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Lewin AC, Ineck NE, Mironovich MA, Marino ME, Liu CC, Emelogu U, Mills EP, Camacho-Luna P, Carter RT. Surveillance for feline herpesvirus type 1 mutation and development of resistance in cats treated with antiviral medications. Front Vet Sci 2023; 10:1197249. [PMID: 37275610 PMCID: PMC10232796 DOI: 10.3389/fvets.2023.1197249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/02/2023] [Indexed: 06/07/2023] Open
Abstract
Feline herpesvirus type 1 (FHV-1) commonly causes ocular surface disease in cats and is treated with antiviral medications targeting viral DNA polymerase (UL30/42). Herein, we describe a method to assess the FHV-1 genome for mutation development and to assess the functional impact of mutations, if present. Fourteen shelter-housed domestic cats with FHV-1 ocular surface disease were assigned to one of four treatment groups: placebo (n = 3), cidofovir 0.5% ophthalmic solution (n = 3), famciclovir oral solution (n = 5), or ganciclovir 0.15% ophthalmic solution (n = 3). Swabs were collected before (day 1) and after (day 8) 1 week of twice-daily treatments to isolate viable FHV-1. Viral DNA was extracted for sequencing using Illumina MiSeq with subsequent genomic variant detection between paired day 1 and day 8 isolates. Plaque reduction assay was performed on paired isolates demonstrating non-synonymous variants. A total of 171 synonymous and 3 non-synonymous variants were identified in day 8 isolates. No variants were detected in viral UL23, UL30, or UL42 genes. Variant totals were not statistically different in animals receiving antiviral or placebo (p = 0.4997). A day 8 isolate from each antiviral treatment group contained a single non-synonymous variant in ICP4 (transcriptional regulator). These 3 isolates demonstrated no evidence of functional antiviral resistance when IC50 was assessed. Most (10/14 pairs) day 1 and 8 viral isolate pairs from the same host animal were near-identical. While functional variants were not detected in this small sample, these techniques can be replicated to assess FHV-1 isolates suspected of having developed resistance to antiviral medications.
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2
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Birkmann A, Bonsmann S, Kropeit D, Pfaff T, Rangaraju M, Sumner M, Timmler B, Zimmermann H, Buschmann H, Ruebsamen-Schaeff H. Discovery, Chemistry, and Preclinical Development of Pritelivir, a Novel Treatment Option for Acyclovir-Resistant Herpes Simplex Virus Infections. J Med Chem 2022; 65:13614-13628. [PMID: 36202389 PMCID: PMC9620171 DOI: 10.1021/acs.jmedchem.2c00668] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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When the nucleoside analogue acyclovir was introduced
in the early
1980s, it presented a game-changing treatment modality for herpes
simplex virus infections. Since then, work has been ongoing to improve
the weaknesses that have now been identified: a narrow time window
for therapeutic success, resistance in immunocompromised patients,
little influence on frequency of recurrences, relatively fast elimination,
and poor bioavailability. The present Drug Annotation focuses on the
helicase–primase inhibitor pritelivir currently in development
for the treatment of acyclovir-resistant HSV infections and describes
how a change of the molecular target (from viral DNA polymerase to
the HSV helicase–primase complex) afforded improvement of the
shortcomings of nucleoside analogs. Details are presented for the
discovery process leading to the final drug candidate, the pivotal
preclinical studies on mechanism of action and efficacy, and on how
ongoing clinical research has been able to translate preclinical promises
into clinical use.
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Affiliation(s)
| | | | - Dirk Kropeit
- AiCuris Anti-Infective Cures AG, 42117 Wuppertal, Germany
| | - Tamara Pfaff
- AiCuris Anti-Infective Cures AG, 42117 Wuppertal, Germany
| | | | - Melanie Sumner
- AiCuris Anti-Infective Cures AG, 42117 Wuppertal, Germany
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Roy S, Sukla S, De A, Biswas S. Non-cytopathic herpes simplex virus type-1 isolated from acyclovir-treated patients with recurrent infections. Sci Rep 2022; 12:1345. [PMID: 35079057 PMCID: PMC8789845 DOI: 10.1038/s41598-022-05188-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 01/05/2022] [Indexed: 11/09/2022] Open
Abstract
Herpes simplex virus (HSV) usually produces cytopathic effect (CPE) within 24-72 h post-infection (P.I.). Clinical isolates from recurrent HSV infections in patients on Acyclovir therapy were collected between 2016 and 2019 and tested in cell cultures for cytopathic effects and further in-depth characterization. Fourteen such isolates did not show any CPE in A549 or Vero cell lines even at 120 h P.I. However, these cultures remained positive for HSV-DNA after several passages. Sequence analysis revealed that the non-CPE isolates were all HSV-1. Analysis of the thymidine kinase gene from the isolates revealed several previously reported and two novel ACV-resistant mutations. Immunofluorescence and Western blot data revealed a low-level expression of the immediate early protein, ICP4. Late proteins like ICP5 or capsid protein, VP16 were almost undetectable in these isolates. AFM imaging revealed that the non-CPE viruses had structural deformities compared to wild-type HSV-1. Our findings suggest that these strains are manifesting an unusual phenomenon of being non-CPE herpesviruses with low level of virus protein expressions over several passages. Probably these HSV-1 isolates are evolving towards a more "cryptic" form to establish chronic infection in the host thereby unraveling yet another strategy of herpesviruses to evade the host immune system.
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Affiliation(s)
- Subrata Roy
- Infectious Diseases and Immunology Division, CSIR- Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, West Bengal, 700032, India
| | - Soumi Sukla
- Infectious Diseases and Immunology Division, CSIR- Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, West Bengal, 700032, India
- Department of Pharmacology and Toxicology, National Institute of Pharmaceuticals Education and Research, 168, Maniktala Main Road, Kolkata, West Bengal, India
| | - Abhishek De
- Department of Dermatology, Calcutta National Medical College and Hospital, Kolkata, West Bengal, India
| | - Subhajit Biswas
- Infectious Diseases and Immunology Division, CSIR- Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, West Bengal, 700032, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India.
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4
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High conservation of varicella-zoster virus helicase-primase complex, the target of the new antiviral drug amenamevir. Antiviral Res 2021; 195:105189. [PMID: 34666108 DOI: 10.1016/j.antiviral.2021.105189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/08/2021] [Accepted: 10/15/2021] [Indexed: 11/23/2022]
Abstract
Varicella-zoster virus (VZV) resistance to current antiviral drugs, that all target the viral DNA polymerase, represents a growing concern, notably among immunocompromised patients. Amenamevir, a novel antiviral that inhibits the VZV helicase-primase (HP) complex, is approved in Japan for the treatment of herpes zoster. In this study, we describe the low natural polymorphism of VZV HP complex (interstrain identity >99.7% both at nucleotide and amino acid levels) among 44 VZV clinical isolates. This work enabled to settle the maps of natural polymorphisms of VZV HP complex and to provide the genotypic tools for the monitoring of the emergence of VZV resistance to amenamevir in patients.
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Piret J, Boivin G. Antiviral Drugs Against Herpesviruses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1322:1-30. [PMID: 34258735 DOI: 10.1007/978-981-16-0267-2_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The discovery of the nucleoside analogue, acyclovir, represented a milestone in the management of infections caused by herpes simplex virus and varicella-zoster virus. Ganciclovir, another nucleoside analogue, was then used for the management of systemic and organ-specific human cytomegalovirus diseases. The pyrophosphate analogue, foscarnet, and the nucleotide analogue, cidofovir, have been approved subsequently and constitute the second-line antiviral drugs. However, the viral DNA polymerase is the ultimate target of all these antiviral agents with a possible emergence of cross-resistance between these drugs. Recently, letermovir that targets the viral terminase complex was approved for the prophylaxis of human cytomegalovirus infections in hematopoietic stem cell transplant recipients. Other viral targets such as the protein kinase and the helicase-primase complex are also evaluated for the development of novel potent inhibitors against herpesviruses.
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Affiliation(s)
| | - Guy Boivin
- CHU de Québec-Laval University, Quebec City, QC, Canada.
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6
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Topalis D, Gillemot S, Snoeck R, Andrei G. Thymidine kinase and protein kinase in drug-resistant herpesviruses: Heads of a Lernaean Hydra. Drug Resist Updat 2018; 37:1-16. [PMID: 29548479 DOI: 10.1016/j.drup.2018.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Herpesviruses thymidine kinase (TK) and protein kinase (PK) allow the activation of nucleoside analogues used in anti-herpesvirus treatments. Mutations emerging in these two genes often lead to emergence of drug-resistant strains responsible for life-threatening diseases in immunocompromised populations. In this review, we analyze the binding of different nucleoside analogues to the TK active site of the three α-herpesviruses [Herpes Simplex Virus 1 and 2 (HSV-1 and HSV-2) and Varicella-Zoster Virus (VZV)] and present the impact of known mutations on the structure of the viral TKs. Furthermore, models of β-herpesviruses [Human cytomegalovirus (HCMV) and human herpesvirus-6 (HHV-6)] PKs allow to link amino acid changes with resistance to ganciclovir and/or maribavir, an investigational chemotherapeutic used in patients with multidrug-resistant HCMV. Finally, we set the basis for the understanding of drug-resistance in γ-herpesviruses [Epstein-Barr virus (EBV) and Kaposi's sarcoma associated herpesvirus (KSHV)] TK and PK through the use of animal surrogate models.
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Affiliation(s)
- Dimitri Topalis
- Rega Institute for Medical Research, KU Leuven, Herestraat 49-box 1043, 3000 Leuven, Belgium.
| | - Sarah Gillemot
- Rega Institute for Medical Research, KU Leuven, Herestraat 49-box 1043, 3000 Leuven, Belgium.
| | - Robert Snoeck
- Rega Institute for Medical Research, KU Leuven, Herestraat 49-box 1043, 3000 Leuven, Belgium.
| | - Graciela Andrei
- Rega Institute for Medical Research, KU Leuven, Herestraat 49-box 1043, 3000 Leuven, Belgium.
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Abstract
PURPOSE OF REVIEW The mainstay of antiviral therapy for the alpha-herpesviruses [herpes simplex virus (HSV)-1, HSV-2, and varicella zoster virus (VZV)] over the past 40 years has been the nucleoside analogues such as aciclovir. Although conventional antiviral therapy has reduced mortality in severe disease, novel agents are needed to address the emergence of resistance and toxicity associated with current second-line therapy. Treatment and prophylaxis of VZV and HSV reactivations remains a challenge. RECENT FINDINGS A number of compounds have recently been evaluated in human clinical trials, amongst them brincidofovir, an intracellularly acting derivative of cidofovir currently undergoing phase III trials. The helicase-primase inhibitors are a new class of antiviral agent and may circumvent resistance to existing agents. Amenamevir and pritelivir are two examples of these agents that have been evaluated clinically along with novel nucleoside analogues such as valomaciclovir and FV-100. Tenofovir, an agent used in HIV and hepatitis B therapy, may also have a role in the prevention of HSV-2 acquisition and reduce viral shedding. SUMMARY Although several novel antiviral agents have undergone clinical trials in recent years, all are yet to gain licensure. Brincidofovir appears to be the candidate with most promise for adoption into routine practice in the near future.
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8
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Edlefsen PT, Birkmann A, Huang ML, Magaret CA, Kee JJ, Diem K, Goldner T, Timmler B, Stoelben S, Ruebsamen-Schaeff H, Zimmermann H, Warren T, Wald A, Corey L. No Evidence of Pritelivir Resistance Among Herpes Simplex Virus Type 2 Isolates After 4 Weeks of Daily Therapy. J Infect Dis 2016; 214:258-64. [PMID: 27056950 PMCID: PMC4918824 DOI: 10.1093/infdis/jiw129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 03/24/2016] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Pritelivir is a novel helicase-primase inhibitor in clinical development for treatment of herpes simplex virus type 2 (HSV-2) infections. In preclinical work, resistance-mediating mutations were identified in the HSV-2 genome at 3 loci in the UL5 gene and 1 locus in UL52. METHODS To evaluate whether daily pritelivir treatment results in emergence of resistance-mediating mutations, we analyzed HSV-2 strains detected in genital swab specimens from trial participants who were randomly assigned to receive different dosages of pritelivir. We sequenced resistance regions from 87 participants' samples, the UL5 gene in 73 samples from 44 participants, and the UL52 gene in 71 samples from 43 participants. RESULTS We found no evidence that pritelivir induced known resistance-mediating mutations or for amino acid variation at other loci. In one participant's HSV-2 isolate, we found a previously unidentified mutation close to the putative resistance-mediating region in UL5 and subsequently determined in vitro susceptibility to pritelivir. We characterized mutations from 32 cultivated HSV-2 isolates previously found to be susceptible to pritelivir in vitro and identified several novel mutations that most likely reflect preexisting variation in circulating HSV-2. CONCLUSIONS This study demonstrates evidence of retained susceptibility of HSV-2 to pritelivir in immunocompetent persons following daily therapy for up to 28 days.
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Affiliation(s)
- Paul T Edlefsen
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Biostatistics
| | | | - Meei-Li Huang
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Laboratory Medicine
| | - Craig A Magaret
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center
| | - Jia Jin Kee
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Biostatistics
| | - Kurt Diem
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Laboratory Medicine
| | | | | | | | | | | | | | - Anna Wald
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Laboratory Medicine Department of Epidemiology Department of Medicine, University of Washington, Seattle
| | - Lawrence Corey
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center Department of Laboratory Medicine Department of Medicine, University of Washington, Seattle
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9
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Collot M, Rouard C, Brunet C, Agut H, Boutolleau D, Burrel S. High conservation of herpes simplex virus UL5/UL52 helicase-primase complex in the era of new antiviral therapies. Antiviral Res 2016; 128:1-6. [PMID: 26826441 DOI: 10.1016/j.antiviral.2016.01.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/13/2016] [Accepted: 01/22/2016] [Indexed: 10/22/2022]
Abstract
The emergence of herpes simplex virus (HSV) resistance to current antiviral drugs, that all target the viral DNA polymerase, constitutes a major obstacle to antiviral treatment effectiveness of HSV infections, especially in immunocompromised patients. A novel and promising class of inhibitors of the HSV UL5/UL52 helicase-primase (HP) complex has been reported to hinder viral replication with a high potency. In this study, we describe the low natural polymorphism (interstrain identity >99.1% at both nucleotide and amino acid levels) of HSV HP complex subunits pUL5 and pUL52 among 64 HSV (32 HSV-1 and 32 HSV-2) clinical isolates, and we show that the HSV resistance profile to the first-line antiviral drug acyclovir (ACV) does not impact on the natural polymorphism of HSV HP complex. Genotypic tools and polymorphism data concerning HSV HP complex provided herein will be useful to detect drug resistance mutations in a relevant time frame when HP inhibitors (HPIs), i.e., amenamevir and pritelivir, will be available in medical practice.
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Affiliation(s)
- Marianne Collot
- Centre Hospitalier et Universitaire de Nantes, Service de Virologie, Nantes, France; EA4271 « Immunovirology and Genetic Polymorphism », Université de Nantes, France
| | - Caroline Rouard
- AP-HP, Hôpital Universitaire Antoine Béclère, Service de Microbiologie, Clamart, France; EA4043 - Unité Bactéries Pathogènes et Santé UFR de Pharmacie-Université Paris-Sud, France
| | - Christel Brunet
- AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière-Charles Foix, Service de Virologie, Paris, France
| | - Henri Agut
- AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière-Charles Foix, Service de Virologie, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), INSERM U1135, Paris, France
| | - David Boutolleau
- AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière-Charles Foix, Service de Virologie, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), INSERM U1135, Paris, France
| | - Sonia Burrel
- AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière-Charles Foix, Service de Virologie, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), INSERM U1135, Paris, France.
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10
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Helicase–primase inhibitors for herpes simplex virus: looking to the future of non-nucleoside inhibitors for treating herpes virus infections. Future Med Chem 2014; 6:45-55. [DOI: 10.4155/fmc.13.192] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Helicase–primase inhibitors (HPIs) are the first new family of potent herpes virus (herpes simplex and varicella-zoster virus) inhibitors to go beyond the preliminary stages of investigation since the emergence of the original nucleoside analog inhibitors. To consider the clinical future of HPIs, this review puts the exciting new findings with two HPIs, amenamevir and pritelivir, into the historical context of antiviral development for the prevention and treatment of herpes simplex virus over the last century and, on this basis, the authors speculate on the potential evolution of these and other non-nucleoside inhibitors in the future.
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11
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Field HJ, Huang ML, Lay EM, Mickleburgh I, Zimmermann H, Birkmann A. Baseline sensitivity of HSV-1 and HSV-2 clinical isolates and defined acyclovir-resistant strains to the helicase–primase inhibitor pritelivir. Antiviral Res 2013; 100:297-9. [DOI: 10.1016/j.antiviral.2013.08.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 11/25/2022]
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12
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De Clercq E. Dancing with chemical formulae of antivirals: A panoramic view (Part 2). Biochem Pharmacol 2013; 86:1397-410. [DOI: 10.1016/j.bcp.2013.09.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 09/12/2013] [Accepted: 09/12/2013] [Indexed: 12/11/2022]
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13
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Shadrick WR, Ndjomou J, Kolli R, Mukherjee S, Hanson AM, Frick DN. Discovering new medicines targeting helicases: challenges and recent progress. ACTA ACUST UNITED AC 2013; 18:761-81. [PMID: 23536547 PMCID: PMC4427233 DOI: 10.1177/1087057113482586] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Helicases are ubiquitous motor proteins that separate and/or rearrange nucleic acid duplexes in reactions fueled by adenosine triphosphate (ATP) hydrolysis. Helicases encoded by bacteria, viruses, and human cells are widely studied targets for new antiviral, antibiotic, and anticancer drugs. This review summarizes the biochemistry of frequently targeted helicases. These proteins include viral enzymes from herpes simplex virus, papillomaviruses, polyomaviruses, coronaviruses, the hepatitis C virus, and various flaviviruses. Bacterial targets examined include DnaB-like and RecBCD-like helicases. The human DEAD-box protein DDX3 is the cellular antiviral target discussed, and cellular anticancer drug targets discussed are the human RecQ-like helicases and eIF4A. We also review assays used for helicase inhibitor discovery and the most promising and common helicase inhibitor chemotypes, such as nucleotide analogues, polyphenyls, metal ion chelators, flavones, polycyclic aromatic polymers, coumarins, and various DNA binding pharmacophores. Also discussed are common complications encountered while searching for potent helicase inhibitors and possible solutions for these problems.
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Affiliation(s)
- William R Shadrick
- Department of Chemistry & Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
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14
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De Clercq E. A cutting-edge view on the current state of antiviral drug development. Med Res Rev 2013; 33:1249-77. [PMID: 23495004 DOI: 10.1002/med.21281] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Prominent in the current stage of antiviral drug development are: (i) for human immunodeficiency virus (HIV), the use of fixed-dose combinations (FDCs), the most recent example being Stribild(TM); (ii) for hepatitis C virus (HCV), the pleiade of direct-acting antivirals (DAAs) that should be formulated in the most appropriate combinations so as to obtain a cure of the infection; (iii)-(v) new strategies (i.e., AIC316, AIC246, and FV-100) for the treatment of herpesvirus infections: herpes simplex virus (HSV), cytomegalovirus (CMV), and varicella-zoster virus (VZV), respectively; (vi) the role of a new tenofovir prodrug, tenofovir alafenamide (TAF) (GS-7340) for the treatment of HIV infections; (vii) the potential use of poxvirus inhibitors (CMX001 and ST-246); (viii) the usefulness of new influenza virus inhibitors (peramivir and laninamivir octanoate); (ix) the position of the hepatitis B virus (HBV) inhibitors [lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate (TDF)]; and (x) the potential of new compounds such as FGI-103, FGI-104, FGI-106, dUY11, and LJ-001 for the treatment of filoviruses (i.e., Ebola). Whereas for HIV and HCV therapy is aimed at multiple-drug combinations, for all other viruses, HSV, CMV, VZV, pox, influenza, HBV, and filoviruses, current strategies are based on the use of single compounds.
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, KU Leuven, B-3000, Leuven, Belgium.
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15
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De Clercq E. Selective anti-herpesvirus agents. Antivir Chem Chemother 2013; 23:93-101. [PMID: 23343513 DOI: 10.3851/imp2533] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/24/2012] [Indexed: 10/27/2022] Open
Abstract
This review article focuses on the anti-herpesvirus agents effective against herpes simplex virus, varicella-zoster virus and cytomegalovirus, which have either been licensed for clinical use (idoxuridine, trifluridine, brivudin, acyclovir, valaciclovir, valganciclovir, famciclovir and foscarnet) or are under clinical development (CMX001 [the hexadecyloxypropyl prodrug of cidofovir], the helicase-primase inhibitor BAY 57-1293 [now referred to as AIC316], FV-100 [the valine ester of Cf 1743] and the terminase inhibitor letermovir [AIC246]).
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, KU Leuven, Leuven, Belgium.
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16
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Field HJ, Mickleburgh I. The helicase-primase complex as a target for effective herpesvirus antivirals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 767:145-59. [PMID: 23161010 DOI: 10.1007/978-1-4614-5037-5_7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Herpes simplex virus and varicella-zoster virus have been treated for more that half a century using nucleoside analogues. However, there is still an unmet clinical need for improved herpes antivirals. The successful compounds, acyclovir; penciclovir and their orally bioavailable prodrugs valaciclovir and famciclovir, ultimately block virus replication by inhibiting virus-specific DNA-polymerase. The helicase-primase (HP) complex offers a distinctly different target for specific inhibition of virus DNA synthesis. This review describes the synthetic programmes that have already led to two HP-inhibitors (HPI) that have commenced clinical trials in man. One of these (known as AIC 316) continues in clinical development to date. The specificity of HPI is reflected by the ability to select drug-resistant mutants. The role of HP-antiviral resistance will be considered and how the study of cross--resistance among mutants already shows subtle differences between compounds in this respect. The impact of resistance on the drug development in the clinic will also be considered. Finally, herpesvirus latency remains as the most important barrier to a therapeutic cure. Whether or not helicase primase inhibitors alone or in combination with nucleoside analogues can impact on this elusive goal remains to be seen.
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17
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De Clercq E. Human viral diseases: what is next for antiviral drug discovery? Curr Opin Virol 2012; 2:572-9. [PMID: 22846888 DOI: 10.1016/j.coviro.2012.07.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 07/10/2012] [Indexed: 01/30/2023]
Abstract
For the treatment of human immunodeficiency virus (HIV) infections for which there are ample drugs available, the immediate future lies in a once-daily combination pill containing three or four active ingredients. This strategy may also be envisaged for the treatment of hepatitis C virus (HCV) infections as soon as we have at hand the appropriate direct-acting antiviral agents (DAAs) to be combined. A combination drug therapy is generally not entertained for other viruses. Yet, new drugs are at the horizon for the treatment of herpes simplex virus (HSV), varicella-zoster virus (VZV), poxvirus, hepatitis B virus (HBV), influenza and enveloped viruses-at-large.
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium.
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18
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Susceptibility of herpes simplex virus isolated from genital herpes lesions to ASP2151, a novel helicase-primase inhibitor. Antimicrob Agents Chemother 2012; 56:3587-91. [PMID: 22526302 DOI: 10.1128/aac.00133-12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ASP2151 (amenamevir) is a helicase-primase inhibitor against herpes simplex virus type 1 (HSV-1), HSV-2, and varicella-zoster virus. To evaluate the anti-HSV activity of ASP2151, susceptibility testing was performed on viruses isolated from patients participating in a placebo- and valacyclovir-controlled proof-of-concept phase II study for recurrent genital herpes. A total of 156 HSV strains were isolated prior to the dosing of patients, and no preexisting variants with less susceptibility to ASP2151 or acyclovir (ACV) were detected. ASP2151 inhibited HSV-1 and HSV-2 replication with mean 50% effective concentrations (EC(50)s) of 0.043 and 0.069 μM, whereas ACV exhibited mean EC(50)s of 2.1 and 3.2 μM, respectively. Notably, the susceptibilities of HSV isolates to ASP2151 and ACV were not altered after dosing with the antiviral agents. Taken together, these results demonstrate that ASP2151 inhibits the replication of HSV clinical isolates more potently than ACV, and HSV resistant to this novel helicase-primase inhibitor as well as ACV may not easily emerge in short-term treatment for recurrent genital herpes patients.
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Birkmann A, Hewlett G, Rübsamen-Schaeff H, Zimmermann H. Helicase–primase inhibitors as the potential next generation of highly active drugs against herpes simplex viruses. Future Virol 2011. [DOI: 10.2217/fvl.11.28] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Since the introduction of the nucleoside analogs decades ago, treatment of herpes simplex virus (HSV) infections has not seen much innovation, except for the development of their respective prodrugs. The inhibitors of the helicase–primase complex of HSV represent a very innovative approach to the treatment of herpesvirus disease, and this article considers the development of some representatives of this class of therapeutics. The molecular and biochemical features of the helicase–primase complex are considered and the development of three inhibitors of helicase–primase, BILS 179 BS, AIC316 and ASP2151, is described. The clinical development of AIC316 is at an advanced stage and displays general safety as well as favorable, long-lasting exposures in healthy volunteers. The first efficacy data from a Phase II trial with more than 150 HSV-2-positive subjects demonstrated dose-dependent antiviral activity.
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Affiliation(s)
- Alexander Birkmann
- AiCuris GmbH & Co. KG, Friedrich-Ebert-Str. 475, 42117 Wuppertal, Germany
| | - Guy Hewlett
- hbsc, Thienhausener Str. 37, 42781 Haan, Germany
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Biswas S, Field HJ. Helicase-Primase Inhibitors: A New Approach to Combat Herpes Simplex Virus and Varicella Zoster Virus. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/9783527635955.ch6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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21
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Inhibition of bovine viral diarrhea virus RNA synthesis by thiosemicarbazone derived from 5,6-dimethoxy-1-indanone. J Virol 2011; 85:5436-45. [PMID: 21430053 DOI: 10.1128/jvi.00859-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In the present work, we described the activity of the thiosemicarbazone derived from 5,6-dimethoxy-1-indanone (TSC), which we previously characterized as a new compound that inhibits bovine viral diarrhea virus (BVDV) infection. We showed that TSC acts at a point of time that coincides with the onset of viral RNA synthesis and that it inhibits the activity of BVDV replication complexes (RCs). Moreover, we have selected five BVDV mutants that turned out to be highly resistant to TSC but still susceptible to ribavirin (RBV). Four of these resistant mutants carried an N264D mutation in the viral RNA-dependent RNA polymerase (RdRp). The remaining mutant showed an A392E mutation within the same protein. Some of these mutants replicated slower than the wild-type (wt) virus in the absence of TSC, whereas others showed a partial reversion to the wt phenotype over several passages in the absence of the compound. The docking of TSC in the crystal structure of the BVDV RdRp revealed a close contact between the indane ring of the compound and several residues within the fingers domain of the enzyme, some hydrophobic contacts, and hydrogen bonds with the thiosemicarbazone group. Finally, in the mutated RdRp from resistant BVDV, these interactions with TSC could not be achieved. Interestingly, TSC inhibited BVDV replication in cell culture synergistically with RBV. In conclusion, TSC emerges as a new nonnucleoside inhibitor of BVDV RdRp that is synergistic with RBV, a feature that turns it into a potential compound to be evaluated against hepatitis C virus (HCV).
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Abstract
This chapter discusses the general mechanisms of antiviral resistance. Mammalian viruses represent a diverse group of infectious agents. The viruses that cause the common diseases of man and domestic animals comprise approximately 25 known families, which fall into groups according to their genome and replication strategies. Further evolution of modern viruses is continuing with mutations, recombinations, or reassortments. The use of vaccines has greatly reduced the burden of human disease caused by several other human viruses. Specific antiviral compounds have been developed for several of those viral infections that have not been adequately controlled by vaccines. Herpes viruses establish a latent state that enables the virus to remain in the host for a lifetime despite normal adaptive immune responses. Antivirals are effective at reducing virus replication during an acute episode. Another way in which a virus can establish a form of latency is by means of integration of a DNA copy of the genome. The virus has over 100 serotypes/genotypes. The mutation rate of a virus has been described as the probability that during a single replication of the virus genome a particular nucleotide position is altered. Several families of RNA virus have segmented genomes. Resistant variants are selected so quickly that a treated person can pass on resistant virus to contacts. Viruses are resistant to specific antiviral drugs. Although the genetic barrier needs to be increased for long-term delay in resistance in chronic infections, with any drug combination used in naturally self-limiting infections, the extra effect in reducing viral load quickly may well be a useful benefit. Our current antiviral therapies have been successful in reducing the burden of human diseases but many viruses have evolved strategies for countering new threats to their replication.
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Field HJ, Biswas S. Antiviral drug resistance and helicase-primase inhibitors of herpes simplex virus. Drug Resist Updat 2010; 14:45-51. [PMID: 21183396 DOI: 10.1016/j.drup.2010.11.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 11/22/2010] [Accepted: 11/23/2010] [Indexed: 11/17/2022]
Abstract
A new class of chemical inhibitors has been discovered that interferes with the process of herpesvirus DNA replication. To date, the majority of useful herpesvirus antivirals are nucleoside analogues that block herpesvirus DNA replication by targeting the DNA polymerase. The new helicase-primase inhibitors (HPI) target a different enzyme complex that is also essential for herpesvirus DNA replication. This review will place the HPI in the context of previous work on the nucleoside analogues. Several promising highly potent HPI will be described with a particular focus on the identification of drug-resistance mutations. Several HPI have good pharmacological profiles and are now at the outset of phase II clinical trials. Provided there are no safety issues to stop their progress, this new class of compound will be a major advance in the herpesvirus antiviral field. Furthermore, HPI are likely to have a major impact on the therapy and prevention of herpes simplex virus and varicella zoster in both immunocompetent and immunocompromised patients alone or in combination with current nucleoside analogues. The possibility of acquired drug-resistance to HPI will then become an issue of great practical importance.
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Affiliation(s)
- Hugh J Field
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB30ES, United Kingdom.
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Sukla S, Biswas S, Birkmann A, Lischka P, Zimmermann H, Field HJ. Mismatch primer-based PCR reveals that helicase-primase inhibitor resistance mutations pre-exist in herpes simplex virus type 1 clinical isolates and are not induced during incubation with the inhibitor. J Antimicrob Chemother 2010; 65:1347-52. [PMID: 20453068 DOI: 10.1093/jac/dkq135] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES Previous studies suggested that helicase-primase inhibitor (HPI) resistance mutations can be selected at relatively high frequency from some isolates of herpes simplex virus type 1 (HSV-1). An intentional mismatch primer (IMP) PCR was developed to detect three known HPI resistance mutations well above the expected background frequency. The objective of this study was to provide proof that HPI resistance mutations pre-exist at relatively high frequency in some clinical isolates obtained from individuals naive to HPIs. METHODS Three different IMP PCRs were standardized to detect critical HPI resistance mutations (K356N or K356T in UL5, or A899T in UL52) at 10-100 times the expected background frequency (<10(-6)). Thirty HSV-1 clinical isolates were then screened for the resistance mutations in the absence of the inhibitor using IMP PCR. RESULTS Among 30 clinical isolates that were all susceptible to the HPI, BAY 57-1293, 5 were shown to contain UL5 mutations at 10-100 times higher than the expected frequency. No UL52 resistance mutations were encountered in this study. CONCLUSIONS The detection of HPI-resistant mutations in some clinical isolates by means of IMP PCR proved that the mutations pre-exist and showed that they are not induced during incubation with the inhibitor.
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Affiliation(s)
- Soumi Sukla
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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Sukla S, Biswas S, Birkmann A, Lischka P, Ruebsamen-Schaeff H, Zimmermann H, Field HJ. Effects of therapy using a helicase-primase inhibitor (HPI) in mice infected with deliberate mixtures of wild-type HSV-1 and an HPI-resistant UL5 mutant. Antiviral Res 2010; 87:67-73. [PMID: 20420855 DOI: 10.1016/j.antiviral.2010.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Revised: 04/19/2010] [Accepted: 04/20/2010] [Indexed: 10/19/2022]
Abstract
Point mutations in the HSV-1 UL5 (helicase) gene confer resistance to helicase-primase inhibitors (HPIs), e.g. BAY 57-1293. Such mutations normally occur at a frequency of < or =10(-6)PFU. However, individual HSV-1 laboratory strains and some clinical isolates contained resistance mutations (e.g. UL5: Lys356Asn) at 10(-4)PFU. To address the possibility that pre-existing mutants at high frequency might have an impact on therapy using HPIs, deliberate mixtures were prepared to contain the SC16 UL5: Lys356Asn mutant in SC16 wild-type in the proportion of 1/500 or 1/50PFU. Mice were infected in the neck-skin with 5x10(4)PFU/mouse of wt alone, mutant alone, or the respective mixture. The mutant could not be detected in infectious virus yields from mice inoculated with the 1/500 mixture. However, resistant mutant was recovered from some treated mice inoculated with the 1/50 mixture. All mice inoculated with mixtures remained responsive to BAY 57-1293-therapy with no increase in clinical signs compared to treatment of wt-infected mice.
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Affiliation(s)
- Soumi Sukla
- Department of Veterinary Medicine, University of Cambridge, United Kingdom
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Wilson SS, Fakioglu E, Herold BC. Novel approaches in fighting herpes simplex virus infections. Expert Rev Anti Infect Ther 2009; 7:559-68. [PMID: 19485796 DOI: 10.1586/eri.09.34] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The development of novel strategies to eradicate herpes simplex virus (HSV) is a global public health priority. While acyclovir and related nucleoside analogues provide successful modalities for treatment and suppression, HSV remains highly prevalent worldwide and is a major cofactor fueling the HIV epidemic. HSV is the predominant cause of genital ulcerative disease, and neonatal and sporadic infectious encephalitis. Asymptomatic shedding, which occurs more frequently than previously appreciated, contributes to viral transmission. Acyclovir resistance may be problematic for immunocompromised patients and highlights the need for new safe and effective agents. Ideally, vaccines to prevent infection, drugs to inhibit the establishment of or reactivation from latency, or vaginal microbicides to prevent sexual and perinatal transmission are needed to control the epidemic. This review summarizes current therapeutic options and strategies in development.
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Affiliation(s)
- Sarah S Wilson
- Department of Pediatrics, Albert Einstein College of Medicine, Forchheimer 702, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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Biswas S, Miguel RN, Sukla S, Field HJ. A mutation in helicase motif IV of herpes simplex virus type 1 UL5 that results in reduced growth in vitro and lower virulence in a murine infection model is related to the predicted helicase structure. J Gen Virol 2009; 90:1937-1942. [PMID: 19403757 DOI: 10.1099/vir.0.011221-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A variant was selected from a clinical isolate of herpes simplex virus type 1 (HSV-1) during a single passage in the presence of a helicase-primase inhibitor (HPI) at eight times the IC(50). The variant was approximately 40-fold resistant to the HPI BAY 57-1293 and it showed significantly reduced growth in tissue culture with a concomitant reduction in virulence in a murine infection model. The variant contained a single mutation (Asn342Lys) in the UL5 predicted functional helicase motif IV. The Asn342Lys mutation was transferred to a laboratory strain, PDK cl-1, and the recombinant acquired the expected resistance and reduced growth characteristics. Comparative modelling and docking studies predicted the Asn342 position to be physically distant from the HPI interaction pocket formed by UL5 and UL52 (primase). We suggest that this mutation results in steric/allosteric modification of the HPI-binding pocket, conferring an indirect resistance to the HPI. Slower growth and moderately reduced virulence suggest that this mutation might also interfere with the helicase-primase activity.
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Affiliation(s)
- Subhajit Biswas
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | | | - Soumi Sukla
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Hugh J Field
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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Biswas S, Field HJ. Herpes simplex virus helicase-primase inhibitors: recent findings from the study of drug resistance mutations. Antivir Chem Chemother 2008; 19:1-6. [PMID: 18610552 DOI: 10.1177/095632020801900101] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
After several decades during which nucleoside analogues (especially acyclovir and penciclovir and their prodrugs) have benefited many patients suffering from herpes simplex virus (HSV) infections, the discovery of the helicase-primase inhibitors (HPIs) represents an interesting new approach. Although antiviral resistance has not been a major problem for nucleoside analogues in immunocompetent patients, the problem of acyclovir resistance in immunocompromised patients is well documented. Several HPIs are extremely potent antiviral compounds and may, therefore, offer an important alternative therapy in these patients. The potential for synergy, not just for the inhibition of virus replication but also to delay the appearance of drug-resistant virus, needs to be thoroughly investigated. The study of resistance to HPIs has been important towards understanding the mechanism of action of these compounds and confirming the target function. However, during the course of our studies on HPI resistance, we have made a number of interesting observations that may be relevant to their clinical use. This article draws attention to the major observations on HPI resistance reported by others and to our own recently published observations that have extended this expanding area of antiviral research.
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Affiliation(s)
- Subhajit Biswas
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
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30
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Abstract
Most of the antiviral agents that have been approved, and are currently used in the treatment of virus infections, are targeted at HIV, HBV, herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV) and HCV or influenza virus. Additional compounds for HIV, HBV, HSV, VZV, CMV, HCV, influenza virus and several other viral infections, for example poxvirus (e.g., variola, vaccinia and monkeypox), respiratory syncytial virus, hemorrhagic fever virus (e.g., Lassa, Rift Valley and Ebola) and enterovirus (e.g., polio, Coxsackie and echo), are still in the experimental stage, that is, under clinical or preclinical development.
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium
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Mutations close to functional motif IV in HSV-1 UL5 helicase that confer resistance to HSV helicase-primase inhibitors, variously affect virus growth rate and pathogenicity. Antiviral Res 2008; 80:81-5. [PMID: 18539344 DOI: 10.1016/j.antiviral.2008.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 04/12/2008] [Accepted: 04/15/2008] [Indexed: 11/23/2022]
Abstract
Herpes simplex virus (HSV) helicase-primase (HP) is the target for a novel class of antiviral compounds, the helicase-primase inhibitors (HPIs), e.g. BAY 57-1293. Although mutations in herpesviruses conferring resistance to nucleoside analogues are commonly associated with attenuation in vivo, to date, this is not necessarily true for HPIs. HPI-resistant HSV mutants selected in tissue culture are reported to be equally pathogenic compared to parental virus in animal models. Here we demonstrate that a slow-growing HSV-1 mutant, with the BAY 57-1293-resistance mutation Gly352Arg in UL5 helicase, is clearly less virulent than its wild-type parent in a murine zosteriform infection model. This contrasts with published results obtained for a mutant containing a different HPI-resistance substitution (Gly352Val) at the same location, since this mutant was reported to be fully pathogenic. We believe our report to be the first to describe an HPI-resistant HSV-1 mutant, that is markedly less virulent in vivo and slowly growing in tissue culture compared to the parental strain. Another BAY 57-1293-resistant UL5 mutant (Lys356Gln), which showed faster growth characteristics in cell culture, however, was at least equally virulent compared to the parent strain.
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A single drug-resistance mutation in HSV-1 UL52 primase points to a difference between two helicase–primase inhibitors in their mode of interaction with the antiviral target. J Antimicrob Chemother 2008; 61:1044-7. [DOI: 10.1093/jac/dkn057] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Shankar J, Tuteja R. UvrD helicase of Plasmodium falciparum. Gene 2007; 410:223-33. [PMID: 18242886 DOI: 10.1016/j.gene.2007.12.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Revised: 12/04/2007] [Accepted: 12/13/2007] [Indexed: 11/25/2022]
Abstract
Malaria caused by the mosquito-transmitted parasite Plasmodium is the cause of enormous number of deaths every year in the tropical and subtropical areas of the world. Among four species of Plasmodium, Plasmodium falciparum causes most fatal form of malaria. With time, the parasite has developed insecticide and drug resistance. Newer strategies and advent of novel drug targets are required so as to combat the deadly form of malaria. Helicases is one such class of enzymes which has previously been suggested as potential antiviral and anticancer targets. These enzymes play an essential role in nearly all the nucleic acid metabolic processes, catalyzing the transient opening of the duplex nucleic acids in an NTP-dependent manner. DNA helicases from the PcrA/UvrD/Rep subfamily are important for the survival of the various organisms. Members from this subfamily can be targeted and inhibited by a variety of synthetic compounds. UvrD from this subfamily is the only member present in the P. falciparum genome, which shows no homology with UvrD from human and thus can be considered as a strong potential drug target. In this manuscript we provide an overview of UvrD family of helicases and bioinformatics analysis of UvrD from P. falciparum.
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Affiliation(s)
- Jay Shankar
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067, India
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