resistance among all drugs, but to varying extents: resistance of the melarsoprol-selected and pentamidine-selected trypanosomes to pentamidine was the same, but the pentamidine-selected trypanosome population showed lower resistance to melarsoprol than the melarsoprol-selected trypanosomes. Interestingly, both resistant populations revealed the same intermediate cross-resistance to furamidine. Resistant trypanosome populations were characterised by molecular means, referring to the status of the TbAT1 gene. The melarsoprol-selected population apparently had lost TbAT1, whereas in the pentamidine-selected trypanosome population it was still present.
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47
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Coelho AC, Messier N, Ouellette M, Cotrim PC. Role of the ABC transporter PRP1 (ABCC7) in pentamidine resistance in Leishmania amastigotes. Antimicrob Agents Chemother 2007; 51:3030-2. [PMID: 17452480 PMCID: PMC1932501 DOI: 10.1128/aac.00404-07] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pentamidine is a second-line agent in the treatment of leishmaniasis whose mode of action and resistance mechanism are not well understood. In this work, we show that the intracellular ABC protein PRP1 (pentamidine resistance protein 1) (ABCC7) can confer resistance to pentamidine in Leishmania sp. parasites in the intracellular stage.
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Affiliation(s)
- Adriano C Coelho
- Instituto de Medicina Tropical, Universidade de São Paulo, Av Dr Enéas de Carvalho Aguiar, 470, 4 andar, São Paulo, Brazil
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Nguewa PA, Fuertes MA, Cepeda V, Iborra S, Carrión J, Valladares B, Alonso C, Pérez JM. Pentamidine is an antiparasitic and apoptotic drug that selectively modifies ubiquitin. Chem Biodivers 2007; 2:1387-400. [PMID: 17191940 DOI: 10.1002/cbdv.200590111] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have determined the cytotoxic properties of pentamidine isethionate (2) towards the promastigotes of the protozoan parasite Leishmania infantum. The leishmanicidal activity of 2 was 60 times higher after 72 h of incubation than that of cisplatin (4). The pentamidine salt 2 induced a higher amount of programmed cell death (PCD) than cisplatin, which is associated with inhibition of DNA synthesis and cell-cycle arrest in the G2/M phase. Circular dichroism (CD) data indicate that binding of 2 to calf-thymus DNA (CT-DNA) induces conformational changes in the DNA double helix, consistent with a B-->A transition. Moreover, the interaction of 2 with ubiquitin led to a 6% increase in the beta-sheet content of the protein as observed by CD spectroscopy. Fluorescence-spectroscopy studies agreed with the CD data, showing that the pentamidine portion of 2 induces a significant decrease in the fluorescence of the Ub residues Phe4 and Phe45 located on the beta-cluster of the molecule, but not of Tyr59 on the alpha-cluster. These data indicate that pentamidine specifically modifies the beta-cluster, i.e., the 'basic face' of ubiquitin. Our results suggest that the biochemical mechanism of action of pentamidine may be a consequence of its dual binding to DNA and proteins.
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Affiliation(s)
- Paul A Nguewa
- Departamento de Parasitología, Facultad de Farmacia, Universidad de la Laguna Tenerife, Spain
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49
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McAllister LA, Hixon MS, Schwartz R, Kubitz DS, Janda KD. Synthesis and Application of a Novel Ligand for Affinity Chromatography Based Removal of Endotoxin from Antibodies. Bioconjug Chem 2007; 18:559-66. [PMID: 17315943 DOI: 10.1021/bc0602984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Endotoxin or lipopolysaccharide (LPS) contamination in proteins expressed by Gram-negative bacteria is a major drawback associated with protein expression. Endotoxin intoxication in humans and animals above a certain threshold level can result in a fatal immune response. Reduction in endotoxin levels is therefore essential before proteins can be used in in vivo studies or sold as pharmaceutical products. Affinity chromatography employing the peptide Polymyxin B (PMB) as an affinity ligand is one way in which endotoxin contamination has been addressed; this is, however, a costly process. We describe the synthesis of a novel affinity ligand based on the structure of the drug pentamidine, which can be applied effectively in endotoxin removal. The synthetic route to this ligand is straightforward and inexpensive, while the ligand can be readily immobilized onto activated sepharose beads. Thus, we demonstrate that these pentamidine affinity beads bind endotoxin/LPS with comparable capacity to PMB affinity systems, that the beads can be recycled efficiently and economically without loss of binding capacity, and application of the functionalized beads for endotoxin removal in an authentic contaminated antibody sample.
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Affiliation(s)
- Laura A McAllister
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, and Worm Institute for Research and Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, USA
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50
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Dudley R, Alsam S, Khan NA. Cellulose biosynthesis pathway is a potential target in the improved treatment of Acanthamoeba keratitis. Appl Microbiol Biotechnol 2007; 75:133-40. [PMID: 17225099 DOI: 10.1007/s00253-006-0793-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 12/04/2006] [Accepted: 12/04/2006] [Indexed: 11/26/2022]
Abstract
Acanthamoeba is an opportunistic protozoan pathogen that can cause blinding keratitis as well as fatal granulomatous encephalitis. One of the distressing aspects in combating Acanthamoeba infections is the prolonged and problematic treatment. For example, current treatment against Acanthamoeba keratitis requires early diagnosis followed by hourly topical application of a mixture of drugs that can last up to a year. The aggressive and prolonged management is due to the ability of Acanthamoeba to rapidly adapt to harsh conditions and switch phenotypes into a resistant cyst form. One possibility of improving the treatment of Acanthamoeba infections is to inhibit the ability of these parasites to switch into the cyst form. The cyst wall is partially made of cellulose. Here, we tested whether a cellulose synthesis inhibitor, 2,6-dichlorobenzonitrile (DCB), can enhance the effects of the antiamoebic drug pentamidine isethionate (PMD). Our findings revealed that DCB can block Acanthamoeba encystment and may improve the antiamoebic effects of PMD. Using in vitro assays, the findings revealed that DCB enhanced the inhibitory effects of PMD on Acanthamoeba binding to and cytotoxicity of the host cells, suggesting the cellulose biosynthesis pathway as a novel target for the improved treatment of Acanthamoeba infections.
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Affiliation(s)
- Ricky Dudley
- School of Biological and Chemical Sciences, Birkbeck College, University of London, London, England, UK
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