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Nevrlka F, Bědroň A, Valenta M, Tranová L, Stýskala J. Study of Direct N7 Regioselective tert-Alkylation of 6-Substituted Purines and Their Modification at Position C6 through O, S, N, and C Substituents. ACS OMEGA 2024; 9:17368-17378. [PMID: 38645315 PMCID: PMC11024948 DOI: 10.1021/acsomega.4c00068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 02/26/2024] [Accepted: 03/27/2024] [Indexed: 04/23/2024]
Abstract
A new N7 direct regioselective method allowing the introduction of tert-alkyl groups into appropriate 6-substituted purine derivatives is developed. This method is based on a reaction of N-trimethylsilylated purines with a tert-alkyl halide using SnCl4 as a catalyst. In this work, we study the structure and optimal reaction conditions leading to the N7 isomer and in some cases also to the N9 isomer. The main goal is devoted to preparing 7-(tert-butyl)-6-chloropurine as a suitable compound for other purine transformations. The stability of the tert-butyl group at the N7 position is tested for classic model reactions, leading to the preparation of new 6,7-disubstituted purine derivatives, which is also interesting from the point of view of possible biological activity.
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Affiliation(s)
- Filip Nevrlka
- Department of Organic Chemistry, Faculty
of Science, Palacký University, 17. Listopadu 12, 771 46 Olomouc, Czech Republic
| | - Adam Bědroň
- Department of Organic Chemistry, Faculty
of Science, Palacký University, 17. Listopadu 12, 771 46 Olomouc, Czech Republic
| | - Michal Valenta
- Department of Organic Chemistry, Faculty
of Science, Palacký University, 17. Listopadu 12, 771 46 Olomouc, Czech Republic
| | - Lenka Tranová
- Department of Organic Chemistry, Faculty
of Science, Palacký University, 17. Listopadu 12, 771 46 Olomouc, Czech Republic
| | - Jakub Stýskala
- Department of Organic Chemistry, Faculty
of Science, Palacký University, 17. Listopadu 12, 771 46 Olomouc, Czech Republic
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Tranová L, Stýskala J. Study of the N7 Regioselective Glycosylation of 6-Chloropurine and 2,6-Dichloropurine with Tin and Titanium Tetrachloride. J Org Chem 2021; 86:13265-13275. [PMID: 34528791 DOI: 10.1021/acs.joc.1c01186] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
6-Chloropurine and 2,6-dichloropurine were regioselectively glycosylated at position 7 to give the corresponding peracetylated N7-nucleosides, which can be suitable for other purine transformations. In this work, we study the distribution of N7/N9-isomers produced via the Vorbrüggen method under different conditions, using an N-trimethylsilylated purine derivative and SnCl4 or TiCl4 as a catalyst. The main effort is devoted to reversing the disadvantageous predominant selectivity of most glycosylation reactions at the N9 position and thus to determining conditions that maximize the regioselectivity of glycosylation toward the desired N7-isomer.
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Affiliation(s)
- Lenka Tranová
- Department of Organic Chemistry, Faculty of Science, Palacký University, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
| | - Jakub Stýskala
- Department of Organic Chemistry, Faculty of Science, Palacký University, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
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Takahashi K, Suzuki M, Iwata Y, Shigeta S, Yamanishi K, De Clercq E. Selective Activity of Various Nucleoside and Nucleotide Analogues against Human Herpesvirus 6 and 7. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/095632029700800102] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We have developed a new sensitive enzyme immunoassay (EIA) and MTT (tetrazolium salt) assay for screening compounds against two variants of human herpesvirus 6 (HHV-6A, HHV-6B) and human herpesvirus 7 (HHV-7) and evaluated the anti-HHV-6 and HHV-7 activity of a series of anti-herpesvirus compounds and acyclic nucleoside phosphonate analogues. The results indicate that the pattern of activity of these compounds against these betaherpesviruses is similar to that for human cytomegalovirus (HCMV). The highest potency and selectivity against the two variants of HHV-6 and HHV-7 was demonstrated by S2242 (N7-isomer of 6-deoxy-ganciclovir). Also, ganciclovir (GCV), foscarnet, (phosphonoformic acid; PFA) and the acyclic nucleoside phosphonate analogues such as cidofovir (HPMPC) exhibited selective inhibitory activity against these viruses. Thymidine kinase (TK)-dependent drugs (acyclovir, ACV; brivudin, BVDU; and sorivudine, BVaraU) showed little, if any, activity. These results suggest a structural homology of the DNA polymerase and a lack of TK gene among these three betaherpesviruses (HHV-6, HHV-7 and HCMV). The finding that HHV-7 was highly sensitive to GCV also suggests that HHV-7 may have an HCMV-UL97-homologue gene for the phosphorylation of GCV. The present EIA method is more rapid and sensitive than the previously reported procedures and could be useful for the large-scale screening of compounds against HHV-6 and HHV-7.
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Affiliation(s)
- K Takahashi
- Department of Microbiology, Fukushima Medical College, 1 Hikarigaoka, Fukushima, 960-1 2, Japan
| | - M Suzuki
- Department of Microbiology, Fukushima Medical College, 1 Hikarigaoka, Fukushima, 960-1 2, Japan
| | - Y Iwata
- Department of Microbiology, Fukushima Medical College, 1 Hikarigaoka, Fukushima, 960-1 2, Japan
| | - S Shigeta
- Department of Microbiology, Fukushima Medical College, 1 Hikarigaoka, Fukushima, 960-1 2, Japan
| | - K Yamanishi
- Department of Microbiology, Osaka University School of Medicine, Osaka, Japan
| | - E De Clercq
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
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Coen N, Duraffour S, Snoeck R, Andrei G. KSHV targeted therapy: an update on inhibitors of viral lytic replication. Viruses 2014; 6:4731-59. [PMID: 25421895 PMCID: PMC4246246 DOI: 10.3390/v6114731] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 11/07/2014] [Accepted: 11/17/2014] [Indexed: 01/01/2023] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi’s sarcoma, primary effusion lymphoma and multicentric Castleman’s disease. Since the discovery of KSHV 20 years ago, there is still no standard treatment and the management of virus-associated malignancies remains toxic and incompletely efficacious. As the majority of tumor cells are latently infected with KSHV, currently marketed antivirals that target the virus lytic cycle have shown inconsistent results in clinic. Nevertheless, lytic replication plays a major role in disease progression and virus dissemination. Case reports and retrospective studies have pointed out the benefit of antiviral therapy in the treatment and prevention of KSHV-associated diseases. As a consequence, potent and selective antivirals are needed. This review focuses on the anti-KSHV activity, mode of action and current status of antiviral drugs targeting KSHV lytic cycle. Among these drugs, different subclasses of viral DNA polymerase inhibitors and compounds that do not target the viral DNA polymerase are being discussed. We also cover molecules that target cellular kinases, as well as the potential of new drug targets and animal models for antiviral testing.
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Affiliation(s)
- Natacha Coen
- Rega Institute for Medical Research, KU Leuven, B-3000 Leuven, Belgium.
| | - Sophie Duraffour
- Rega Institute for Medical Research, KU Leuven, B-3000 Leuven, Belgium.
| | - Robert Snoeck
- Rega Institute for Medical Research, KU Leuven, B-3000 Leuven, Belgium.
| | - Graciela Andrei
- Rega Institute for Medical Research, KU Leuven, B-3000 Leuven, Belgium.
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De Clercq E. Historical perspectives in the development of antiviral agents against poxviruses. Viruses 2010; 2:1322-1339. [PMID: 21994682 PMCID: PMC3185982 DOI: 10.3390/v2061322] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 05/28/2010] [Accepted: 05/28/2010] [Indexed: 12/02/2022] Open
Abstract
The poxvirus vaccinia virus (VV) served as the model virus for which the first antivirals, the thiosemicarbazones, were identified. This dates back to 1950; and, although there is at present no single antiviral drug specifically licensed for the chemotherapy or -prophylaxis of poxvirus infections, numerous candidate compounds have been described over the past 50 years. These compounds include interferon and inducers thereof (i.e., polyacrylic acid), 5-substituted 2’-deoxyuridines (i.e., idoxuridine), IMP dehydrogenase inhibitors, S-adenosylhomocysteine hydrolase inhibitors, acyclic nucleoside phosphonates (such as cidofovir) and alkoxyalkyl prodrugs thereof (such as CMX001), viral egress inhibitors (such as tecovirimat), and cellular kinase inhibitors (such as imatinib).
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, Department of Microbiology and Immunology, Minderbroedersstraat 10, B-3000 Leuven, Belgium
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Tian RR, Liao QJ, Chen X. Prevention and treatment of KSHV-associated diseases with antiviral drugs. Virol Sin 2008. [DOI: 10.1007/s12250-008-2995-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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6-Amino-2-thio- and 6-Aminouracils as Precursors for the Synthesis of Antiviral and Antimicrobial Methylenebis(2-thiouracils), Tricyclic Pyrimidines, and 6-Alkylthiopurine-2-ones. MONATSHEFTE FUR CHEMIE 2007. [DOI: 10.1007/s00706-007-0753-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
Smallpox (variola major), and the haemorrhagic fever viruses (filoviruses and arenaviruses) are classified as Category A biowarfare agents by the Centers for Disease Control. Category A agents pose a significant risk to public health and national security because they can be easily disseminated by aerosol, although with the exception of variola, they are not easily transmitted from person to person. An attack with these viruses would result in high morbidity and mortality and cause widespread panic. With the exception of smallpox and Argentine haemorrhagic fever virus, there are no vaccines or approved treatments to protect against these diseases. In this review we focus on promising prophylactic, therapeutic and disease modulating drugs (see Figure 1 for select chemical structures).
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Affiliation(s)
- Arthur J Goff
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, USA
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Smee DF, Wandersee MK, Bailey KW, Hostetler KY, Holy A, Sidwell RW. Characterization and treatment of cidofovir-resistant vaccinia (WR strain) virus infections in cell culture and in mice. Antivir Chem Chemother 2005; 16:203-11. [PMID: 16004083 DOI: 10.1177/095632020501600306] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The wild-type (WT) vaccinia (WR strain) virus is highly virulent to mice by intranasal inoculation, yet death can be prevented by cidofovir treatment. A cidofovir-resistant (CDV-R) mutant of the virus was developed by 15 Vero cell culture passages in order to determine cross-resistance to other inhibitors, growth characteristics, virulence in infected mice, and suitability of the animal model for studying antiviral therapies. Comparisons were made to the original WT virus and to a WT virus passaged 15 times in culture (WTp15 virus). Cidofovir inhibited WT, WTp15, and CDV-R viruses by 50% at 61, 56 and 790 microM, respectively, in plaque reduction assays, with similar inhibition seen in virus yield studies. Cross-resistance occurred with compounds related to cidofovir, but not with unrelated nucleosides. The resistant virus produced 300-fold fewer infectious particles (PFU) than WT and WTp15 viruses in mouse C1271 cells, yet replicated similarly in Vero (monkey) cells. The CDV-R virus was completely attenuated for virulence at 10(7) PFU per mouse in normal BALB/c mice and in severe combined immunodeficient (SCID) mice. The WTp15 virus was 100-fold less virulent than WT virus in BALB/c mice. Thus, the lack of virulence of the resistant virus in the animal model is explained partly by its reduced ability to replicate in mouse cells and by attenuation occurring as a result of extensive cell culturing (inferred from what occurred with the WTp15 virus). Lung and snout virus titre reduction parameters were used to assess antiviral activity of compounds in BALB/c mice infected intranasally with the CDV-R virus. Cidofovir, HDP-cidofovir and arabinofuranosyladenine treatments reduced lung virus titres <fourfold, and snout virus titres > or = eight-fold. The animal model appears to have limited utility in drug efficacy testing.
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Affiliation(s)
- Donald F Smee
- Institute for Antiviral Research, Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UT, USA.
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Lenaerts L, Verbeken E, De Clercq E, Naesens L. Mouse adenovirus type 1 infection in SCID mice: an experimental model for antiviral therapy of systemic adenovirus infections. Antimicrob Agents Chemother 2005; 49:4689-99. [PMID: 16251313 PMCID: PMC1280150 DOI: 10.1128/aac.49.11.4689-4699.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 07/15/2005] [Accepted: 08/16/2005] [Indexed: 11/20/2022] Open
Abstract
The importance of human adenovirus infections in immunocompromised patients urges for new and adequate antiadenovirus compounds. Since human adenoviruses are species specific, animal models for systemic adenovirus infections rely on a nonhuman adenovirus. We established mouse adenovirus type 1 (MAV-1) infection of BALB/c SCID mice as a model for the evaluation of antiadenovirus therapy. In vitro studies with mouse embryonic fibroblasts pointed to the acyclic nucleoside phosphonate cidofovir and the N-7-substituted acyclic derivative 2-amino-7-(1,3-dihydroxy-2-propoxymethyl)purine (S-2242) as markedly active compounds against MAV-1. SCID mice, infected intranasally with MAV-1, developed a fatal disseminated infection after approximately 19 days, characterized by hemorrhagic enteritis. Several techniques were optimized to monitor viral, immunological, and pathological aspects of MAV-1 infection. Real-time PCR quantification of viral DNA revealed that after replication in the lungs, virus disseminated to several organs, including the brain, liver, spleen, intestine, heart, and kidneys (resulting in viruria). Immunohistochemical staining showed that MAV-1 was localized in the endothelial cells of the affected organs. Using reverse transcription-PCR, tissue levels of proinflammatory cytokines (i.e., interleukin-1beta and tumor necrosis factor alpha) were found to be markedly increased. The MAV-1/SCID model appears to be an appropriate model for in vivo evaluation of antiadenovirus agents. Treatment with cidofovir or S-2242 at a dose of 100 mg per kg of body weight resulted in a significant delay in MAV-1-related death, although these antivirals were unable to completely suppress virus replication despite continued drug treatment. These findings suggest that complete virus clearance during antiviral therapy for disseminated adenovirus infection may require an efficient adaptive immune response from the host.
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Affiliation(s)
- L Lenaerts
- Rega Institute for Medical Research, Division of Virology and Chemotherapy, Katholieke Universiteit Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium
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Michel D, Mertens T. The UL97 protein kinase of human cytomegalovirus and homologues in other herpesviruses: impact on virus and host. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1697:169-80. [PMID: 15023359 DOI: 10.1016/j.bbapap.2003.11.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2003] [Accepted: 11/12/2003] [Indexed: 11/16/2022]
Abstract
The human herpesviruses, herpes simplex virus 1 (HSV-1), HSV-2, varicella zoster virus (VZV), Epstein-Barr virus (EBV), human cytomegalovirus (HCMV), human herpesvirus 6A (HHV-6A), HHV-6B, HHV-7 and HHV-8, establish persistent infections with possible recurrence during immunosuppression. HCMV replication is inhibited by the nucleoside analogue ganciclovir (GCV), the compound of choice for the treatment of HCMV diseases and preemptive treatment of infections. The viral UL97 protein (pUL97) which shares homologies with protein kinases and bacterial phosphotransferases is able to monophosphorylate GCV. Homologues of pUL97 are found in HSV (UL13), VZV (ORF47), EBV (BGLF4), HHV-6 (U69), HHV-8 (ORF36) as well as in murine CMV (M97) or rat CMV (R97). Several indolocarbazoles have been reported to be specific inhibitors of pUL97. The protein is important for efficient replication of the virus. Autophosphorylation of pUL97 was observed using different experimental systems. Most recently, it has been shown that pUL97 interacts with the DNA polymerase processivity factor pUL44. Indolocarbazole protein kinase inhibitors are promising lead compounds for the development of more specific inhibitors of HCMV.
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Affiliation(s)
- Detlef Michel
- Universitätsklinikum Ulm, Abteilung Virologie, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
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Wang R, Chen X, Drach JC, Kern ER, Zemlicka J. Synthesis and biological activity of 2-aminopurine methylenecyclopropane analogues of nucleosides. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2003; 22:135-44. [PMID: 12744601 DOI: 10.1081/ncn-120019502] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Synthesis and biological activity of racemic 2-aminopurine methylenecyclopropane analogues of nucleosides 4, 5, 10 and 11 is described. One-pot alkylation-elimination of 2-aminopurine (6) with dibromide 7 gave a mixture of four isomeric methylenecyclopropanes. The (E, Z)-N9 and (E, Z)-N7 isomers 8 and 9 were resolved by chromatography on silica gel. Deacetylation of 8 afforded the respective (Z)-N9 and (E)-N9 isomers 4 and 10 which were separated by chromatography on silica gel. In a similar fashion, (E, Z)-N7 mixture 9 furnished (Z)-N7 and (E)-N7 isomers 5 and 11. The S-(+)-enantiomer 4 was obtained by desulfurization of (S)-(+)-6-thiosynguanol (13) with Raney Ni. Compound 13 was obtained from (S)-(+)-2-amino-6-chloro derivative 12 and NaSH in methanol. Racemic analogues 4, 5, 10 and 11 were inactive against HCMV, HSV-1, HSV-2, EBV and VZV. Enantiomer (S)-(+)-4 inhibited replication of HSV-1 in BSC-1 cells (ELISA) with EC50 35 microM and it was non-cytotoxic in KB cells (CC50 > 100 microM). Compound (S)-(+)-4 was also moderately effective against VZV in HFF culture with EC50/CC50 (microM) 60/>460 and it was a substrate for xanthine oxidase.
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Affiliation(s)
- Ruifang Wang
- Developmental Chemotherapy Program, Department of Chemistry, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan 48201-1379, USA
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13
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Smee DF, Bailey KW, Sidwell RW. Treatment of lethal cowpox virus respiratory infections in mice with 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine and its orally active diacetate ester prodrug. Antiviral Res 2002; 54:113-20. [PMID: 12062396 DOI: 10.1016/s0166-3542(01)00217-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The acyclic purine nucleoside analog, 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine (S2242) and its orally active diacetate ester prodrug (HOE961) were reported to be potent inhibitors of vaccinia virus replication in cell culture and in infected mice. These compounds were evaluated further, using infections with the related cowpox virus. Against a wild-type (WT) cowpox virus strain in mouse C127I cell culture, 50% effective concentrations (EC(50), determined by plaque reduction assays) of S2242 and cidofovir (a positive control) were 3.5 and 1.0 microM, respectively. EC(50) values obtained against a cidofovir-resistant strain of the virus were 33 and 230 microM, respectively. Compounds were at least ten-fold less potent against WT virus in Vero cells than C127I cells. S2242 and cidofovir were 50% inhibitory to the proliferation of uninfected C127I cells at 340 and 180 microM, respectively, but neither compound inhibited Vero cell growth at 1000 microM. Mice were lethally infected with cowpox virus by intranasal inoculation, followed 24 h later by antiviral treatment for 5 consecutive days. Once or twice daily intraperitoneal (i.p.) treatments with either S2242 or HOE961 at 100 mg/kg per day resulted in > or = 70 survival compared with no survivors in the placebo group. Lower doses of these compounds (10 and 30 mg/kg per day) were not protective, however. Cidofovir was 100% protective at 30 mg/kg per day. A 10-day course of treatment gave comparable survival results and demonstrated the oral efficacy of HOE961. Treatments with S2242 (100 mg/kg per day) and cidofovir (30 mg/kg per day) each reduced lung and nasal virus titers by approximately ten-fold, whereas, HOE961 (100 mg/kg per day) was less active. Overall, S2242 and HOE961 were found to be effective against cowpox virus infections in mice but were less potent than cidofovir. Since, HOE961 was orally active, it may have advantages over the other parenterally administered compounds for treating orthopoxvirus infections.
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Affiliation(s)
- Donald F Smee
- Department of Animal, Dairy and Veterinary Sciences, Institute for Antiviral Research, Utah State University, 84322-5600, Logan, UT 84322-5600, USA.
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De Clercq E, Naesens L, De Bolle L, Schols D, Zhang Y, Neyts J. Antiviral agents active against human herpesviruses HHV-6, HHV-7 and HHV-8. Rev Med Virol 2001; 11:381-95. [PMID: 11747000 DOI: 10.1002/rmv.336] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A series of antiviral compounds were examined for their activity against human herpesvirus type 6 (HHV-6), type 7 (HHV-7) and type 8 (HHV-8). They were selected either because they are already approved for clinical use in the treatment of herpesvirus infections (acyclovir, valaciclovir, penciclovir, famciclovir, ganciclovir, brivudin, foscarnet and cidofovir) or have demonstrated marked activity against herpesviruses (lobucavir, H2G, A-5021, D/L-cyclohexenyl G and S2242). In view of their host cell specificity, different cells and assays had to be used for determining antiviral activity against these three viruses. The most potent compounds with the highest antiviral selectivity index were: (i) for HHV-6; foscarnet, S2242, A-5021 and cidofovir; (ii) for HHV-7; S2242, cidofovir and foscarnet; and (iii) for HHV-8; S2242, cidofovir and ganciclovir. As mycophenolic acid has been shown to enhance significantly the activity of acyclic guanosine analogues (such as acyclovir, penciclovir and ganciclovir) in vitro against HSV-1, HSV-2, VZV and HCMV, it would seem worth evaluating whether mycophenolic acid also potentiates the activity of these acyclic guanosine analogues against HHV-6, -7 and -8.
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Affiliation(s)
- E De Clercq
- Division of Virology and Chemotherapy, Department of Microbiology and Immunology, K.U. Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium
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15
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De Clercq E. Vaccinia virus inhibitors as a paradigm for the chemotherapy of poxvirus infections. Clin Microbiol Rev 2001; 14:382-97. [PMID: 11292644 PMCID: PMC88980 DOI: 10.1128/cmr.14.2.382-397.2001] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Poxviruses continue to pose a major threat to human health. Monkeypox is endemic in central Africa, and the discontinuation of the vaccination (with vaccinia virus) has rendered most humans vulnerable to variola virus, the etiologic agent of smallpox, should this virus be used in biological warfare or terrorism. However, a large variety of compounds have been described that are potent inhibitors of vaccinia virus replication and could be expected to be active against other poxviruses as well. These compounds could be grouped in different classes: (i) IMP dehydrogenase inhibitors (e.g., EICAR); (ii) SAH hydrolase inhibitors (e.g., 5'-noraristeromycin, 3-deazaneplanocin A, and various neplanocin A derivatives); (iii) OMP decarboxylase inhibitors (e.g., pyrazofurin) and CTP synthetase inhibitors (e.g., cyclopentenyl cytosine); (iv) thymidylate synthase inhibitors (e.g., 5-substituted 2'-deoxyuridines); (v) nucleoside analogues that are targeted at viral DNA synthesis (e.g., Ara-A); (vi) acyclic nucleoside phosphonates [e.g., (S)-HPMPA and (S)-HPMPC (cidofovir)]; and (vii) polyanionic substances (e.g., polyacrylic acid). All these compounds could be considered potential candidate drugs for the therapy and prophylaxis of poxvirus infections at large. Some of these compounds, in particular polyacrylic acid and cidofovir, were found to generate, on single-dose administration, a long-lasting protective efficacy against vaccinia virus infection in vivo. Cidofovir, which has been approved for the treatment of cytomegalovirus retinitis in immunocompromised patients, was also found to protect mice, again when given as a single dose, against a lethal aerosolized or intranasal cowpox virus challenge. In a biological warfare scenario, it would be advantageous to be able to use a single treatment for an individual exposed to an aerosolized poxvirus. Cidofovir thus holds great promise for treating human smallpox, monkeypox, and other poxvirus infections. Anecdotal experience points to the efficacy of cidofovir in the treatment of the poxvirus infections molluscum contagiosum and orf (ecthyma contagiosum) in immunosuppressed patients.
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Affiliation(s)
- E De Clercq
- Division of Virology and Chemotherapy, Department of Microbiology and Immunology, Rega Institute for Medical Research, K.U. Leuven, B-3000 Leuven, Belgium.
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16
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De Clercq E, Andrei G, Snoeck R, De Bolle L, Naesens L, Degrève B, Balzarini J, Zhang Y, Schols D, Leyssen P, Ying C, Neyts J. Acyclic/carbocyclic guanosine analogues as anti-herpesvirus agents. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2001; 20:271-85. [PMID: 11563039 DOI: 10.1081/ncn-100002298] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Several guanosine analogues, i.e. acyclovir (and its oral prodrug valaciclovir), penciclovir (in its oral prodrug form, famciclovir) and ganciclovir, are widely used for the treatment of herpesvirus [i.e. herpes simplex virus type 1 (HSV-1), and type 2 (HSV-2), varicella-zoster virus (VZV) and/or human cytomegalovirus (HCMV)] infections. In recent years, several new guanosine analogues have been developed, including the 3-membered cyclopropylmethyl and -methenyl derivatives (A-5021 and synguanol) and the 6-membered D- and L-cyclohexenyl derivatives. The activity of the acyclic/carbocyclic guanosine analogues has been determined against a wide spectrum of viruses, including the HSV-1, HSV-2, VZV, HCMV, and also human herpesviruses type 6 (HHV-6), type 7 (HHV-7) and type 8 (HHV-8), and hepatitis B virus (HBV). The new guanosine analogues (i.e. A-5021 and D- and L-cyclohexenyl G) were found to be particularly active against those viruses (HSV-1, HSV-2, VZV) that encode for a specific thymidine kinase (TK), suggesting that their antiviral activity (at least partially) depends on phosphorylation by the virus-induced TK. Marked antiviral activity was also noted with A-5021 against HHV-6 and with D- and L-cyclohexenyl G against HCMV and HBV. The antiviral activity of the acyclic/carbocyclic nucleoside analogues could be markedly potentiated by mycophenolic acid, a potent inhibitor of inosine 5'-monophosphate (IMP) dehydrogenase. The new carbocyclic guanosine analogues (i.e. A-5021 and D- and L-cyclohexenyl G) hold great promise, not only as antiviral agents for the treatment of herpesvirus infections, but also an antitumor agents for the combined gene therapy/chemotherapy of cancer, provided that (part of) the tumor cells have been transduced by the viral (HSV-1, VZV) TK gene.
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Affiliation(s)
- E De Clercq
- Rega Institute for Medical Research, K. U. Leuven, B-3000 Leuven, Belgium
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Neyts J, De Clercq E. Efficacy of 2-amino-7-(1,3-dihydroxy-2-propoxymethyl)purine for treatment of vaccinia virus (orthopoxvirus) infections in mice. Antimicrob Agents Chemother 2001; 45:84-7. [PMID: 11120949 PMCID: PMC90244 DOI: 10.1128/aac.45.1.84-87.2001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have previously shown that the N-7 substituted acyclic nucleoside analog 2-amino-7-[1,3-dihydroxy-2-propoxy)methyl]purine (compound S2242) is, both in vitro and in animal models, a potent inhibitor of the replication of several herpesviruses (Neyts et al., Antimicrob. Agents Chemother. 39:56-60, 1995). Here we report on the potent and selective antiviral activity of S2242 against vaccinia virus (VV), an orthopoxvirus. The 50% effective concentrations for inhibition of VV-induced cytopathic effect and viral DNA synthesis in cell culture were 2.4 and 0.2 microg/ml, respectively. We next studied the efficacy of S2242 in VV-infected mice. Immunocompetent NMRI mice that had been inoculated intravenously with VV developed tail lesions. Mice that had been treated for 5 consecutive days via the subcutaneous (s.c.) route with 100 mg of the diacetate ester prodrug of S2242 (compound H961) per kg of body weight did not develop any lesions and demonstrated no adverse effects. Severe combined immunodeficient (SCID) mice that had been inoculated intraperitoneally with VV became sick and died within 1 month after infection. Following treatment with H961 at 100 mg/kg for 10 consecutive days (either via oral gavage or s.c. injection) VV-inoculated SCID mice were completely protected, for at least 3 months, against virus-induced morbidity and mortality. At that time, no virus could be recovered from the organs of these mice (as assessed by titration for infectious virus, a DNA hybridization assay, and a PCR for VV-specific sequences). Compound S2242 and its oral prodrug H961 could be useful in treatment of orthopoxvirus infections.
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Affiliation(s)
- J Neyts
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, 3000 Leuven, Belgium.
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18
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De Clercq E. Guanosine analogues as anti-herpesvirus agents. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2000; 19:1531-41. [PMID: 11200257 DOI: 10.1080/15257770008045444] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Several guanosine analogues, i.e. acyclovir (and its oral prodrug valaciclovir), penciclovir (in its oral prodrug form, famciclovir) and ganciclovir, are widely used for the treatment of herpesvirus (i.e. HSV-1, HSV-2, VZV and HCMV) infections. In recent years, several new guanosine analogues have been developed, including the 3-membered (cyclopropyl) sugar derivative A-5021 and the 6-membered D- and L-cyclohexenyl derivatives. Prominent features shared by all guanosine analogues are the following. They depend for their phosphorylation on the virus-encoded thymidine kinase (TK), which makes them particularly effective against those viruses (HSV-1, HSV-2 and VZV) that encoded for such TK. They are also active against HCMV, whether or not they are subject of phosphorylation by the HCMV-induced UL97 protein kinase. Their antiviral activity can be markedly potentiated by mycophenolic acid, an IMP dehydrogenase inhibitor, and they hold great promise, not only as antiviral agents for the treatment of herpesvirus infections, but also as antitumor agents for the combined gene therapy/chemotherapy of cancer, provided that (part of) the tumor cells have been transfected by the viral TK gene.
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Affiliation(s)
- E De Clercq
- Rega Institute for Medical Research K.U. Leuven, Belgium
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Suzutani T, Ogasawara M, Shibaki T, Azuma M. Susceptibility of protein kinase (ORF47)-deficient varicella-zoster virus strains to anti-herpesvirus nucleosides. Antiviral Res 2000; 45:79-82. [PMID: 10774592 DOI: 10.1016/s0166-3542(99)00079-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To clarify whether varicella-zoster virus (VZV) protein kinase (PK; ORF47) takes part in phosphorylation of anti-herpesvirus nucleosides, thymidine kinase (TK) deficient, and PK/TK double deficient recombinant VZV strains were isolated and their susceptibility, and that of wild type and PK-deficient strains to various nucleoside analogs was evaluated. The PK-deficient VZV strains showed a sensitivity equal to that of the wild type strain against all compounds tested, including ganciclovir. This indicates that PK is not involved in phosphorylation of the tested nucleosides in VZV-infected cells.
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Affiliation(s)
- T Suzutani
- Department of Microbiology, Asahikawa Medical College, Japan.
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Zhang Y, Schols D, De Clercq E. Selective activity of various antiviral compounds against HHV-7 infection. Antiviral Res 1999; 43:23-35. [PMID: 10480261 DOI: 10.1016/s0166-3542(99)00031-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Human herpesvirus virus type 7 (HHV-7) is a T-lymphotropic herpesvirus which uses the CD4 receptor as main receptor to infect its target cells. Measuring the decrease of CD4 expression during HHV-7 infection is a convenient and accurate method to monitor the efficacy of antiviral agents against HHV-7 infection. Different classes of compounds, such as heparin, pentosan polysulfate (PS), dextran sulfate (DS), aurintricarboxylic acid (ATA), phosphonoformic acid (PFA), 9-(2-phosphonylmethoxyethyl)adenine (PMEA), 2-amino-7-[(1,3-dihydroxy-2-propoxy) methyl] purine (S2242), polyvinylalcohol sulfate (PVAS) and the co-polymer of vinylalcohol sulfate with acrylic acid (PAVAS), acyclovir (ACV), ganciclovir (GCV), penciclovir (PCV), brivudin (BVDU), cidofovir (HPMPC), lobucavir, (R)-9-[4-hydroxy-2-(hydroxymethyl)butyl]guanine] (H2G), (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA) and sorivudine (BVaraU), were evaluated for their anti-HHV-7 activity in the SupT1 T cell line and in purified CD4+ T lymphocytes. Antiviral activity was monitored by inhibition of: (i) CD4 expression down-regulation; (ii) giant cell formation and (iii) apoptosis induction. In general, PS, DS, PVAS, PAVAS, ATA, PFA, PMEA, S2242, lobucavir and HPMPC had comparable anti-HHV-7 activity in the two cell lines, irrespective of the parameters followed to monitor antiviral activity. One of the exceptions was heparin which had an IC50 of 9.6 microg/ml in SupT1 cells and >250 microg/ml in CD4+ T lymphocytes. The compounds PCV, GCV, H2G and PMPA showed some activity in CD4+ T lymphocytes, but not in SupT1 cells. ACV, BVDU and BVaraU did not show activity in either cell system. None of the chemokines tested, such as platelet factor-4 (PF-4), eotaxin, stromal cell-derived factor 1alpha(SDF-1alpha) and RANTES, had detectable activity against HHV-7. In contrast, the HIV-1 envelope glycoprotein, gp120, and the two anti-CD4 mAbs, 13B8-2 and OKT4, were clearly active against HHV-7 infection.
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Affiliation(s)
- Y Zhang
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, Belgium.
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Cannon JS, Hamzeh F, Moore S, Nicholas J, Ambinder RF. Human herpesvirus 8-encoded thymidine kinase and phosphotransferase homologues confer sensitivity to ganciclovir. J Virol 1999; 73:4786-93. [PMID: 10233939 PMCID: PMC112521 DOI: 10.1128/jvi.73.6.4786-4793.1999] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human herpesvirus 8 (HHV-8) sensitivity to the nucleoside analog ganciclovir (GCV) suggests the presence of a virally encoded kinase that catalyzes the initial phosphorylation of GCV. Analysis of the HHV-8 genome identified two candidate kinases: proteins encoded by open reading frame (ORF) 21, with homology to the herpesvirus thymidine kinases (TK), and ORF 36, with homology to the herpesvirus phosphotransferases (PT). Experiments presented here show that both ORF 21 and ORF 36 encode GCV kinase activities as demonstrated by GCV phosphorylation and GCV-mediated cell death. In both regards the PT homologue ORF 36 was more active than the TK homologue ORF 21. ORF 21, but not ORF 36, weakly sensitized cells to killing by penciclovir. Neither ORF sensitized cells to killing by (E)-5-(2-bromovinyl)-2'-deoxyuridine.
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Affiliation(s)
- J S Cannon
- Departments of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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22
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Meerbach A, Holý A, Wutzler P, De Clercq E, Neyts J. Inhibitory effects of novel nucleoside and nucleotide analogues on Epstein-Barr virus replication. Antivir Chem Chemother 1998; 9:275-82. [PMID: 9875407 DOI: 10.1177/095632029800900309] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The anti-Epstein-Barr virus (EBV) activity of different classes of compounds was assessed by means of an EBV DNA hybridization assay using a digoxigenin-labelled probe specific for the BamHI W fragment of the EBV genome, as well as by measuring viral capsid antigen (VCA) expression after a 7 day incubation period of P3HR-1 producer cells with the test substances. Acyclovir, ganciclovir, cidofovir and zidovudine were included as reference compounds. Several compounds proved to be potent and selective inhibitors of EBV DNA synthesis and VCA expression. Of the new compounds that were evaluated for their anti-EBV activity, the highest efficacy (lowest EC50) and highest selectivity index (SI) were shown by the purine nucleoside analogue 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine (S2242) (EC50 0.6 ng/ml; SI 600), the acyclic nucleoside phosphonate analogues 9-(2-phosphono -methoxyethyl)-6-dimethylaminopurine (EC50 1.1 micrograms/ml; SI 91), 9-(2-phosphonomethoxyethyl)-2- amino-6-benzhydrylaminopurine (EC50 1.3 micrograms/ml; SI 29), 7-(2-phosphonomethoxyethyl)-6-dimethyl-aminopurine (EC50 0.8 microgram/ml; SI 56), 9-(R)-(2-phosphonomethoxypropyl)-6-(2-dimethylaminoethyl)-aminopur ine (EC50 0.5 microgram/ml; SI 42), the 2',3'-dideoxythymidine derivative 3'-oximino-2',3'-dideoxythymidine (EC50 1.5 micrograms/ml; SI 65), and 1-(2,3- dideoxy-3-N-hydroxyamino-beta-D-threo-pentafuranyl)pentafuranos yl)thymine (EC50 4.1 micrograms/ml; SI > 24).
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Affiliation(s)
- A Meerbach
- Institute for Antiviral Chemotherapy, Friedrich-Schiller-University Jena, Erfurt, Germany
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Neyts J, Balzarini J, Andrei G, Chaoyong Z, Snoeck R, Zimmermann A, Mertens T, Karlsson A, De Clercq E. Intracellular metabolism of the N7-substituted acyclic nucleoside analog 2-amino-7-(1,3-dihydroxy-2-propoxymethyl)purine, a potent inhibitor of herpesvirus replication. Mol Pharmacol 1998; 53:157-65. [PMID: 9443944 DOI: 10.1124/mol.53.1.157] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We investigated the intracellular metabolism of S2242 (2-amino-7-(1,3-dihydroxy-2-propoxymethyl)purine), the only known antivirally active acyclic nucleoside analogue with the side chain substituted at the N7 position of the purine ring. Uptake of S2242 by CEM cells increased linearly with increasing extracellular concentrations of the compound and was blocked by inhibitors of nucleoside transport. S2242 was phosphorylated in a time- and concentration-dependent manner to its monophosphates, diphosphates, and triphosphates. Intracellular half-life of the diphosphates and triphosphates in CEM cells was approximately 3-6 hr. A strong correlation was found between the cytostatic action of the compound and its phosphorylation in different cell lines. In accord with the findings that (1) the cytostatic potential of S2242 is reversed by deoxycytidine (dCyd) and (2) the growth of deoxycytidine kinase-deficient (dCK-) cells is refractory to the inhibitory effect of S2242, the amount of metabolites formed from S2242 in the dCK- cell line was approximately one hundredth of that in the wild-type cells. The observation that purified dCK phosphorylates S2242 to its monophosphate further corroborates these results. The activity of S2242 against herpes simplex virus, varicella-zoster virus, and human herpesvirus type 6 was reversed by 50-100-fold on the addition of exogenous dCyd. Compound S2242 was not preferentially phosphorylated in herpes simplex virus 1-, varicella-zoster virus-, or human herpesvirus type 6-infected cells (Vero, human embryonic lung, and HSB-2 cells, respectively), and exogenously added dCyd reduced substantially the formation of S2242 metabolites in these cells. In human cytomegalovirus (HCMV)-infected human embryonic lung cells, a 5-25-fold increase in S2242 metabolite formation was observed compared with the noninfected cells, suggesting that an HCMV-encoded or -induced enzyme causes the specific phosphorylation of S2242. Exogenously added dCyd had little effect on the activity of S2242 against HCMV and on the phosphorylation of the compound in HCMV-infected cells. S2242 was not specifically phosphorylated by the HCMV-encoded UL-97 kinase in cells infected with a vaccinia/UL-97 recombinant. S2242 was found to be a substrate (K(m) = 90 microM) for purified human deoxyguanosine kinase; the latter enzyme was stimulated 3-4-fold in HCMV-infected cells.
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Affiliation(s)
- J Neyts
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, Belgium.
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24
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Revankar GR, Ojwang JO, Mustain SD, Rando RF, De Clercq E, Huffman JH, Drach JC, Sommadossi JP, Lewis AF. Thiazolo[4,5-d]pyrimidines. Part II. Synthesis and anti-human cytomegalovirus activity in vitro of certain acyclonucleosides and acyclonucleotides derived from the guanine analogue 5-aminothiazolo[4,5-d]pyrimidine-2,7(3H,6H)-dione. Antivir Chem Chemother 1998; 9:53-63. [PMID: 9875377 DOI: 10.1177/095632029800900102] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The synthesis and in vitro antiviral activity of certain hydroxyalkoxymethyl, hydroxyalkyl, hydroxyalkenyl and phosphonoalkenyl derivatives of the guanine congener 5-aminothiazolo[4,5-d]pyrimidine-2,7(3H,6H)-dione are reported. The compounds of this study were selected for their structural similarity to acyclonucleosides with known anti-herpesvirus activity. 5-Amino-3-[(Z)-4-hydroxy-2-buten-1-yl]thiazolo[4,5-d]pyrimidine-2, 7(3H,6H)- dione was the only member of the series to display significant in vitro activity against human cytomegalovirus (HCMV); however, this compound did not inhibit other herpesviruses, human immunodeficiency virus type 1 or murine cytomegalovirus. It was found to have a cytotoxicity profile similar to that of ganciclovir (DHPG). The antiviral effect was found to be sensitive to the initial viral input and the time of addition during the virus replication cycle. Significantly, the compound was found to have equal anti-HCMV activity, against standard virus strains, to DHPG, but also showed potent activity against DHPG-resistant virus strains, except for a strain mutated in the UL97 (phosphotransferase) gene.
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Affiliation(s)
- G R Revankar
- Aronex Pharmaceuticals, Woodlands, TX 77381-4223, USA
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25
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Neyts J, De Clercq E. In vitro and in vivo inhibition of murine gamma herpesvirus 68 replication by selected antiviral agents. Antimicrob Agents Chemother 1998; 42:170-2. [PMID: 9449280 PMCID: PMC105475 DOI: 10.1128/aac.42.1.170] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We have evaluated the susceptibility of the murine gamma herpesvirus 68 (MHV-68) to a variety of antiviral agents. The acyclic nucleoside phosphonate analogs cidofovir [(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl) cytosine], (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA), and adefovir [9-(2-phosphonylmethoxyethyl)adenine] efficiently inhibited the replication of the virus in Vero cells (50% effective concentrations [EC50s], 0.008, 0.06, and 2.2 microg/ml, respectively). Acyclovir, ganciclovir, and brivudin [(E)-5-(2-bromovinyl)-2'-deoxyuridine] had equipotent activities (EC50s, 1.5 to 8 microg/ml), whereas foscarnet and penciclovir were less effective (EC50s, 23 and > or =30 microg/ml, respectively). The novel N-7-substituted nucleoside analog S2242 [7-(1,3-dihydroxy-2-propoxymethyl)purine] inhibited MHV-68 replication by 50% at 0.2 microg/ml. The susceptibilities of MHV-68 and Epstein-Barr virus (EBV) to cidofovir, HPMPA, adefovir, and acyclovir were found to be comparable. However, for penciclovir, ganciclovir, brivudin, and S2242, major differences in the sensitivity of MHV-68 and EBV were observed, suggesting that MHV-68 is not always an optimal surrogate for the study of antiviral strategies for EBV. When evaluated with a model for lethal MHV-68 infections in mice with severe combined immunodeficiency, cidofovir proved to be very efficient in protecting against virus-induced mortality (100% survival at 50 days postinfection), whereas acyclovir, brivudin, and adefovir had little or no effect.
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Affiliation(s)
- J Neyts
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, Belgium.
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26
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Abstract
We studied the susceptibility of human herpesvirus 8 (HHV-8) to a number of antiherpesvirus agents. The acyclic nucleoside phosphonate (ANP) analogs cidofovir and HPMPA [(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)adenine] effected potent inhibition of HHV-8 DNA synthesis, with 50% effective concentrations (EC50) of 6.3 and 0.6 microM, respectively. Adefovir, an ANP with both antiretrovirus and antiherpesvirus activity, blocked HHV-8 DNA replication at a fourfold-lower concentration than did foscarnet (EC50 of 39 and 177 microM, respectively). The most potent inhibitory effect was obtained with the N-7-substituted nucleoside analog S2242 (EC50, 0.11 microM). The nucleoside analogs acyclovir, penciclovir, H2G ((R)-9-[4-hydroxy-2-(hydroxymethyl) butyl]guanine), and brivudine had weak to moderate effects (EC50 of > or =75, 43, 42, and 24 microM, respectively, and EC90 of > or =75 microM), whereas ganciclovir elicited pronounced anti-HHV-8 activity (EC50, 8.9 microM).
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Affiliation(s)
- J Neyts
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, Belgium.
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El Ashry E, El Kilany Y. Acyclonucleosides: Part 3. tri-, tetra-, and pentaseco-Nucleosides**Part 1 can be found in Volume 67; Part 2 appears in Volume 68. ADVANCES IN HETEROCYCLIC CHEMISTRY 1997. [DOI: 10.1016/s0065-2725(08)60082-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Kodama E, Shigeta S, Suzuki T, De Clercq E. Application of a gastric cancer cell line (MKN-28) for anti-adenovirus screening using the MTT method. Antiviral Res 1996; 31:159-64. [PMID: 8811200 DOI: 10.1016/0166-3542(96)06966-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We established a sensitive and accurate method for screening of anti-adenovirus agents using the 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. MKN-28 cells, which are well-differentiated stomach adenocarcinoma cells, were used for adenovirus (ADV) infection and examined for the anti-ADV activities of several established anti-herpes virus agents. ADV-11 is the causative agent of respiratory and urinary infections. It frequently causes hemorrhagic cystitis in immunocompromised hosts. One laboratory strain and 4 clinical isolates of ADV-11 were examined, and found susceptible (in order of decreasing activity) to 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine (S-2242), (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine[(S)-HPMPA ], and (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine[(S)-HPMPC++ +]. On the other hand, ganciclovir and iododeoxyuridine were only weakly effective and dextran sulfate was ineffective. Our findings indicate that the MTT assay using MKN-28 cells is applicable to anti-ADV screening. The anti-ADV activity of (S)-HPMPA and (S)-HPMPC was confirmed, and, furthermore, S-2242 emerged as a highly potent and selective inhibitor of ADV-11.
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Affiliation(s)
- E Kodama
- Department of Microbiology, Fukushima Medical College, Japan
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29
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Reymen D, Naesens L, Balzarini J, Holý A, Dvoráková H, De Clercq E. Antiviral activity of selected acyclic nucleoside analogues against human herpesvirus 6. Antiviral Res 1995; 28:343-57. [PMID: 8669893 DOI: 10.1016/0166-3542(95)00058-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Human herpesvirus 6 (HHV-6) was examined in vitro for its sensitivity to a broad range of nucleoside analogues, including acyclovir (ACV), ganciclovir (GCV), penciclovir (PCV), buciclovir (BCV), brivudin (BVDU), the N7-isomer of 6-deoxyganciclovir (S2242), foscarnet (phosphonoformic acid, PFA), and several acyclic nucleoside phosphonate (ANP) analogues such as (S)-HPMPA, (S)-HPMPC, PMEA and PMEDAP. Antiviral efficacy was monitored microscopically by the inhibitory effect of the compounds on HHV-6-induced cytopathic effect in human T-lymphoblastoid HSB-2 cells. In addition, a newly developed immunofluorescence/flow cytometric assay (FACS) was used to determine HHV-6-specific antigen expression. A close correlation was observed between the antiviral data obtained by the microscopic assay and the flow cytometric assay. Marked antiviral efficacy was noted for S2242, PFA and the ANP analogues (S)-HPMPA, (S)-HPMPC, (S)-cHPMPC, (S)-3-deaza-HPMPA, (S)-3-deaza-cHPMPA, (S)-HPMPG and (R)-HPMPG. Also, PMEA and PMEDAP proved highly active against HHV-6 infection, whereas (S)-FPMPA and (R)-PMPDAP were inactive. ACV was only slightly protective against HHV-6, and no activity was found for GCV, PCV, BCV and BVDU. Overall, the efficacy of the nucleoside analogues against HHV-6 appeared to correlate with their efficacy against human cytomegalovirus (HCMV).
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Affiliation(s)
- D Reymen
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, Belgium
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30
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Bryant M, Getman D, Smidt M, Marr J, Clare M, Dillard R, Lansky D, DeCrescenzo G, Heintz R, Houseman K. SC-52151, a novel inhibitor of the human immunodeficiency virus protease. Antimicrob Agents Chemother 1995; 39:2229-34. [PMID: 8619573 PMCID: PMC162920 DOI: 10.1128/aac.39.10.2229] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
SC-52151 is a potent, selective, tight-binding human immunodeficiency virus (HIV) protease inhibitor containing the novel (R)-(hydroxyethyl) urea isostere. The mean 50% effective concentration for lymphotropic, monocytotropic strains and field isolates of HIV type 1 (HIV-1), HIV-2, and simian immunodeficiency virus is 26 ng/ml (43 nM). The combination of SC-52151 and nucleoside reverse transcriptase inhibitors synergistically inhibited HIV-1 replication without additive toxicity. An extended postantiviral effect correlates with inhibition of gag and gag-pol polyprotein processing. SC-52151 is highly protein bound ( >90%) in human plasma, and the level of partitioning into erythrocytes is low. Physiological concentrations of alpha-1-acid glycoprotein, but not albumin, substantially affect the antiviral potency of SC-52151. The oral bioavailability of [14C]SC-52151 is 17% when it is administered as an elixir to the rat, dog, or monkey. Oxidation of the t-butyl moiety is the major route of biotransformation, and elimination is mainly by biliary excretion. No toxicologically significant effects have been observed in animals. Pharmacokinetic and metabolism studies in multiple animal species predict 20 to 30% systemic bioavailability, an elimination half-life of 1 to 2 h, and a volume of distribution of greater than 3 liters/kg in humans.
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Affiliation(s)
- M Bryant
- G. D. Searle/Monsanto, St. Louis, Missouri 63198, USA
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31
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De Clercq E. Trends in the development of new antiviral agents for the chemotherapy of infections caused by herpesviruses and retroviruses. Rev Med Virol 1995. [DOI: 10.1002/rmv.1980050305] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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32
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Besen G, Chavez-de la Paz E, Tatebayashi M, Flores-Aguilar M, Gangan PA, Munguia D, Wiley CA, Jähne G, Winkler I, Helsberg M. Evaluation of retinal toxicity and efficacy of the anticytomegalovirus compound 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine. Antimicrob Agents Chemother 1995; 39:1485-8. [PMID: 7492090 PMCID: PMC162767 DOI: 10.1128/aac.39.7.1485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Compound 2242, also known as 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine, is the first known antivirally active nucleoside analog with the side chain substituted at the N-7 position of the purine ring system. Our purpose was to evaluate its retinal toxicity and assess the efficacy of its highest nontoxic concentration in a rabbit model of herpes simplex retinitis. Concentrations of the drug from 0.5 to 2,000 microM were injected intravitreally in twelve New Zealand White rabbits. Fundoscopic, histologic, and electrophysiologic data revealed no evidence of toxicity even at the highest dose of the compound. Dutch pigmented rabbits (n = 34) had their left eyes injected with herpes simplex virus type 1 3 days after, concurrently, or 3 days before intravitreal injection of either 2,000 microM compound 2242 or 480 microM ganciclovir (final concentration in the eye). Both compound 2242 and ganciclovir were equally effective compared with saline when administered simultaneously with the virus (P < 0.0001). In the 3-day pretreatment paradigm, compound 2242 was superior to ganciclovir (P < 0.04), but there was no clear difference between the two with regard to their effects on an established infection. The pharmacokinetics of compound 2242 in 10 rabbits injected intravitreally with 30 microM showed an intravitreal half-life of 8 h. This compound, which may be orally active in its pro form, has a very high therapeutic index in the eye and is more efficient than ganciclovir in this animal model of herpes retinitis.
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Affiliation(s)
- G Besen
- Department of Ophthalmology, University of California at San Diego School of Medicine, La Jolla 92093-0946, USA
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33
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Andrei G, Snoeck R, De Clercq E. Susceptibilities of several drug-resistant herpes simplex virus type 1 strains to alternative antiviral compounds. Antimicrob Agents Chemother 1995; 39:1632-5. [PMID: 7492121 PMCID: PMC162798 DOI: 10.1128/aac.39.7.1632] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Resistant herpes simplex virus type 1 strains were obtained under the selective pressure of acyclovir, ganciclovir, bromovinyldeoxyuridine, foscarnet, 2-phosphonylmethoxyehtyl (PME) derivatives of adenine and 2,6-diaminopurine, 3-hydroxy-2-phosphonylmethoxypropyl derivatives of adenine and cytosine, and 2-amino-7-(1,3-dihydroxy-2-propoxymethyl)purine (S2242). The drug susceptibility profiles of resistant strains point to differences in the modes of action of PME and 3-hydroxy-2-phosphonylmethoxypropyl derivatives and common mechanisms of action of foscarnet, S2242, and PME derivatives against herpes simplex virus type 1 replication.
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Affiliation(s)
- G Andrei
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, Belgium
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34
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Neyts J, Jähne G, Andrei G, Snoeck R, Winkler I, De Clercq E. In vivo antiherpesvirus activity of N-7-substituted acyclic nucleoside analog 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine. Antimicrob Agents Chemother 1995; 39:56-60. [PMID: 7695329 PMCID: PMC162484 DOI: 10.1128/aac.39.1.56] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The efficacy of 2-amino-7-[(1,3-dihydroxy-2-propoxy)methyl]purine (S2242) was evaluated in several animal models for herpesvirus infections. Compound S2242 was more effective than acyclovir (i) when administered subcutaneously in a model for herpes simplex virus type 1 (HSV-1)-induced mortality in immunocompetent mice and (ii) when applied topically to hairless (hr/hr) mice that had been infected intracutaneously with HSV-2. In SCID (severe combined immune deficient) mice that had been infected with a thymidine kinase-deficient HSV-1 strain, S2242 (administered subcutaneously at a dosage of 50 mg/kg/day) completely protected against virus-induced mortality whereas foscarnet was less effective and acyclovir had no or little protective effect. Compound S2242 was far more effective than ganciclovir in preventing or delaying murine cytomegalovirus-induced mortality in immunocompetent and SCID mice. The compound was more effective when a given dose was fractionated and administered on subsequent days than when this dose was administered in one single injection. A 5-day treatment course with S2242 (10 and 50 mg/kg/day) for newborn mice that had been infected with a lethal dose of murine cytomegalovirus suppressed virus-induced mortality. Compound S2242 had no inhibitory effect on the growth of weanling (at 50 mg/kg for 5 days) and 3- to 4-week-old mice (at doses of 50 to 200 mg/kg for 6 weeks). However, akin to ganciclovir, compound S2242 significantly reduced testicle weight, testicle morphology, and spermatogenesis.
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Affiliation(s)
- J Neyts
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, Belgium
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