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Balta VA, Stiffler D, Sayeed A, Tripathi AK, Elahi R, Mlambo G, Bakshi RP, Dziedzic AG, Jedlicka AE, Nenortas E, Romero-Rodriguez K, Canonizado MA, Mann A, Owen A, Sullivan DJ, Prigge ST, Sinnis P, Shapiro TA. Clinically relevant atovaquone-resistant human malaria parasites fail to transmit by mosquito. Nat Commun 2023; 14:6415. [PMID: 37828012 PMCID: PMC10570281 DOI: 10.1038/s41467-023-42030-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 09/27/2023] [Indexed: 10/14/2023] Open
Abstract
Long-acting injectable medications, such as atovaquone, offer the prospect of a "chemical vaccine" for malaria, combining drug efficacy with vaccine durability. However, selection and transmission of drug-resistant parasites is of concern. Laboratory studies have indicated that atovaquone resistance disadvantages parasites in mosquitoes, but lack of data on clinically relevant Plasmodium falciparum has hampered integration of these variable findings into drug development decisions. Here we generate atovaquone-resistant parasites that differ from wild type parent by only a Y268S mutation in cytochrome b, a modification associated with atovaquone treatment failure in humans. Relative to wild type, Y268S parasites evidence multiple defects, most marked in their development in mosquitoes, whether from Southeast Asia (Anopheles stephensi) or Africa (An. gambiae). Growth of asexual Y268S P. falciparum in human red cells is impaired, but parasite loss in the mosquito is progressive, from reduced gametocyte exflagellation, to smaller number and size of oocysts, and finally to absence of sporozoites. The Y268S mutant fails to transmit from mosquitoes to mice engrafted with human liver cells and erythrocytes. The severe-to-lethal fitness cost of clinically relevant atovaquone resistance to P. falciparum in the mosquito substantially lessens the likelihood of its transmission in the field.
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Affiliation(s)
- Victoria A Balta
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Deborah Stiffler
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Abeer Sayeed
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Abhai K Tripathi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Rubayet Elahi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Godfree Mlambo
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Rahul P Bakshi
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186, USA
| | - Amanda G Dziedzic
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Anne E Jedlicka
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Elizabeth Nenortas
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186, USA
| | - Keyla Romero-Rodriguez
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186, USA
| | - Matthew A Canonizado
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186, USA
| | - Alexis Mann
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Andrew Owen
- Centre of Excellence in Long-acting Therapeutics (CELT), Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, L69 3BX, UK
| | - David J Sullivan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Sean T Prigge
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Photini Sinnis
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Theresa A Shapiro
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA.
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186, USA.
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Balta VA, Stiffler D, Sayeed A, Tripathi AK, Elahi R, Mlambo G, Bakshi RP, Dziedzic AG, Jedlicka AE, Nenortas E, Romero-Rodriguez K, Canonizado MA, Mann A, Owen A, Sullivan DJ, Prigge ST, Sinnis P, Shapiro TA. Transmissibility of clinically relevant atovaquone-resistant Plasmodium falciparum by anopheline mosquitoes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.07.527535. [PMID: 36798298 PMCID: PMC9934642 DOI: 10.1101/2023.02.07.527535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Rising numbers of malaria cases and deaths underscore the need for new interventions. Long-acting injectable medications, such as those now in use for HIV prophylaxis, offer the prospect of a malaria "chemical vaccine", combining the efficacy of a drug (like atovaquone) with the durability of a biological vaccine. Of concern, however, is the possible selection and transmission of drug-resistant parasites. We addressed this question by generating clinically relevant, highly atovaquone-resistant, Plasmodium falciparum mutants competent to infect mosquitoes. Isogenic paired strains, that differ only by a single Y268S mutation in cytochrome b, were evaluated in parallel in southeast Asian (Anopheles stephensi) or African (Anopheles gambiae) mosquitoes, and thence in humanized mice. Fitness costs of the mutation were evident along the lifecycle, in asexual parasite growth in vitro and in a progressive loss of parasites in the mosquito. In numerous independent experiments, microscopic exam of salivary glands from hundreds of mosquitoes failed to detect even one Y268S sporozoite, a defect not rescued by coinfection with wild type parasites. Furthermore, despite uniformly successful transmission of wild type parasites from An. stephensi to FRG NOD huHep mice bearing human hepatocytes and erythrocytes, multiple attempts with Y268S-fed mosquitoes failed: there was no evidence of parasites in mouse tissues by microscopy, in vitro culture, or PCR. These studies confirm a severe-to-lethal fitness cost of clinically relevant atovaquone-resistant P. falciparum in the mosquito, and they significantly lessen the likelihood of their transmission in the field.
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Affiliation(s)
- Victoria A. Balta
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Deborah Stiffler
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Abeer Sayeed
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Abhai K. Tripathi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Rubayet Elahi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Godfree Mlambo
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Rahul P. Bakshi
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186
| | - Amanda G. Dziedzic
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
| | - Anne E. Jedlicka
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
| | - Elizabeth Nenortas
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186
| | - Keyla Romero-Rodriguez
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186
| | - Matthew A. Canonizado
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186
| | - Alexis Mann
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Andrew Owen
- Centre of Excellence in Long-acting Therapeutics (CELT), Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool L69 3BX, UK
| | - David J. Sullivan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Sean T. Prigge
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Photini Sinnis
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
| | - Theresa A. Shapiro
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, 21205
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University, Baltimore, MD, 21205-2186
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Duffy S, Avery VM. Naturally Acquired Kelch13 Mutations in Plasmodium falciparum Strains Modulate In Vitro Ring-Stage Artemisinin-Based Drug Tolerance and Parasite Survival in Response to Hyperoxia. Microbiol Spectr 2022; 10:e0128221. [PMID: 36094220 PMCID: PMC9602862 DOI: 10.1128/spectrum.01282-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 08/25/2022] [Indexed: 12/30/2022] Open
Abstract
The ring-stage survival assay was utilized to assess the impact of physiological hyperoxic stress on dihydroartemisinin (DHA) tolerance for a panel of Plasmodium falciparum strains with and without Kelch13 mutations. Strains without naturally acquired Kelch13 mutations or the postulated genetic background associated with delayed parasite clearance time demonstrated reduced proliferation under hyperoxic conditions in the subsequent proliferation cycle. Dihydroartemisinin tolerance in three isolates with naturally acquired Kelch13 mutations but not two genetically manipulated laboratory strains was modulated by in vitro hyperoxic stress exposure of early-ring-stage parasites in the cycle before drug exposure. Reduced parasite tolerance to additional derivatives, including artemisinin, artesunate, and OZ277, was observed within the second proliferation cycle. OZ439 and epoxomicin completely prevented parasite survival under both hyperoxia and normoxic in vitro culture conditions, highlighting the unique relationship between DHA tolerance and Kelch13 mutation-associated genetic background. IMPORTANCE Artemisinin-based combination therapy (ACT) for treating malaria is under intense scrutiny following treatment failures in the Greater Mekong subregion of Asia. This is further compounded by the potential for extensive loss of life if treatment failures extend to the African continent. Although Plasmodium falciparum has become resistant to all antimalarial drugs, artemisinin "resistance" does not present in the same way as resistance to other antimalarial drugs. Instead, a partial resistance or tolerance is demonstrated, associated with the parasite's genetic profile and linked to a molecular marker referred to as K13. It is suggested that parasites may have adapted to drug treatment, as well as the presence of underlying population health issues such as hemoglobinopathies, and/or environmental pressures, resulting in parasite tolerance to ACT. Understanding parasite evolution and control of artemisinin tolerance will provide innovative approaches to mitigate the development of artemisinin tolerance and thereby artemisinin-based drug treatment failure and loss of life globally to malaria infections.
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Affiliation(s)
- Sandra Duffy
- Discovery Biology, Griffith University, Nathan, Queensland, Australia
| | - Vicky M. Avery
- Discovery Biology, Griffith University, Nathan, Queensland, Australia
- School of Environment and Science, Griffith University, Nathan, Queensland, Australia
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Transcending Dimensions in Apicomplexan Research: from Two-Dimensional to Three-Dimensional In Vitro Cultures. Microbiol Mol Biol Rev 2022; 86:e0002522. [PMID: 35412359 PMCID: PMC9199416 DOI: 10.1128/mmbr.00025-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Parasites belonging to the Apicomplexa phylum are among the most successful pathogens known in nature. They can infect a wide range of hosts, often remain undetected by the immune system, and cause acute and chronic illness. In this phylum, we can find parasites of human and veterinary health relevance, such as Toxoplasma, Plasmodium, Cryptosporidium, and Eimeria. There are still many unknowns about the biology of these pathogens due to the ethical and practical issues of performing research in their natural hosts. Animal models are often difficult or nonexistent, and as a result, there are apicomplexan life cycle stages that have not been studied. One recent alternative has been the use of three-dimensional (3D) systems such as organoids, 3D scaffolds with different matrices, microfluidic devices, organs-on-a-chip, and other tissue culture models. These 3D systems have facilitated and expanded the research of apicomplexans, allowing us to explore life stages that were previously out of reach and experimental procedures that were practically impossible to perform in animal models. Human- and animal-derived 3D systems can be obtained from different organs, allowing us to model host-pathogen interactions for diagnostic methods and vaccine development, drug testing, exploratory biology, and other applications. In this review, we summarize the most recent advances in the use of 3D systems applied to apicomplexans. We show the wide array of strategies that have been successfully used so far and apply them to explore other organisms that have been less studied.
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5
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Lim C, Ramsey JD, Hwang D, Teixeira SCM, Poon CD, Strauss JD, Rosen EP, Sokolsky-Papkov M, Kabanov AV. Drug-Dependent Morphological Transitions in Spherical and Worm-Like Polymeric Micelles Define Stability and Pharmacological Performance of Micellar Drugs. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2103552. [PMID: 34841670 DOI: 10.1002/smll.202103552] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Significant advances in physicochemical properties of polymeric micelles enable optimization of therapeutic drug efficacy, supporting nanomedicine manufacturing and clinical translation. Yet, the effect of micelle morphology on pharmacological efficacy is not adequately addressed. This work addresses this gap by assessing pharmacological efficacy of polymeric micelles with spherical and worm-like morphologies. It is observed that poly(2-oxazoline)-based polymeric micelles can be elongated over time from a spherical structure to worm-like structure, with elongation influenced by several conditions, including the amount and type of drug loaded into the micelles. The role of different morphologies on pharmacological performance of drug loaded micelles against triple-negative breast cancer and pancreatic cancer tumor models is further evaluated. Spherical micelles accumulate rapidly in the tumor tissue while retaining large amounts of drug; worm-like micelles accumulate more slowly and only upon releasing significant amounts of drug. These findings suggest that the dynamic character of the drug-micelle structure and the micelle morphology play a critical role in pharmacological performance, and that spherical micelles are better suited for systemic delivery of anticancer drugs to tumors when drugs are loosely associated with the polymeric micelles.
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Affiliation(s)
- Chaemin Lim
- Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jacob D Ramsey
- Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Duhyeong Hwang
- Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Susana C M Teixeira
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, DE, 19716, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA
| | - Chi-Duen Poon
- Research Computer Center University of North Carolina Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Joshua D Strauss
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Elias P Rosen
- Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Marina Sokolsky-Papkov
- Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Alexander V Kabanov
- Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Laboratory of Chemical Design of Bionanomaterials, Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, 119992, Russia
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6
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Lim C, Ramsey JD, Hwang D, Teixeira SCM, Poon CD, Strauss JD, Rosen EP, Sokolsky-Papkov M, Kabanov AV. Drug-Dependent Morphological Transitions in Spherical and Worm-Like Polymeric Micelles Define Stability and Pharmacological Performance of Micellar Drugs. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2103552. [PMID: 34841670 DOI: 10.1101/2021.06.10.447962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/12/2021] [Indexed: 05/20/2023]
Abstract
Significant advances in physicochemical properties of polymeric micelles enable optimization of therapeutic drug efficacy, supporting nanomedicine manufacturing and clinical translation. Yet, the effect of micelle morphology on pharmacological efficacy is not adequately addressed. This work addresses this gap by assessing pharmacological efficacy of polymeric micelles with spherical and worm-like morphologies. It is observed that poly(2-oxazoline)-based polymeric micelles can be elongated over time from a spherical structure to worm-like structure, with elongation influenced by several conditions, including the amount and type of drug loaded into the micelles. The role of different morphologies on pharmacological performance of drug loaded micelles against triple-negative breast cancer and pancreatic cancer tumor models is further evaluated. Spherical micelles accumulate rapidly in the tumor tissue while retaining large amounts of drug; worm-like micelles accumulate more slowly and only upon releasing significant amounts of drug. These findings suggest that the dynamic character of the drug-micelle structure and the micelle morphology play a critical role in pharmacological performance, and that spherical micelles are better suited for systemic delivery of anticancer drugs to tumors when drugs are loosely associated with the polymeric micelles.
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Affiliation(s)
- Chaemin Lim
- Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jacob D Ramsey
- Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Duhyeong Hwang
- Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Susana C M Teixeira
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, DE, 19716, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, USA
| | - Chi-Duen Poon
- Research Computer Center University of North Carolina Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Joshua D Strauss
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Elias P Rosen
- Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Marina Sokolsky-Papkov
- Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Alexander V Kabanov
- Center for Nanotechnology in Drug Delivery and Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Laboratory of Chemical Design of Bionanomaterials, Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, 119992, Russia
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The Artemiside-Artemisox-Artemisone-M1 Tetrad: Efficacies against Blood Stage P. falciparum Parasites, DMPK Properties, and the Case for Artemiside. Pharmaceutics 2021; 13:pharmaceutics13122066. [PMID: 34959347 PMCID: PMC8704606 DOI: 10.3390/pharmaceutics13122066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 01/15/2023] Open
Abstract
Because of the need to replace the current clinical artemisinins in artemisinin combination therapies, we are evaluating fitness of amino-artemisinins for this purpose. These include the thiomorpholine derivative artemiside obtained in one scalable synthetic step from dihydroartemisinin (DHA) and the derived sulfone artemisone. We have recently shown that artemiside undergoes facile metabolism via the sulfoxide artemisox into artemisone and thence into the unsaturated metabolite M1; DHA is not a metabolite. Artemisox and M1 are now found to be approximately equipotent with artemiside and artemisone in vitro against asexual P. falciparum (Pf) blood stage parasites (IC50 1.5–2.6 nM). Against Pf NF54 blood stage gametocytes, artemisox is potently active (IC50 18.9 nM early-stage, 2.7 nM late-stage), although against the late-stage gametocytes, activity is expressed, like other amino-artemisinins, at a prolonged incubation time of 72 h. Comparative drug metabolism and pharmacokinetic (DMPK) properties were assessed via po and iv administration of artemiside, artemisox, and artemisone in a murine model. Following oral administration, the composite Cmax value of artemiside plus its metabolites artemisox and artemisone formed in vivo is some 2.6-fold higher than that attained following administration of artemisone alone. Given that efficacy of short half-life rapidly-acting antimalarial drugs such as the artemisinins is associated with Cmax, it is apparent that artemiside will be more active than artemisone in vivo, due to additive effects of the metabolites. As is evident from earlier data, artemiside indeed possesses appreciably greater efficacy in vivo against murine malaria. Overall, the higher exposure levels of active drug following administration of artemiside coupled with its synthetic accessibility indicate it is much the preferred drug for incorporation into rational new artemisinin combination therapies.
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8
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Zulfiqar B, Avery VM. Assay development in leishmaniasis drug discovery: a comprehensive review. Expert Opin Drug Discov 2021; 17:151-166. [PMID: 34818139 DOI: 10.1080/17460441.2022.2002843] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Cutaneous, muco-cutaneous and visceral leishmaniasis occur due to an infection with the protozoan parasite Leishmania. The current therapeutic options are limited mainly due to extensive toxicity, emerging resistance and variation in efficacy based on species and strain of the Leishmania parasite. There exists a high unmet medical need to identify new chemical starting points for drug discovery to tackle the disease. AREAS COVERED The authors have highlighted the recent progress, limitations and successes achieved in assay development for leishmaniasis drug discovery. EXPERT OPINION It is true that sophisticated and robust phenotypic in vitro assays have been developed during the last decade, however limitations and challenges remain with respect to variation in activity reported between different research groups and success in translating in vitro outcomes in vivo. The variability is not only due to strain and species differences but also a lack of well-defined criteria and assay conditions, e.g. culture media, host cell type, assay formats, parasite form used, multiplicity of infection and incubation periods. Thus, there is an urgent need for more physiologically relevant assays that encompass multi-species phenotypic approaches to identify new chemical starting points for leishmaniasis drug discovery.
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Affiliation(s)
- Bilal Zulfiqar
- Discovery Biology, Griffith University, Brisbane, Australia
| | - Vicky M Avery
- Discovery Biology, Griffith University, Brisbane, Australia.,Discovery Biology, Griffith University Drug Discovery Programme for Cancer Therapeutics, Brisbane, Australia.,School of Environment and Sciences, Griffith University, Brisbane, Australia
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9
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Ippolito MM, Moser KA, Kabuya JBB, Cunningham C, Juliano JJ. Antimalarial Drug Resistance and Implications for the WHO Global Technical Strategy. CURR EPIDEMIOL REP 2021; 8:46-62. [PMID: 33747712 PMCID: PMC7955901 DOI: 10.1007/s40471-021-00266-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2021] [Indexed: 12/28/2022]
Abstract
PURPOSE OF REVIEW Five years have passed since the World Health Organization released its Global Technical Strategy for Malaria (GTS). In that time, progress against malaria has plateaued. This review focuses on the implications of antimalarial drug resistance for the GTS and how interim progress in parasite genomics and antimalarial pharmacology offer a bulwark against it. RECENT FINDINGS For the first time, drug resistance-conferring genes have been identified and validated before their global expansion in malaria parasite populations. More efficient methods for their detection and elaboration have been developed, although low-density infections and polyclonality remain a nuisance to be solved. Clinical trials of alternative regimens for multidrug-resistant malaria have delivered promising results. New agents continue down the development pipeline, while a nascent infrastructure in sub-Saharan Africa for conducting phase I trials and trials of transmission-blocking agents has come to fruition after years of preparation. SUMMARY These and other developments can help inform the GTS as the world looks ahead to the next two decades of its implementation. To remain ahead of the threat that drug resistance poses, wider application of genomic-based surveillance and optimization of existing and forthcoming antimalarial drugs are essential.
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Affiliation(s)
- Matthew M. Ippolito
- Divisions of Clinical Pharmacology and Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA
- The Johns Hopkins Malaria Research Institute, Johns Hopkins University School of Public Health, Baltimore, MD USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Kara A. Moser
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, NC USA
| | | | - Clark Cunningham
- School of Medicine, University of North Carolina, Chapel Hill, NC USA
| | - Jonathan J. Juliano
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of North Carolina, CB#7030, 130 Mason Farm Rd, Chapel Hill, NC 27599 USA
- Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina, Chapel Hill, NC USA
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
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10
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Ansbro MR, Itkin Z, Chen L, Zahoranszky-Kohalmi G, Amaratunga C, Miotto O, Peryea T, Hobbs CV, Suon S, Sá JM, Dondorp AM, van der Pluijm RW, Wellems TE, Simeonov A, Eastman RT. Modulation of Triple Artemisinin-Based Combination Therapy Pharmacodynamics by Plasmodium falciparum Genotype. ACS Pharmacol Transl Sci 2020; 3:1144-1157. [PMID: 33344893 PMCID: PMC7737215 DOI: 10.1021/acsptsci.0c00110] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Indexed: 01/19/2023]
Abstract
The first-line treatments for uncomplicated Plasmodium falciparum malaria are artemisinin-based combination therapies (ACTs), consisting of an artemisinin derivative combined with a longer acting partner drug. However, the spread of P. falciparum with decreased susceptibility to artemisinin and partner drugs presents a significant challenge to malaria control efforts. To stem the spread of drug resistant parasites, novel chemotherapeutic strategies are being evaluated, including the implementation of triple artemisinin-based combination therapies (TACTs). Currently, there is limited knowledge on the pharmacodynamic and pharmacogenetic interactions of proposed TACT drug combinations. To evaluate these interactions, we established an in vitro high-throughput process for measuring the drug concentration-response to three distinct antimalarial drugs present in a TACT. Sixteen different TACT combinations were screened against 15 parasite lines from Cambodia, with a focus on parasites with differential susceptibilities to piperaquine and artemisinins. Analysis revealed drug-drug interactions unique to specific genetic backgrounds, including antagonism between piperaquine and pyronaridine associated with gene amplification of plasmepsin II/III, two aspartic proteases that localize to the parasite digestive vacuole. From this initial study, we identified parasite genotypes with decreased susceptibility to specific TACTs, as well as potential TACTs that display antagonism in a genotype-dependent manner. Our assay and analysis platform can be further leveraged to inform drug implementation decisions and evaluate next-generation TACTs.
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Affiliation(s)
- Megan R. Ansbro
- Laboratory of Malaria
and Vector Research, National Institute of Allergy and Infectious
Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
- Wellcome Sanger Institute, Hinxton CB10 1SA, U.K.
| | - Zina Itkin
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Lu Chen
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Gergely Zahoranszky-Kohalmi
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Chanaki Amaratunga
- Laboratory of Malaria
and Vector Research, National Institute of Allergy and Infectious
Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Olivo Miotto
- Wellcome Sanger Institute, Hinxton CB10 1SA, U.K.
- Mahidol-Oxford Tropical Medicine Research
Unit, Faculty of Tropical Medicine, Mahidol
University, Bangkok 10400, Thailand
- Centre
for Tropical Medicine and Global Health, Nuffield Department of Medicine
Research, University of Oxford, Oxford OX3 7LF, U.K.
- Medical Research Council (MRC) Centre for Genomics and
Global Health, University of Oxford, Oxford OX3 7BN, U.K.
| | - Tyler Peryea
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Charlotte V. Hobbs
- Division of Infectious Diseases, Children’s
Hospital, University of Mississippi Medical
Center, Jackson, Mississippi 39216, United States
| | - Seila Suon
- National Center for Parasitology, Entomology,
and Malaria Control, Phnom Penh, Cambodia
| | - Juliana M. Sá
- Laboratory of Malaria
and Vector Research, National Institute of Allergy and Infectious
Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Arjen M. Dondorp
- Mahidol-Oxford Tropical Medicine Research
Unit, Faculty of Tropical Medicine, Mahidol
University, Bangkok 10400, Thailand
- Centre
for Tropical Medicine and Global Health, Nuffield Department of Medicine
Research, University of Oxford, Oxford OX3 7LF, U.K.
| | - Rob W. van der Pluijm
- Mahidol-Oxford Tropical Medicine Research
Unit, Faculty of Tropical Medicine, Mahidol
University, Bangkok 10400, Thailand
- Centre
for Tropical Medicine and Global Health, Nuffield Department of Medicine
Research, University of Oxford, Oxford OX3 7LF, U.K.
| | - Thomas E. Wellems
- Laboratory of Malaria
and Vector Research, National Institute of Allergy and Infectious
Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Anton Simeonov
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Richard T. Eastman
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
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11
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Brown AC, Guler JL. From Circulation to Cultivation: Plasmodium In Vivo versus In Vitro. Trends Parasitol 2020; 36:914-926. [DOI: 10.1016/j.pt.2020.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 12/17/2022]
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Meyer KJ, Meyers DJ, Shapiro TA. Optimal kinetic exposures for classic and candidate antitrypanosomals. J Antimicrob Chemother 2020; 74:2303-2310. [PMID: 31093674 DOI: 10.1093/jac/dkz160] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 02/18/2019] [Accepted: 03/20/2019] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVES Efficacy is determined not only by size, but also by shape, of drug exposure. Here the critical importance of the temporal pattern of drug concentrations (pharmacokinetic profile) is examined for antitrypanosomals in vitro. METHODS An in vitro hollow-fibre cartridge system was used to study contrasting drug profiles with four clinically used agents and two experimental candidates against the deadly parasite Trypanosoma brucei. Artificial kinetics were employed intentionally to favour either high peak concentration or sustained duration of drug. RESULTS Changing the shape of drug exposure significantly impacted drug efficacy. Suramin, melarsoprol and pentamidine were concentration-driven and therefore more efficacious when applied as short-lived high peaks. In contrast, difluoromethylornithine (DFMO) was time-driven, and therefore maximally effective as a constant infusion. Kinetic preference was robust over a wide range of drug exposures. Promising clinical candidates SCYX-7158 (acoziborole) and fexinidazole (parent and sulfone) were concentration-driven, suggesting optimal clinical regimens would involve relatively high but intermittent dosing. CONCLUSIONS Antitrypanosomals have an intrinsic pharmacokinetic driver for optimal efficacy, with important implications for clinical management and future candidate development.
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Affiliation(s)
- Kirsten J Meyer
- Division of Clinical Pharmacology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David J Meyers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Theresa A Shapiro
- Division of Clinical Pharmacology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Novel 2D and 3D Assays to Determine the Activity of Anti-Leishmanial Drugs. Microorganisms 2020; 8:microorganisms8060831. [PMID: 32492796 PMCID: PMC7356592 DOI: 10.3390/microorganisms8060831] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/21/2020] [Accepted: 05/25/2020] [Indexed: 12/17/2022] Open
Abstract
The discovery of novel anti-leishmanial compounds remains essential as current treatments have known limitations and there are insufficient novel compounds in development. We have investigated three complex and physiologically relevant in vitro assays, including: (i) a media perfusion based cell culture model, (ii) two 3D cell culture models, and (iii) iPSC derived macrophages in place of primary macrophages or cell lines, to determine whether they offer improved approaches to anti-leishmanial drug discovery and development. Using a Leishmania major amastigote-macrophage assay the activities of standard drugs were investigated to show the effect of changing parameters in these assays. We determined that drug activity was reduced by media perfusion (EC50 values for amphotericin B shifted from 54 (51–57) nM in the static system to 70 (61–75) nM under media perfusion; EC50 values for miltefosine shifted from 12 (11–15) µM in the static system to 30 (26–34) µM under media perfusion) (mean and 95% confidence intervals), with corresponding reduced drug accumulation by macrophages. In the 3D cell culture model there was a significant difference in the EC50 values of amphotericin B but not miltefosine (EC50 values for amphotericin B were 34.9 (31.4–38.6) nM in the 2D and 52.3 (46.6–58.7) nM in 3D; EC50 values for miltefosine were 5.0 (4.9–5.2) µM in 2D and 5.9 (5.5–6.2) µM in 3D (mean and 95% confidence intervals). Finally, in experiments using iPSC derived macrophages infected with Leishmania, reported here for the first time, we observed a higher level of intracellular infection in iPSC derived macrophages compared to the other macrophage types for four different species of Leishmania studied. For L. major with an initial infection ratio of 0.5 parasites per host cell the percentage infection level of the macrophages after 72 h was 11.3% ± 1.5%, 46.0% ± 1.4%, 66.4% ± 3.5% and 75.1% ± 2.4% (average ± SD) for the four cells types, THP1 a human monocytic cell line, mouse bone marrow macrophages (MBMMs), human bone marrow macrophages (HBMMs) and iPSC derived macrophages respectively. Despite the higher infection levels, drug activity in iPSC derived macrophages was similar to that in other macrophage types, for example, amphotericin B EC50 values were 35.9 (33.4–38.5), 33.5 (31.5–36.5), 33.6 (30.5—not calculated (NC)) and 46.4 (45.8–47.2) nM in iPSC, MBMMs, HBMMs and THP1 cells respectively (mean and 95% confidence intervals). We conclude that increasing the complexity of cellular assays does impact upon anti-leishmanial drug activities but not sufficiently to replace the current model used in HTS/HCS assays in drug discovery programmes. The impact of media perfusion on drug activities and the use of iPSC macrophages do, however, deserve further investigation.
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Lucas AJ, Sproston JL, Barton P, Riley RJ. Estimating human ADME properties, pharmacokinetic parameters and likely clinical dose in drug discovery. Expert Opin Drug Discov 2019; 14:1313-1327. [DOI: 10.1080/17460441.2019.1660642] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Adam J. Lucas
- Drug Metabolism and Pharmacokinetics, Evotec, Abingdon, UK
| | | | - Patrick Barton
- Drug Metabolism and Pharmacokinetics, Evotec, Abingdon, UK
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15
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Kinetic Driver of Antibacterial Drugs against Plasmodium falciparum and Implications for Clinical Dosing. Antimicrob Agents Chemother 2019; 63:AAC.00416-19. [PMID: 31451506 DOI: 10.1128/aac.00416-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/07/2019] [Indexed: 01/21/2023] Open
Abstract
Antibacterial drugs are an important component of malaria therapy. We studied the interactions of clindamycin, tetracycline, chloramphenicol, and ciprofloxacin against Plasmodium falciparum under static and dynamic conditions. In microtiter plate assays (static conditions), and as expected, parasites displayed the delayed death response characteristic for apicoplast-targeting drugs. However, rescue by isopentenyl pyrophosphate was variable, ranging from 2,700-fold for clindamycin to just 1.7-fold for ciprofloxacin, suggesting that ciprofloxacin has targets other than the apicoplast. We also examined the pharmacokinetic-pharmacodynamic relationships of these antibacterials in an in vitro glass hollow-fiber system that exposes parasites to dynamically changing drug concentrations. The same total dose and area under the concentration-time curve (AUC) of the drug was deployed either as a single short-lived high peak (bolus) or as a constant low concentration (infusion). All four antibacterials were unambiguously time-driven against malaria parasites: infusions had twice the efficacy of bolus regimens, for the same AUC. The time-dependent efficacy of ciprofloxacin against malaria is in contrast to its concentration-driven action against bacteria. In silico simulations of clinical dosing regimens and resulting pharmacokinetics revealed that current regimens do not maximize time above the MICs of these drugs. Our findings suggest that simple and rational changes to dosing may improve the efficacy of antibacterials against falciparum malaria.
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16
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Meyer KJ, Caton E, Shapiro TA. Model System Identifies Kinetic Driver of Hsp90 Inhibitor Activity against African Trypanosomes and Plasmodium falciparum. Antimicrob Agents Chemother 2018; 62:e00056-18. [PMID: 29866861 PMCID: PMC6105818 DOI: 10.1128/aac.00056-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/26/2018] [Indexed: 12/21/2022] Open
Abstract
Hsp90 inhibitors, well studied in the laboratory and clinic for antitumor indications, have promising activity against protozoan pathogens, including Trypanosoma brucei which causes African sleeping sickness, and the malaria parasite, Plasmodium falciparum To progress these experimental drugs toward clinical use, we adapted an in vitro dynamic hollow-fiber system and deployed artificial pharmacokinetics to discover the driver of their activity: either concentration or time. The activities of compounds from three major classes of Hsp90 inhibitors in development were evaluated against trypanosomes. In all circumstances, the activities of the tested Hsp90 inhibitors were concentration driven. By optimally deploying the drug to match its kinetic driver, the efficacy of a given dose was improved up to 5-fold, and maximal efficacy was achieved with a significantly lower drug exposure. The superiority of concentration-driven regimens was evident in vitro over several logs of drug exposure and was predictive of efficacy in a mouse model of African trypanosomiasis. In studies with P. falciparum, antimalarial activity was similarly concentration driven. This experimental strategy offers an expedient and versatile translational tool to assess the impact of pharmacokinetics on antiprotozoal activity. Knowing kinetic governance early in drug development provides an additional metric for judging lead compounds and allows the incisive design of animal efficacy studies.
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Affiliation(s)
- Kirsten J Meyer
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Emily Caton
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Theresa A Shapiro
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- The Johns Hopkins Malaria Research Institute, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
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17
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Murillo-Solano C, Dong C, Sanchez CG, Pizarro JC. Identification and characterization of the antiplasmodial activity of Hsp90 inhibitors. Malar J 2017; 16:292. [PMID: 28724415 PMCID: PMC5518105 DOI: 10.1186/s12936-017-1940-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 07/14/2017] [Indexed: 01/13/2023] Open
Abstract
Background The recent reduction in mortality due to malaria is being threatened by the appearance of Plasmodium falciparum parasites that are resistant to artemisinin in Southeast Asia. To limit the impact of resistant parasites and their spread across the world, there is a need to validate anti-malarial drug targets and identify new leads that will serve as foundations for future drug development programmes targeting malaria. Towards that end, the antiplasmodial potential of several Hsp90 inhibitors was characterized. Because, the Hsp90 chaperone has been suggested as a good drug target against multiple parasitic infections including malaria. Results Chemically diverse sets of Hsp90 inhibitors, evaluated in clinical trials as anti-cancer agents, were tested against the malaria parasite. Most of the compounds showed strong antiplasmodial activity in growth inhibition assays against chloroquine sensitive and resistant strains. There was a good agreement between the compound in vitro anti-parasitic activity and their affinity against the Plasmodium chaperone. The two most potent Hsp90 inhibitors also showed cytocidal activity against two P. falciparum strains. Their antiplasmodial activity affected all parasite forms during the malaria blood cycle. However, the compounds activity against the parasite showed no synergy when combined with anti-malarial drugs, like chloroquine or DHA. Discussion The Hsp90 inhibitors anti-parasitic activity correlates with their affinity to their predicted target the P. falciparum chaperone Hsp90. However, the most effective compounds also showed high affinity for a close homologue, Grp94. This association points to a mode of action for Hsp90 inhibitors that correlate compound efficacy with multi-target engagement. Besides their ability to limit parasite replication, two compounds also significantly impacted P. falciparum viability in vitro. Finally, a structural analysis suggests that the best hit represents a promising scaffold to develop parasite specific leads according. Conclusion The results shown that Hsp90 inhibitors are lethal against the malaria parasite. The correlation between biochemical and in vitro data strongly supports Hsp90 as a drug target against the malaria parasite. Furthermore, at least one Hsp90 inhibitor developed as anticancer therapeutics could serve as starting point to generate P. falciparum-specific lead compounds. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1940-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Claribel Murillo-Solano
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Chunmin Dong
- Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Cecilia G Sanchez
- Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Juan C Pizarro
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA. .,Vector-Borne Infectious Diseases Research Center, Tulane University, New Orleans, LA, USA.
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18
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Arav-Boger R. Is drug repurposing the answer for cytomegalovirus treatment or prevention? Future Virol 2017. [DOI: 10.2217/fvl-2016-0125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Medical progress has placed cytomegalovirus (CMV) as one of the most important viral pathogens for which treatment is limited and a vaccine is not yet available. The limited treatment options for CMV triggered efforts to discover new antivirals. Drug screening raised hope but also uncertainties as to whether drug repurposing may be a practical approach for infectious diseases in general and CMV in particular. I summarize here several of such agents as well as an approach to advance repurposing for CMV therapy.
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Affiliation(s)
- Ravit Arav-Boger
- Department of Pediatrics, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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19
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Burrows JN, Duparc S, Gutteridge WE, Hooft van Huijsduijnen R, Kaszubska W, Macintyre F, Mazzuri S, Möhrle JJ, Wells TNC. New developments in anti-malarial target candidate and product profiles. Malar J 2017; 16:26. [PMID: 28086874 PMCID: PMC5237200 DOI: 10.1186/s12936-016-1675-x] [Citation(s) in RCA: 305] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/30/2016] [Indexed: 11/10/2022] Open
Abstract
A decade of discovery and development of new anti-malarial medicines has led to a renewed focus on malaria elimination and eradication. Changes in the way new anti-malarial drugs are discovered and developed have led to a dramatic increase in the number and diversity of new molecules presently in pre-clinical and early clinical development. The twin challenges faced can be summarized by multi-drug resistant malaria from the Greater Mekong Sub-region, and the need to provide simplified medicines. This review lists changes in anti-malarial target candidate and target product profiles over the last 4 years. As well as new medicines to treat disease and prevent transmission, there has been increased focus on the longer term goal of finding new medicines for chemoprotection, potentially with long-acting molecules, or parenteral formulations. Other gaps in the malaria armamentarium, such as drugs to treat severe malaria and endectocides (that kill mosquitoes which feed on people who have taken the drug), are defined here. Ultimately the elimination of malaria requires medicines that are safe and well-tolerated to be used in vulnerable populations: in pregnancy, especially the first trimester, and in those suffering from malnutrition or co-infection with other pathogens. These updates reflect the maturing of an understanding of the key challenges in producing the next generation of medicines to control, eliminate and ultimately eradicate malaria.
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Affiliation(s)
- Jeremy N Burrows
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland
| | - Stephan Duparc
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland
| | | | | | - Wiweka Kaszubska
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland
| | - Fiona Macintyre
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland
| | | | - Jörg J Möhrle
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland
| | - Timothy N C Wells
- Medicines for Malaria Venture, Route de Pré Bois 20, 1215, Geneva 15, Switzerland.
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20
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Comparative pharmacokinetics and pharmacodynamics of intravenous artelinate versus artesunate in uncomplicated Plasmodium coatneyi-infected rhesus monkey model. Malar J 2016; 15:453. [PMID: 27599723 PMCID: PMC5011932 DOI: 10.1186/s12936-016-1456-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 07/28/2016] [Indexed: 11/25/2022] Open
Abstract
Background The US Army designed artelinate/lysine salt (AL) to overcome the instability of sodium artesunate in aqueous solution (AS). To select the most efficacious artemisinin treatment, direct comparison was performed in an uncomplicated non-human primate malaria model. Methods Splenectomized rhesus monkeys were inoculated with Plasmodium coatneyi and on day six, single equimolar loading dose of IV AL (11.8 mg kg−1) or IV AS (8 mg kg−1) were administered followed by 1/2 the first dose once daily for 2 more days. Blood smear were performed twice daily and the number of parasites were counted microscopically. Blood samples were obtained after the first dose within 6 h for pharmacokinetic (PK) and ex vivo pharmacodynamic evaluation by simultaneously measuring plasma drug concentration and anti-malarial activity against Plasmodium falciparum in vitro. Results The anti-P. coatneyi in vivo activity of both compounds were comparable, but the ex vivo anti-P. falciparum potency of the IV AS regimen as administered was sevenfold higher than that of IV AL. Comparing in vivo pharmacodynamics of AL and AS, daily assessed parasite counts showed comparable 99 % parasite clearance times (PC99: 2.03, 1.84 day), parasite clearance rates (5.34, 4.13 per min) and clearance half-life (PCt1/2: 7.79, 10.1 h). This study showed strong and significant inverse correlation between PCt1/2 and t1/2 of AS + DHA, and AUC0–∞ of DHA, and correlated with Vz of AS (r2 > 0.7, p ≤ 0.002). Lastly, following IV AL, there was a modest inverse correlation between PCt1/2 and Cmax (r2 0.6, p ≤ 0.04). Although all tested monkeys recrudesced subsequently, two died following AL regimen before parasite clearance. While the aetiology of those deaths could not be definitively determined, pathologic evidence favoured a sepsis-like syndrome and suggested that severe malaria was more likely than drug toxicity. Conclusion The model demonstrated that both AS and DHA contributed to the anti-malarial activity of IV AS, while IV AL activity was largely restricted to the parent drug. Parasite clearance was strongly and linearly dependent on drug exposure for both artemisinin regimens. However, IV AS had higher ex vivo potency against P. falciparum, leading to an IND filing for GMP manufactured AS in the United States. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1456-6) contains supplementary material, which is available to authorized users.
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21
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Caton E, Nenortas E, Bakshi RP, Shapiro TA. Hollow-Fiber Methodology for Pharmacokinetic/Pharmacodynamic Studies of Antimalarial Compounds. CURRENT PROTOCOLS IN CHEMICAL BIOLOGY 2016; 8:29-58. [PMID: 26995353 PMCID: PMC4811375 DOI: 10.1002/9780470559277.ch150194] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Knowledge of pharmacokinetic/pharmacodynamic (PK/PD) relationships can enhance the speed and economy of drug development by enabling informed and rational decisions at every step, from lead selection to clinical dosing. For anti-infective agents in particular, dynamic in vitro hollow-fiber cartridge experiments permit exquisite control of kinetic parameters and the study of their consequent impact on pharmacodynamic efficacy. Such information is of great interest for the cost-restricted but much-needed development of new antimalarial drugs, especially since the major human pathogen Plasmodium falciparum can be cultivated in vitro but is not readily available in animal models. This protocol describes the materials and procedures for determining the PK/PD relationships of antimalarial compounds.
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Affiliation(s)
- Emily Caton
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, and The Johns Hopkins Malaria Research Institute, The Johns Hopkins University, Baltimore, Maryland
| | - Elizabeth Nenortas
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, and The Johns Hopkins Malaria Research Institute, The Johns Hopkins University, Baltimore, Maryland
| | - Rahul P Bakshi
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, and The Johns Hopkins Malaria Research Institute, The Johns Hopkins University, Baltimore, Maryland
| | - Theresa A Shapiro
- Division of Clinical Pharmacology, Departments of Medicine and of Pharmacology and Molecular Sciences, and The Johns Hopkins Malaria Research Institute, The Johns Hopkins University, Baltimore, Maryland
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22
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Ursing J, Rombo L, Bergqvist Y, Rodrigues A, Kofoed PE. High-Dose Chloroquine for Treatment of Chloroquine-Resistant Plasmodium falciparum Malaria. J Infect Dis 2015; 213:1315-21. [PMID: 26656124 DOI: 10.1093/infdis/jiv590] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 11/30/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Due to development of multidrug-resistant Plasmodium falciparum new antimalarial therapies are needed. In Guinea-Bissau, routinely used triple standard-dose chloroquine remained effective for decades despite the existence of "chloroquine-resistant" P. falciparum. This study aimed to determine the in vivo efficacy of higher chloroquine concentrations against P. falciparum with resistance-conferring genotypes. METHODS Standard or double-dose chloroquine was given to 892 children aged <15 years with uncomplicated malaria during 3 clinical trials (2001-2008) with ≥ 35 days follow-up. The P. falciparum resistance-conferring genotype (pfcrt 76T) and day 7 chloroquine concentrations were determined. Data were divided into age groups (<5, 5-9, and 10-14 years) because concentrations increase with age when chloroquine is prescribed according to body weight. RESULTS Adequate clinical and parasitological responses were 14%, 38%, and 39% after standard-dose and 66%, 84%, and 91% after double-dose chloroquine in children aged <5, 5-9, and 10-14 years, respectively, and infected with P. falciparum genotypes conferring chloroquine resistance (n = 195, P < .001). In parallel, median chloroquine concentrations were 471, 688, and 809 nmol/L for standard-dose and 1040, 1494, and 1585 nmol/L for double-dose chloroquine. CONCLUSIONS Chloroquine resistance is dose dependent and can be overcome by higher, still well-tolerated doses.
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Affiliation(s)
- Johan Ursing
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Department of Infectious Diseases, Danderyds Hospital, Stockholm
| | - Lars Rombo
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Centre for Clinical Research, Sörmland County Council, Eskilstuna, and Uppsala University
| | | | | | - Poul-Erik Kofoed
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau Department of Paediatrics, Kolding Hospital, Denmark
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23
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Morada M, Lee S, Gunther-Cummins L, Weiss LM, Widmer G, Tzipori S, Yarlett N. Continuous culture of Cryptosporidium parvum using hollow fiber technology. Int J Parasitol 2015; 46:21-9. [PMID: 26341006 DOI: 10.1016/j.ijpara.2015.07.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 07/23/2015] [Accepted: 07/24/2015] [Indexed: 02/08/2023]
Abstract
Diarrheal disease is a leading cause of pediatric death in economically low resource countries. Cryptosporidium spp. are the second largest member of this group and the only member for which no treatment exists. One of the handicaps to developing chemotherapy is the lack of a reproducible long-term culture method permitting in vitro drug screening beyond 48 h. We have adapted the well-established hollow fiber technology to provide an environment that mimics the gut by delivering nutrients and oxygen from the basal layer upwards while allowing separate redox and nutrient control of the lumen for parasite development. Using this technique, oocyst production was maintained for >6 months, producing approximately 1×10(8)oocysts ml(-1)day(-1), compared with 48 h with a yield of 1×10(6)oocysts ml(-1) in two-dimensional cultures. Oocysts, after 4 and 20 weeks in culture, produced a chronic infection in a TCR-α-deficient mouse model. In vivo infectivity of oocysts was confirmed using oocysts from a 6 week culture in a dexamethasone immunosuppressed mouse model.
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Affiliation(s)
- Mary Morada
- Haskins Laboratories, and Department of Chemistry and Physical Sciences, Pace University, New York, USA
| | - Sangun Lee
- Cummings School of Veterinary Medicine, Tufts University, N. Grafton, MA, USA
| | | | - Louis M Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA; Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Giovanni Widmer
- Cummings School of Veterinary Medicine, Tufts University, N. Grafton, MA, USA
| | - Saul Tzipori
- Cummings School of Veterinary Medicine, Tufts University, N. Grafton, MA, USA
| | - Nigel Yarlett
- Haskins Laboratories, and Department of Chemistry and Physical Sciences, Pace University, New York, USA.
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24
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Synergistic activity of chloroquine with fluconazole against fluconazole-resistant isolates of Candida species. Antimicrob Agents Chemother 2014; 59:1365-9. [PMID: 25512426 DOI: 10.1128/aac.04417-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The in vitro activity of chloroquine and the interactions of chloroquine combined with fluconazole against 37 Candida isolates were tested using the broth microdilution, disk diffusion, and Etest susceptibility tests. Synergistic effect was detected with 6 of 9 fluconazole-resistant Candida albicans isolates, with Candida krusei ATCC 6258, and with all 12 fluconazole-resistant Candida tropicalis isolates.
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25
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Pharmacokinetic-pharmacodynamic analysis of spiroindolone analogs and KAE609 in a murine malaria model. Antimicrob Agents Chemother 2014; 59:1200-10. [PMID: 25487807 PMCID: PMC4335872 DOI: 10.1128/aac.03274-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Limited information is available on the pharmacokinetic (PK) and pharmacodynamic (PD) parameters driving the efficacy of antimalarial drugs. Our objective in this study was to determine dose-response relationships of a panel of related spiroindolone analogs and identify the PK-PD index that correlates best with the efficacy of KAE609, a selected class representative. The dose-response efficacy studies were conducted in the Plasmodium berghei murine malaria model, and the relationship between dose and efficacy (i.e., reduction in parasitemia) was examined. All spiroindolone analogs studied displayed a maximum reduction in parasitemia, with 90% effective dose (ED90) values ranging between 6 and 38 mg/kg of body weight. Further, dose fractionation studies were conducted for KAE609, and the relationship between PK-PD indices and efficacy was analyzed. The PK-PD indices were calculated using the in vitro potency against P. berghei (2× the 99% inhibitory concentration [IC99]) as a threshold (TRE). The percentage of the time in which KAE609 plasma concentrations remained at >2× the IC99 within 48 h (%T>TRE) and the area under the concentration-time curve from 0 to 48 h (AUC0–48)/TRE ratio correlated well with parasite reduction (R2 = 0.97 and 0.95, respectively) but less so for the maximum concentration of drug in serum (Cmax)/TRE ratio (R2 = 0.88). The present results suggest that for KAE609 and, supposedly, for its analogs, the dosing regimens covering a T>TRE of 100%, AUC0–48/TRE ratio of 587, and a Cmax/TRE ratio of 30 are likely to result in the maximum reduction in parasitemia in the P. berghei malaria mouse model. This information could be used to prioritize analogs within the same class of compounds and contribute to the design of efficacy studies, thereby facilitating early drug discovery and lead optimization programs.
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26
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Björnmalm M, Yan Y, Caruso F. Engineering and evaluating drug delivery particles in microfluidic devices. J Control Release 2014; 190:139-49. [DOI: 10.1016/j.jconrel.2014.04.030] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 03/14/2014] [Accepted: 03/21/2014] [Indexed: 02/03/2023]
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27
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Ch'ng JH, Lee YQ, Gun SY, Chia WN, Chang ZW, Wong LK, Batty KT, Russell B, Nosten F, Renia L, Tan KSW. Validation of a chloroquine-induced cell death mechanism for clinical use against malaria. Cell Death Dis 2014; 5:e1305. [PMID: 24967967 PMCID: PMC4611737 DOI: 10.1038/cddis.2014.265] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 04/04/2014] [Accepted: 05/20/2014] [Indexed: 01/09/2023]
Abstract
An alternative antimalarial pathway of an ‘outdated' drug, chloroquine (CQ), may facilitate its return to the shrinking list of effective antimalarials. Conventionally, CQ is believed to interfere with hemozoin formation at nanomolar concentrations, but resistant parasites are able to efflux this drug from the digestive vacuole (DV). However, we show that the DV membrane of both resistant and sensitive laboratory and field parasites is compromised after exposure to micromolar concentrations of CQ, leading to an extrusion of DV proteases. Furthermore, only a short period of exposure is required to compromise the viability of late-stage parasites. To study the feasibility of this strategy, mice malaria models were used to demonstrate that high doses of CQ also triggered DV permeabilization in vivo and reduced reinvasion efficiency. We suggest that a time-release oral formulation of CQ may sustain elevated blood CQ levels sufficiently to clear even CQ-resistant parasites.
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Affiliation(s)
- J-H Ch'ng
- 1] Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore [2] Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels väg 16, KI Solna Campus, Box 280, Stockholm, Sweden
| | - Y-Q Lee
- 1] Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore [2] NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences (CeLS), #05-01, 28 Medical Drive, Singapore, Singapore
| | - S Y Gun
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - W-N Chia
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - Z-W Chang
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - L-K Wong
- Department of Chemistry, National University of Singapore, Block S8, Level 3, 3 Science Drive 3, Singapore, Singapore
| | - K T Batty
- 1] School of Pharmacy, Curtin University, GPO Box U1987, Perth Western Australia 6845 Bentley, WA, Australia [2] West Coast Institute, 35 Kendrew Crescent, Joondalup, WA, Australia
| | - B Russell
- Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore
| | - F Nosten
- 1] Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 68/30 Bantung Road, PO.BOX 46, Maesot, TAK, Thailand [2] Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Churchill Hospital, Old Road, Oxford, UK
| | - L Renia
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - K S-W Tan
- Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore
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Ursing J, Eksborg S, Rombo L, Bergqvist Y, Blessborn D, Rodrigues A, Kofoed PE. Chloroquine is grossly under dosed in young children with malaria: implications for drug resistance. PLoS One 2014; 9:e86801. [PMID: 24466245 PMCID: PMC3900653 DOI: 10.1371/journal.pone.0086801] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/13/2013] [Indexed: 01/09/2023] Open
Abstract
Background Plasmodium falciparum malaria is treated with 25 mg/kg of chloroquine (CQ) irrespective of age. Theoretically, CQ should be dosed according to body surface area (BSA). The effect of dosing CQ according to BSA has not been determined but doubling the dose per kg doubled the efficacy of CQ in children aged <15 years infected with P. falciparum carrying CQ resistance causing genes typical for Africa. The study aim was to determine the effect of age on CQ concentrations. Methods and Findings Day 7 whole blood CQ concentrations were determined in 150 and 302 children treated with 25 and 50 mg/kg, respectively, in previously conducted clinical trials. CQ concentrations normalised for the dose taken in mg/kg of CQ decreased with decreasing age (p<0.001). CQ concentrations normalised for dose taken in mg/m2 were unaffected by age. The median CQ concentration in children aged <2 years taking 50 mg/kg and in children aged 10–14 years taking 25 mg/kg were 825 (95% confidence interval [CI] 662–988) and 758 (95% CI 640–876) nmol/l, respectively (p = 0.67). The median CQ concentration in children aged 10–14 taking 50 mg/kg and children aged 0–2 taking 25 mg/kg were 1521 and 549 nmol/l. Adverse events were not age/concentration dependent. Conclusions CQ is under-dosed in children and should ideally be dosed according to BSA. Children aged <2 years need approximately double the dose per kg to attain CQ concentrations found in children aged 10–14 years. Clinical trials assessing the efficacy of CQ in Africa are typically performed in children aged <5 years. Thus the efficacy of CQ is typically assessed in children in whom CQ is under dosed. Approximately 3 fold higher drug concentrations can probably be safely given to the youngest children. As CQ resistance is concentration dependent an alternative dosing of CQ may overcome resistance in Africa.
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Affiliation(s)
- Johan Ursing
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
- Malaria Research Laboratory, Department of Medicine, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
| | - Staffan Eksborg
- Department of Women’s and Children’s Health, Childhood Cancer Research Unit, Karolinska Institutet, Stockholm, Sweden
| | - Lars Rombo
- Malaria Research Laboratory, Department of Medicine, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
- Centre for Clinical Research, Sörmland, Uppsala University, Sweden
| | | | - Daniel Blessborn
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Poul-Erik Kofoed
- Projecto de Saúde de Bandim, Indepth Network, Bissau, Guinea-Bissau
- Department of Paediatrics, Kolding Hospital, Kolding, Denmark
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29
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A process similar to autophagy is associated with cytocidal chloroquine resistance in Plasmodium falciparum. PLoS One 2013; 8:e79059. [PMID: 24278114 PMCID: PMC3835802 DOI: 10.1371/journal.pone.0079059] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 09/24/2013] [Indexed: 12/31/2022] Open
Abstract
Resistance to the cytostatic activity of the antimalarial drug chloroquine (CQ) is becoming well understood, however, resistance to cytocidal effects of CQ is largely unexplored. We find that PfCRT mutations that almost fully recapitulate P. falciparum cytostatic CQ resistance (CQRCS) as quantified by CQ IC50 shift, account for only 10–20% of cytocidal CQR (CQRCC) as quantified by CQ LD50 shift. Quantitative trait loci (QTL) analysis of the progeny of a chloroquine sensitive (CQS; strain HB3)×chloroquine resistant (CQR; strain Dd2) genetic cross identifies distinct genetic architectures for CQRCS vs CQRCC phenotypes, including identification of novel interacting chromosomal loci that influence CQ LD50. Candidate genes in these loci are consistent with a role for autophagy in CQRCC, leading us to directly examine the autophagy pathway in intraerythrocytic CQR parasites. Indirect immunofluorescence of RBC infected with synchronized CQS vs CQR trophozoite stage parasites reveals differences in the distribution of the autophagy marker protein PfATG8 coinciding with CQRCC. Taken together, the data show that an unusual autophagy – like process is either activated or inhibited for intraerythrocytic trophozoite parasites at LD50 doses (but not IC50 doses) of CQ, that the pathway is altered in CQR P. falciparum, and that it may contribute along with mutations in PfCRT to confer the CQRCC phenotype.
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