1
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Wiemer AJ. Metabolic Efficacy of Phosphate Prodrugs and the Remdesivir Paradigm. ACS Pharmacol Transl Sci 2020; 3:613-626. [PMID: 32821882 PMCID: PMC7409933 DOI: 10.1021/acsptsci.0c00076] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Indexed: 02/08/2023]
Abstract
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Drugs that contain phosphates (and
phosphonates or phosphinates)
have intrinsic absorption issues and are therefore often delivered
in prodrug forms to promote their uptake. Effective prodrug forms
distribute their payload to the site of the intended target and release
it efficiently with minimal byproduct toxicity. The ability to balance
unwanted payload release during transit with desired release at the
site of action is critical to prodrug efficacy. Despite decades of
research on prodrug forms, choosing the ideal prodrug form remains
a challenge which is often solved empirically. The recent emergency
use authorization of the antiviral remdesivir for COVID-19 exemplifies
a new approach for delivery of phosphate prodrugs by parenteral dosing,
which minimizes payload release during transit and maximizes tissue
payload distribution. This review focuses on the role of metabolic
activation in efficacy during oral and parenteral dosing of phosphate,
phosphonate, and phosphinate prodrugs. Through examining prior structure–activity
studies on prodrug forms and the choices that led to development of
remdesivir and other clinical drugs and drug candidates, a better
understanding of their ability to distribute to the planned site of
action, such as the liver, plasma, PBMCs, or peripheral tissues, can
be gained. The structure–activity relationships described here
will facilitate the rational design of future prodrugs.
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Affiliation(s)
- Andrew J Wiemer
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269, United States.,Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut 06269, United States
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2
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Arimilli M, Kim C, Dougherty J, Mulato A, Oliyai R, Shaw J, Cundy K, Bischofberger N. Synthesis, in Vitro Biological Evaluation and Oral Bioavailability of 9-[2-(Phosphonomethoxy)Propyl]Adenine (PMPA) Prodrugs. ACTA ACUST UNITED AC 2017. [DOI: 10.1177/095632029700800610] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Mn Arimilli
- Gilead Sciences, 333 Lakeside Drive, Foster City, CA 94404, USA
| | - Cu Kim
- Gilead Sciences, 333 Lakeside Drive, Foster City, CA 94404, USA
| | - J Dougherty
- Gilead Sciences, 333 Lakeside Drive, Foster City, CA 94404, USA
| | - A Mulato
- Gilead Sciences, 333 Lakeside Drive, Foster City, CA 94404, USA
| | - R Oliyai
- Gilead Sciences, 333 Lakeside Drive, Foster City, CA 94404, USA
| | - Jp Shaw
- Gilead Sciences, 333 Lakeside Drive, Foster City, CA 94404, USA
| | - Kc Cundy
- Gilead Sciences, 333 Lakeside Drive, Foster City, CA 94404, USA
| | - N Bischofberger
- Gilead Sciences, 333 Lakeside Drive, Foster City, CA 94404, USA
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3
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Naesens L, Snoeck R, Andrei G, Balzarini J, Neyts J, De Clercq E. HPMPC (cidofovir), PMEA (adefovir) and Related Acyclic Nucleoside Phosphonate Analogues: A Review of their Pharmacology and Clinical Potential in the Treatment of Viral Infections. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/095632029700800101] [Citation(s) in RCA: 184] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The acyclic nucleoside phosphonate (ANP) analogues are broad-spectrum antiviral agents, with potent and selective antiviral activity in vitro and in vivo. The prototype compounds are: ( S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC, cidofovir), which is active against a wide variety of DNA viruses; 9-(2-phosphonylmethoxyethyl)adenine (PMEA, adefovir), which is active against retro-, herpes- and hepadnaviruses, and ( R)-9-(2-phosphonylmethoxypropyl) adenine (PMPA), which is active against retro- and hepadnaviruses. The antiviral action of the ANP analogues is based on a specific interaction of the active diphosphorylated metabolite with the viral DNA polymerase. The long intracellular half-life of the active metabolite accounts for the optimal efficacy in infrequent dosing schedules. The potential of HPMPC as a broad-spectrum anti-DNA virus agent, as originally observed in vitro and in vivo, has been confirmed in clinical trials. HPMPC has recently been commercially released in the USA for the treatment of cytomegalovirus retinitis in AIDS patients. In addition, topical systemic HPMPC is being (or will be) explored for use against other herpesviruses (i.e. herpes simplex virus, Epstein-Barr virus, or varicella-zoster virus), by adenoviruses, or by human papilloma- or polyomaviruses. Intravenous HPMPC is associated with dose-dependent nephrotoxicity, that should be counteracted by prehydration and concomitant administration of probenecid, and by the application of an infrequent dosing schedule. The oral prodrug of PMEA, bis(pivaloyloxymethyl)-PMEA, is currently being evaluated in patients infected with human immunodeficiency virus (HIV) or hepatitis B virus. Finally, preclinical data on the efficacy of PMPA in animal retrovirus models point to its potential usefulness against HIV infections, when given either prophylactically or therapeutically in the treatment of established HIV infections.
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Affiliation(s)
- L Naesens
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
| | - R Snoeck
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
| | - G Andrei
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
| | - J Balzarini
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
| | - J Neyts
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
| | - E De Clercq
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
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4
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Takamatsu Y, Tanaka Y, Kohgo S, Murakami S, Singh K, Das D, Venzon DJ, Amano M, Higashi-Kuwata N, Aoki M, Delino NS, Hayashi S, Takahashi S, Sukenaga Y, Haraguchi K, Sarafianos SG, Maeda K, Mitsuya H. 4'-modified nucleoside analogs: potent inhibitors active against entecavir-resistant hepatitis B virus. Hepatology 2015; 62:1024-36. [PMID: 26122273 PMCID: PMC4589464 DOI: 10.1002/hep.27962] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 06/24/2015] [Indexed: 12/23/2022]
Abstract
UNLABELLED Certain nucleoside/nucleotide reverse transcriptase (RT) inhibitors (NRTIs) are effective against human immunodeficiency virus type 1 (HIV-1) and hepatitis B virus (HBV). However, both viruses often acquire NRTI resistance, making it crucial to develop more-potent agents that offer profound viral suppression. Here, we report that 4'-C-cyano-2-amino-2'-deoxyadenosine (CAdA) is a novel, highly potent inhibitor of both HBV (half maximal inhibitory concentration [IC50 ] = 0.4 nM) and HIV-1 (IC50 = 0.4 nM). In contrast, the approved anti-HBV NRTI, entecavir (ETV), potently inhibits HBV (IC50 = 0.7 nM), but is much less active against HIV-1 (IC50 = 1,000 nM). Similarly, the highly potent HIV-1 inhibitor, 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA; IC50 = 0.3 nM) is less active against HBV (IC50 = 160 nM). Southern analysis using Huh-7 cells transfected with HBV-containing plasmids demonstrated that CAdA was potent against both wild-type (IC50 = 7.2 nM) and ETV-resistant HBV (IC50 = 69.6 nM for HBVETV-RL180M/S202G/M204V), whereas ETV failed to reduce HBVETV-RL180M/S202G/M204V DNA even at 1 μM. Once-daily peroral administration of CAdA reduced HBVETV-RL180M/S202G/M204V viremia (P = 0.0005) in human-liver-chimeric/ HBVETV-RL180M/S202G/M204V-infected mice, whereas ETV completely failed to reduce HBVETV-RL180M/S202G/M204V viremia. None of the mice had significant drug-related body-weight or serum human-albumin concentration changes. Molecular modeling suggests that a shallower HBV-RT hydrophobic pocket at the polymerase active site can better accommodate the slightly shorter 4'-cyano of CAdA-triphosphate (TP), but not the longer 4'-ethynyl of EFdA-TP. In contrast, the deeper HIV-1-RT pocket can efficiently accommodate the 4'-substitutions of both NRTIs. The ETV-TP's cyclopentyl ring can bind more efficiently at the shallow HBV-RT binding pocket. CONCLUSION These data provide insights on the structural and functional associations of HBV- and HIV-1-RTs and show that CAdA may offer new therapeutic options for HBV patients.
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Affiliation(s)
- Yuki Takamatsu
- Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD USA
| | - Yasuhito Tanaka
- Department of Virology & Liver unit, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Satoru Kohgo
- Research Institute & Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan,Department of Pharmaceutical Sciences, Nihon Pharmaceutical University, Saitama, Japan
| | - Shuko Murakami
- Department of Virology & Liver unit, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Kamalendra Singh
- Molecular Microbiology & Immunology, Biochemistry, School of Medicine and Bond Life Sciences Center, University of Missouri, Columbia MO
| | - Debananda Das
- Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD USA
| | - David J. Venzon
- Biostatistics and Data Management Section, National Cancer Institute, National Institutes of Health, Bethesda, MD USA
| | - Masayuki Amano
- Departments of Hematology, Rheumatology, and Clinical Immunology & Infectious Disease, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Nobuyo Higashi-Kuwata
- Research Institute & Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan
| | - Manabu Aoki
- Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD USA,Departments of Hematology, Rheumatology, and Clinical Immunology & Infectious Disease, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan,Department of Medical Technology, Kumamoto Health Science University, Kumamoto, Japan
| | - Nicole S. Delino
- Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD USA
| | - Sanae Hayashi
- Department of Virology & Liver unit, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Satoru Takahashi
- Department of Experimental Pathology & Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yoshikazu Sukenaga
- Research Institute & Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan
| | - Kazuhiro Haraguchi
- Department of Pharmaceutical Sciences, Nihon Pharmaceutical University, Saitama, Japan
| | - Stefan G. Sarafianos
- Molecular Microbiology & Immunology, Biochemistry, School of Medicine and Bond Life Sciences Center, University of Missouri, Columbia MO
| | - Kenji Maeda
- Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD USA,Research Institute & Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan,Correspondence should be addressed to: K.M., Postal address: Kenji Maeda, M.D., Ph.D., Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Tokyo 162-8655, Phone: +81-3-3202-7181 Facsimile: +81-3-3207-1038,
| | - Hiroaki Mitsuya
- Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD USA,Research Institute & Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan,Departments of Hematology, Rheumatology, and Clinical Immunology & Infectious Disease, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
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5
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Česnek M, Jansa P, Šmídková M, Mertlíková-Kaiserová H, Dračínský M, Brust TF, Pávek P, Trejtnar F, Watts VJ, Janeba Z. Bisamidate Prodrugs of 2-Substituted 9-[2-(Phosphonomethoxy)ethyl]adenine (PMEA, adefovir) as Selective Inhibitors of Adenylate Cyclase Toxin from Bordetella pertussis. ChemMedChem 2015; 10:1351-64. [PMID: 26136378 DOI: 10.1002/cmdc.201500183] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Indexed: 11/07/2022]
Abstract
Novel small-molecule agents to treat Bordetella pertussis infections are highly desirable, as pertussis (whooping cough) remains a serious health threat worldwide. In this study, a series of 2-substituted derivatives of 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA, adefovir), in their isopropyl ester bis(L-phenylalanine) prodrug form, were designed and synthesized as potent inhibitors of adenylate cyclase toxin (ACT) isolated from B. pertussis. The series consists of PMEA analogues bearing either a linear or branched aliphatic chain or a heteroatom at the C2 position of the purine moiety. Compounds with a small C2 substituent showed high potency against ACT without cytotoxic effects as well as good selectivity over human adenylate cyclase isoforms AC1, AC2, and AC5. The most potent ACT inhibitor was found to be the bisamidate prodrug of the 2-fluoro PMEA derivative (IC50 =0.145 μM). Although the bisamidate prodrugs reported herein exhibit overall lower activity than the bis(pivaloyloxymethyl) prodrug (adefovir dipivoxil), their toxicity and plasma stability profiles are superior. Furthermore, the bisamidate prodrug was shown to be more stable in plasma than in macrophage homogenate, indicating that the free phosphonate can be effectively distributed to target tissues, such as the lungs. Thus, ACT inhibitors based on acyclic nucleoside phosphonates may represent a new strategy to treat whooping cough.
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Affiliation(s)
- Michal Česnek
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i. Flemingovo nám. 2, 166 10 Prague 6 (Czech Republic)
| | - Petr Jansa
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i. Flemingovo nám. 2, 166 10 Prague 6 (Czech Republic)
| | - Markéta Šmídková
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i. Flemingovo nám. 2, 166 10 Prague 6 (Czech Republic)
| | - Helena Mertlíková-Kaiserová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i. Flemingovo nám. 2, 166 10 Prague 6 (Czech Republic)
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i. Flemingovo nám. 2, 166 10 Prague 6 (Czech Republic)
| | - Tarsis F Brust
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907 (USA)
| | - Petr Pávek
- Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Heyrovského 1203, 500 05 Hradec Králové (Czech Republic).,Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Hněvotínská 5, 775 15 Olomouc (Czech Republic)
| | - František Trejtnar
- Charles University in Prague, Faculty of Pharmacy in Hradec Králové, Heyrovského 1203, 500 05 Hradec Králové (Czech Republic)
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907 (USA)
| | - Zlatko Janeba
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic v.v.i. Flemingovo nám. 2, 166 10 Prague 6 (Czech Republic).
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6
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Pradere U, Garnier-Amblard E, Coats SJ, Amblard F, Schinazi RF. Synthesis of nucleoside phosphate and phosphonate prodrugs. Chem Rev 2014; 114:9154-218. [PMID: 25144792 PMCID: PMC4173794 DOI: 10.1021/cr5002035] [Citation(s) in RCA: 391] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Indexed: 01/29/2023]
Affiliation(s)
- Ugo Pradere
- Center
for AIDS Research, Laboratory of Biochemical Pharmacology, Department
of Pediatrics, Emory University School of
Medicine, and Veterans Affairs Medical Center, Atlanta, Georgia 30322, United States
| | | | | | - Franck Amblard
- Center
for AIDS Research, Laboratory of Biochemical Pharmacology, Department
of Pediatrics, Emory University School of
Medicine, and Veterans Affairs Medical Center, Atlanta, Georgia 30322, United States
| | - Raymond F. Schinazi
- Center
for AIDS Research, Laboratory of Biochemical Pharmacology, Department
of Pediatrics, Emory University School of
Medicine, and Veterans Affairs Medical Center, Atlanta, Georgia 30322, United States
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7
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Ma Z, Zhang W, Wang L, Zhu M, Wang H, Feng WH, Ng TB. A novel compound from the mushroom Cryptoporus volvatus inhibits porcine reproductive and respiratory syndrome virus (PRRSV) in vitro. PLoS One 2013; 8:e79333. [PMID: 24260198 PMCID: PMC3832501 DOI: 10.1371/journal.pone.0079333] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 09/29/2013] [Indexed: 11/20/2022] Open
Abstract
Porcine reproductive and respiratory syndrome (PRRS), caused by PRRS virus (PRRSV), is a serious contagious disease in the swine industry. At present, there are no effective control strategies against PRRSV. Thus, there is an urgent need for new treatment regimens that have efficacious antiviral activity to compensate for vaccines. The anti-infective effect of Cryptoporus volvatus has previously been demonstrated in Tradational Chinese Medicine. In this report, we expected to identify a new anti-PRRSV agent in the aqueous extract of C. volvatus, by employing a combination of modern chromatographic purification techniques and indirect immunofluorescence assay (IFA). Our results showed that C. volvatus extracts from every separation step differed in their inhibitory potency on PRRSV. One anti-PRRSV component designated as CM-H-L-5 was isolated from water-soluble fraction of C. volvatus. The inhibition induced by CM-H-L-5 occurred in a dose-dependent manner. CM-H-L-5 appeared to be a low-molecular-weight polyol fragment with amide groups and carboxylic acid groups. Collectively, our findings imply that CM-H-L-5 from the aqueous extract of C. volvatus has the potential to be used for anti-PRRSV therapy.
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Affiliation(s)
- Zengqiang Ma
- State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing, China
| | - Weiwei Zhang
- State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing, China
| | - Li Wang
- State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing, China
| | - Mengjuan Zhu
- State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing, China
| | - Hexiang Wang
- State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing, China
- * E-mail: (HW); (WF); (TN)
| | - Wen-hai Feng
- State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing, China
- * E-mail: (HW); (WF); (TN)
| | - Tzi Bun Ng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- * E-mail: (HW); (WF); (TN)
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8
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Amidate prodrugs of 9-[2-(phosphonomethoxy)ethyl]adenine as inhibitors of adenylate cyclase toxin from Bordetella pertussis. Antimicrob Agents Chemother 2013; 58:664-71. [PMID: 24145524 DOI: 10.1128/aac.01685-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Adenylate cyclase toxin (ACT) is the key virulence factor of Bordetella pertussis that facilitates its invasion into the mammalian body. 9-[2-(Phosphonomethoxy)ethyl]adenine diphosphate (PMEApp), the active metabolite of the antiviral drug bis(POM)PMEA (adefovir dipivoxil), has been shown to inhibit ACT. The objective of this study was to evaluate six novel amidate prodrugs of PMEA, both phenyloxy phosphonamidates and phosphonodiamidates, for their ability to inhibit ACT activity in the J774A.1 macrophage cell line. The two phenyloxy phosphonamidate prodrugs exhibited greater inhibitory activity (50% inhibitory concentration [IC50] = 22 and 46 nM) than the phosphonodiamidates (IC50 = 84 to 3,960 nM). The inhibitory activity of the prodrugs correlated with their lipophilicity and the degree of their hydrolysis into free PMEA in J774A.1 cells. Although the prodrugs did not inhibit ACT as effectively as bis(POM)PMEA (IC50 = 6 nM), they were significantly less cytotoxic. Moreover, they all reduced apoptotic effects of ACT and prevented an ACT-induced elevation of intracellular [Ca(2+)]i. The amidate prodrugs were less susceptible to degradation in Caco-2 cells compared to bis(POM)PMEA, while they exerted good transepithelial permeability in this assay. As a consequence, a large amount of intact amidate prodrug is expected to be available to target macrophages in vivo. This feature makes nontoxic amidate prodrugs attractive candidates for further investigation as novel antimicrobial agents.
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9
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Roux L, Priet S, Payrot N, Weck C, Fournier M, Zoulim F, Balzarini J, Canard B, Alvarez K. Ester prodrugs of acyclic nucleoside thiophosphonates compared to phosphonates: synthesis, antiviral activity and decomposition study. Eur J Med Chem 2013; 63:869-81. [PMID: 23603046 DOI: 10.1016/j.ejmech.2013.02.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 01/30/2013] [Accepted: 02/26/2013] [Indexed: 12/25/2022]
Abstract
9-[2-(Thiophosphonomethoxy)ethyl]adenine [S-PMEA, 8] and (R)-9-[2-(Thiophosphonomethoxy)propyl]adenine [S-PMPA, 9] are acyclic nucleoside thiophosphonates we described recently that display the same antiviral spectrum (DNA viruses) as approved and potent phosphonates PMEA and (R)-PMPA. Here, we describe the synthesis, antiviral activities in infected cell cultures and decomposition study of bis(pivaloyloxymethoxy)-S-PMEA [Bis-POM-S-PMEA, 13] and bis(isopropyloxymethylcarbonyl)-S-PMPA [Bis-POC-S-PMPA, 14] as orally bioavailable prodrugs of the S-PMEA 8 and S-PMPA 9, in comparison to the equivalent "non-thio" derivatives [Bis-POM-PMEA, 11] and [Bis-POC-PMPA, 12]. Compounds 11, 12, 13 and 14 were evaluated for their in vitro antiviral activity against HIV-1-, HIV-2-, HBV- and a broad panel of DNA viruses, and found to exhibit moderate to potent antiviral activity. In order to determine the decomposition pathway of the prodrugs 11, 12, 13 and 14 into parent compounds PMEA, PMPA, 8 and 9, kinetic data and decomposition pathways in several media are presented. As expected, bis-POM-S-PMEA 13 and bis-POC-S-PMPA 14 behaved as prodrugs of S-PMEA 8 and S-PMPA 9. However, thiophosphonates 8 and 9 were released very smoothly in cell extracts, in contrast to the release of PMEA and PMPA from "non-thio" prodrugs 11 and 12.
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Affiliation(s)
- Loïc Roux
- Laboratoire d'Architecture et Fonction des Macromolécules Biologiques, UMR CNRS 7257, Equipe Chimie Médicinale et Virologie Structurale, Université Aix-Marseille, Parc scientifique de Luminy, 163 av. de Luminy, 13288 Marseille Cedex 9, France
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10
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Kearney BP, Sayre JR, Flaherty JF, Chen SS, Kaul S, Cheng AK. Drug-Drug and Drug-Food Interactions Between Tenofovir Disoproxil Fumarate and Didanosine. J Clin Pharmacol 2013; 45:1360-7. [PMID: 16291710 DOI: 10.1177/0091270005281351] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The drug-drug and drug-food interactions between tenofovir DF and didanosine EC were evaluated in 2 pharmacokinetic studies in healthy adult subjects. When 400 mg was dosed with tenofovir DF, mean didanosine AUC was increased by 44% to 60% following fasted or fed administration. Staggered coadministration (2 hour, fasted) of a reduced didanosine dose of 250 mg resulted in equivalent didanosine exposure, while simultaneous administration with tenofovir DF in the fasted and fed state resulted in didanosine AUCs similar to that of the reference treatment of 400 mg alone in the fasted state. These data indicate that a dose reduction of didanosine is warranted when it is used with tenofovir DF. The drug-drug-food interaction of didanosine may offer more flexible dosing of didanosine EC when it is used with tenofovir DF. Patients receiving tenofovir DF and didanosine together should be carefully monitored for safety and efficacy.
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Affiliation(s)
- Brian P Kearney
- Gilead Sciences, Inc, 333 Lakeside Drive, Foster City, CA 94404, USA
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11
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Pertusat F, Serpi M, McGuigan C. Medicinal Chemistry of Nucleoside Phosphonate Prodrugs for Antiviral Therapy. ACTA ACUST UNITED AC 2012; 22:181-203. [DOI: 10.3851/imp2012] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2011] [Indexed: 10/15/2022]
Abstract
Considerable attention has been focused on the development of phosphonate-containing drugs for application in many therapeutic areas. However, phosphonate diacids are deprotonated at physiological pH and thus phosphonate-containing drugs are not ideal for oral administration, an extremely desirable requisite for the treatment of chronic diseases. To overcome this limitation several prodrug structures of biologically active phosphonate analogues have been developed. The rationale behind the design of such agents is to achieve temporary blockade of the free phosphonic functional group until their systemic absorption and delivery, allowing the release of the active drug only once at the target. In this paper, an overview of acyclic and cyclic nucleoside phosphonate prodrugs, designed as antiviral agents, is presented.
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Affiliation(s)
| | - Michaela Serpi
- Welsh School of Pharmacy, Cardiff University, Cardiff, UK
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12
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Ray AS, Hostetler KY. Application of kinase bypass strategies to nucleoside antivirals. Antiviral Res 2011; 92:277-91. [PMID: 21878354 DOI: 10.1016/j.antiviral.2011.08.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/17/2011] [Accepted: 08/17/2011] [Indexed: 12/19/2022]
Abstract
Nucleoside and nucleotide analogs have served as the cornerstones of antiviral therapy for many viruses. However, the requirement for intracellular activation and side-effects caused by distribution to off-target sites of toxicity still limit the efficacy of the current generation of drugs. Kinase bypass strategies, where phosphorylated nucleosides are delivered directly into cells, thereby, removing the requirement for enzyme catalyzed phosphorylation steps, have already changed the face of antiviral therapy in the form of the acyclic nucleoside phosphonates, cidofovir, adefovir (given orally as its dipivoxil prodrug) and tenofovir (given orally as its disoproxil prodrug), currently used clinically. These strategies hold further promise to advance the field of antiviral therapy with at least 10 kinase bypass and tissue targeted prodrugs, representing seven distinct prodrug classes, currently in clinical trials. This article reviews the history of kinase bypass strategies applied to nucleoside antivirals and the evolution of different tissue targeted prodrug strategies, highlighting clinically relevant examples.
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Affiliation(s)
- Adrian S Ray
- Gilead Sciences, Inc., Foster City, CA 94404, USA.
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13
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Oh CH, Liu LJ, Hong JH. Design and synthesis of dually branched 5'-norcarbocyclic adenosine phosphonodiester analogue as a new anti-HIV prodrug. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2011; 29:721-33. [PMID: 20924954 DOI: 10.1080/15257770.2010.509645] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A novel 3',4'-dimethyl-5'-norcarbocyclic adenosine phosphonic acid was prepared using acyclic stereoselective route from 4-hydroxybutan-2-one (4). To improve the cellular permeability and enhance the anti-HIV activity of this phosphonic acid, a (bis)SATE phosphonodiester nucleoside prodrug (20) was prepared and its chemical stability was evaluated. The newly synthesized bis(SATE) analogue (20) and its parent nucleoside phosphonic acid (18) were assayed for anti-HIV activity using an in vitro assay system in a CEM cell line.
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Affiliation(s)
- Chang Hyun Oh
- Medicinal Chemistry Research Center, Korea Institute of Science and Technology, Seoul, Republic of Korea
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14
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Li H, Hong JH. Synthesis and anti-HIV evaluation of new acyclic phosphonate nucleotide analogues and their bis(SATE) derivatives. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2010; 29:581-90. [PMID: 20661812 DOI: 10.1080/15257770.2010.495958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
This article describes a very simple route for synthesizing novel lipophilic phosphonate bis(t-bu-SATE) prodrugs of acyclic cyclopentenylated nucleosides such as adenine 17 and cytosine 18. The key intermediate 6 was constructed via a ring-closing metathesis of compound 5, which could be readily prepared from diethylmalonate 4. The chemical stability of the bis(SATE) derivatives was tested at neutral (pH = 7.2) and slightly acid (milli-Q water, pH = 5.5) pH. The synthesized compounds were evaluated as potential antiviral agents against HIV-1 virus.
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Affiliation(s)
- Hua Li
- BK-21 Project Team, College of Pharmacy, Chosun University, Kwangju, Republic of Korea
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15
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Karla PK, Quinn TL, Herndon BL, Thomas P, Pal D, Mitra A. Expression of multidrug resistance associated protein 5 (MRP5) on cornea and its role in drug efflux. J Ocul Pharmacol Ther 2009; 25:121-32. [PMID: 19323627 DOI: 10.1089/jop.2008.0084] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE The purpose of this manuscript is to investigate the presence of nucleoside/nucleotide efflux transporter in cornea and to evaluate the role in ocular drug efflux. METHODS RT-PCR, immunoprecipitation followed by Western blot analysis and immunostaining were employed to establish molecular presence of multidrug resistance associated protein 5 (MRP5) on cornea. Corneal efflux by MRP5 was studied with bis(POM)-PMEA and acyclovir using rabbit and human corneal epithelial cells along with MRP5 over expressing cells (MDCKII-MRP5). Ex vivo studies using excised rabbit cornea and in vivo ocular microdialysis in male New Zealand white rabbits were used to further evaluate the role of MRP5 in conferring ocular drug resistance. RESULTS RT-PCR confirms the expression of MRP5 in both rabbit and human corneal epithelial cells along with MDCKII-MRP5 cells. Immunoprecipitation followed by Western blot analysis using a rat (M511-54) monoclonal antibody that reacts with human epitope confirms the expression of MRP5 protein in human corneal epithelial cells and MDCKII-MRP5 cells. Immunostaining performed on human cornea indicates the localization of this efflux pump on both epithelium and endothelium. Efflux studies reveal that depletion of ATP decreased PMEA efflux significantly. MRP5 inhibitors also diminished PMEA and acyclovir efflux. However, depletion of glutathione did not alter efflux. MDR1 and MRP2 did not contribute to PMEA efflux. However, MRP2 is involved in acyclovir efflux while MDR1 do not participate in this process. TLC/autoradiography suggested the conversion of bis(POM)-PMEA to PMEA in rabbit and human corneal epithelial cells. Two well known antiglaucoma drugs, bimatoprost and latanoprost were rapidly effluxed by MRP5. Ex vivo study on intact rabbit corneas demonstrated accumulation of PMEA in cornea in the presence of ATP-depleting medium. In vivo ocular pharmacokinetics also revealed a significant increase in maximum aqueous humor concentration (C(max)) and area under the aqueous humor time curve (AUC) of acyclovir in the presence of MK-571, a specific MRP inhibitor. CONCLUSIONS Taken together immunolocalization on human cornea, in vitro efflux in human, rabbit corneal and MRP5 over expressing cells, ex vivo and in vivo studies in intact rabbit cornea suggest that MRP5 on cornea can significantly lower the permeability of antiviral and glaucoma drugs. These findings may be valuable in developing formulation strategies to optimize ocular bioavailability of topically administered ocular agents.
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Affiliation(s)
- Pradeep K Karla
- University of Missouri at Kansas City, Pharmaceutical Sciences, Kansas City, Missouri 64112, USA
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16
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Abla N, Chinn LW, Nakamura T, Liu L, Huang CC, Johns SJ, Kawamoto M, Stryke D, Taylor TR, Ferrin TE, Giacomini KM, Kroetz DL. The human multidrug resistance protein 4 (MRP4, ABCC4): functional analysis of a highly polymorphic gene. J Pharmacol Exp Ther 2008; 325:859-68. [PMID: 18364470 DOI: 10.1124/jpet.108.136523] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
ABCC4 encodes multidrug resistance protein 4 (MRP4), a member of the ATP-binding cassette family of membrane transporters involved in the efflux of endogenous and xenobiotic molecules. The aims of this study were to identify single nucleotide polymorphisms of ABCC4 and to functionally characterize selected nonsynonymous variants. Resequencing was performed in a large ethnically diverse population. Ten nonsynonymous variants were selected for analysis of transport function based on allele frequencies and evolutionary conservation. The reference and variant MRP4 cDNAs were constructed by site-directed mutagenesis and transiently transfected into human embryonic kidney cells (HEK 293T). The function of MRP4 variants was compared by measuring the intracellular accumulation of two antiviral agents, azidothymidine (AZT) and adefovir (PMEA). A total of 98 variants were identified in the coding and flanking intronic regions of ABCC4. Of these, 43 variants are in the coding region, and 22 are nonsynonymous. In a functional screen of ten variants, there was no evidence for a complete loss of function allele. However, two variants (G187W and G487E) showed a significantly reduced function compared to reference with both substrates, as evidenced by higher intracellular accumulation of AZT and PMEA compared to the reference MRP4 (43 and 69% increase in accumulation for G187W compared with the reference MRP4, with AZT and PMEA, respectively). The G187W variant also showed decreased expression following transient transfection of HEK 293T cells. Further studies are required to assess the clinical significance of this altered function and expression and to evaluate substrate specificity of this functional change.
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Affiliation(s)
- Nada Abla
- Department of Biopharmaceutical Sciences, University of California, San Francisco, California, USA
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17
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Tang YB, Peng ZG, Liu ZY, Li YP, Jiang JD, Li ZR. Some new acyclic nucleotide analogues as antiviral prodrugs: synthesis and bioactivities in vitro. Bioorg Med Chem Lett 2007; 17:6350-3. [PMID: 17888662 DOI: 10.1016/j.bmcl.2007.08.065] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Revised: 08/22/2007] [Accepted: 08/28/2007] [Indexed: 11/23/2022]
Abstract
A series of ester analogues of acyclic nucleotide PMPA and PMEA were synthesized as potent antiviral agents. The antiviral evaluation results indicated that bis benzyl ester prodrug of PMPA 5f and bis allyl ester prodrug of PMEA 5g exhibited potent antiviral activities. The IC(50) of 5f for HBV was 2.15 microM, and the IC(50) of 5g for HIV-1 was 1.61 microM.
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Affiliation(s)
- Yan-bo Tang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, PR China
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18
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Vela JE, Olson LY, Huang A, Fridland A, Ray AS. Simultaneous quantitation of the nucleotide analog adefovir, its phosphorylated anabolites and 2'-deoxyadenosine triphosphate by ion-pairing LC/MS/MS. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 848:335-43. [PMID: 17101307 DOI: 10.1016/j.jchromb.2006.10.063] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 09/21/2006] [Accepted: 10/28/2006] [Indexed: 11/24/2022]
Abstract
The nucleotide analog adefovir is an important therapy for hepatitis B viral infection. The study of nucleoside/tide pharmacology has been hampered by difficulties encountered when trying to develop LC/MS/MS methods for these polar analytes. In an attempt to identify a more convenient, selective and sensitive alternative to the analysis of the metabolism of radiolabeled parent nucleotide traditionally used for in vitro cell culture studies, an LC/MS/MS method was developed for the quantitative detection of adefovir and its phosphorylated metabolites in cellular samples. Ion-pairing reversed phase LC using tetrabutylammonium (TBA) and ammonium phosphate had the best compromise between chromatographic separation and positive mode MS/MS detection. Using microbore reverse phase columns and a low flow acetonitrile gradient it was possible to quantitate adefovir, its metabolites and 2'-deoxyadenosine triphosphate. A cross-validation showed comparable levels of adefovir and its metabolites were determined using either LC/MS/MS or radioactivity detection. However, initial methods were conducted at high pH and utilized an acetonitrile step gradient causing unacceptable column life and unpredictable equilibration. Further method optimization lowered the concentration of TBA and phosphate, decreased pH and applied a linear gradient of acetonitrile. This work resulted in a method that was found to have sensitivity, accuracy and precision sufficient to be a useful tool in the study of the intracellular pharmacology of adefovir in vitro and may be more broadly applicable.
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Augustijns P, Annaert P, Adriaens S, Clercq ED, Kinget R. High Speed HPLC Determination of Bis(Pivaloyloxymethyl)-PMEA and Its Degradation Products, Mono(POM)-PMEA and PMEA. J LIQ CHROMATOGR R T 2006. [DOI: 10.1080/10826079608017156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- P. Augustijns
- a Galenical and Clinical Pharmacy , Katholieke Universiteit Leuven , B-3000, Leuven , Belgium
| | - P. Annaert
- a Galenical and Clinical Pharmacy , Katholieke Universiteit Leuven , B-3000, Leuven , Belgium
| | - S. Adriaens
- a Galenical and Clinical Pharmacy , Katholieke Universiteit Leuven , B-3000, Leuven , Belgium
| | - E. De Clercq
- b Rega Institute for Medical Research Katholieke Universiteit Leuven , B-3000, Leuven , Belgium
| | - R. Kinget
- a Galenical and Clinical Pharmacy , Katholieke Universiteit Leuven , B-3000, Leuven , Belgium
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20
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Lee WA, Martin JC. Perspectives on the development of acyclic nucleotide analogs as antiviral drugs. Antiviral Res 2006; 71:254-9. [PMID: 16837073 DOI: 10.1016/j.antiviral.2006.05.020] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 05/31/2006] [Accepted: 05/31/2006] [Indexed: 10/24/2022]
Abstract
The development of Viread (tenofovir disoproxil) for HIV and Hepsera (adefovir dipivoxil) for HBV presented many unique challenges. Unlike nucleosides and most conventional drugs, the parent acyclic nucleotide analogs are charged at physiologic pH and not suitable for oral administration which is highly desired in chronic therapies. Physicochemical properties, cellular permeation, renal toxicity, and bioavailability all had to be addressed during the development of these compounds. As a class, the acyclic nucleotides have long intracellular half-lives, allowing once-daily dosing, which provided the initial rationale for treatment of chronic viral diseases such as HIV and HBV. Prodrugs originally designed to deliver the parent acyclic nucleotide analog to the systemic circulation, also function to increase the tissue distribution and intracellular concentrations of the acyclic nucleotide diphosphate inside cells.
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Affiliation(s)
- William A Lee
- Gilead Sciences, Inc., 333 Lakeside Drive, Foster City, CA 94404, USA.
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21
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Meier C. cyclo
Sal Phosphates as Chemical Trojan Horses for Intracellular Nucleotide and Glycosylmonophosphate Delivery — Chemistry Meets Biology. European J Org Chem 2006. [DOI: 10.1002/ejoc.200500671] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Chris Meier
- Institute of Organic Chemistry, University of Hamburg, Martin‐Luther‐King‐Platz 6, 20146 Hamburg, Germany, Fax: +49‐40‐42838‐2495
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22
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Meier C, Görbig U, Müller C, Balzarini J. cycloSal-PMEA and cycloAmb-PMEA: potentially new phosphonate prodrugs based on the cycloSal-pronucleotide approach. J Med Chem 2006; 48:8079-86. [PMID: 16335932 DOI: 10.1021/jm050641a] [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] [Indexed: 11/29/2022]
Abstract
Two new classes of lipophilic prodrugs of the antiviral active phosphonate 9-[2-phosphonomethoxyethyl]adenine (PMEA 1) have been prepared and were studied with regard to their hydrolysis properties and biological activity. A first series of compounds was prepared on the basis of the cycloSal nucleotide approach. Because of the surprisingly low hydrolysis stability of these cycloSal-PMEA derivatives, more stable derivatives have to be developed. Instead of using salicyl alcohol, in cycloAmb-PMEA derivatives 2-aminobenzyl alcohols were attached to PMEA 1. The latter compounds showed a considerably higher stability compared to the cycloSal counterparts. Stability studies revealed that all lipophilic prodrugs delivered PMEA selectively by chemical means. All compounds proved to be noninhibiting to acetyl- and butyrylcholinesterase, and some of the phosphonate diesters were found to be more active against HIV compared to the parent PMEA.
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Affiliation(s)
- Chris Meier
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg, Germany.
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McColl DJ, Margot NA, Wulfsohn M, Coakley DF, Cheng AK, Miller MD. Patterns of resistance emerging in HIV-1 from antiretroviral-experienced patients undergoing intensification therapy with tenofovir disoproxil fumarate. J Acquir Immune Defic Syndr 2005; 37:1340-50. [PMID: 15483463 DOI: 10.1097/00126334-200411010-00002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Study GS-99-907 was a 48-week, phase 3, double-blind, placebo-controlled intensification trial of tenofovir disoproxil fumarate (tenofovir DF). Antiretroviral-experienced patients added tenofovir DF 300 mg once daily to their existing regimen. The patterns of HIV-1 resistance development and the corresponding virologic responses were evaluated in a virology substudy at week 48. Although 94% of these treatment-experienced patients had nucleoside-associated resistance mutations (NAMs) at baseline, addition of tenofovir DF resulted in a mean reduction in viral load of -0.59 log10 copies/mL after 24 weeks that was durable through 48 weeks. Relative to the placebo-controlled arm, patients in the tenofovir DF arm had a reduced frequency of development of resistance mutations to all classes of HIV-1 inhibitors, with reduction in new protease inhibitor (PI)-associated mutations achieving statistical significance. The K65R mutation, which occurred in 8 patients (3%), was the only emergent mutation directly associated with tenofovir DF therapy. New thymidine analogue-associated mutations (TAMs) emerged in 19% of patients by week 48. Other than K65R, the patterns of mutations that developed were not significantly different between the tenofovir DF and placebo control arms, suggesting that the background therapies caused their development. The K65R mutation emerged only in patients with no detectable TAMs at baseline, whereas new TAMs developed similarly between patients with or without TAMs at baseline. Development of K65R was associated with mostly low-level changes in phenotypic susceptibility to tenofovir DF and other nucleoside reverse transcriptase inhibitors and was not associated with viral load rebound. No novel patterns of genotypic or phenotypic resistance to tenofovir were identified. Therefore, intensification with once-daily tenofovir DF therapy resulted in a sustained reduction in HIV-1 viral load and a low risk for development of the K65R mutation in this treatment-experienced patient population.
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Tian Q, Zhang J, Tan TMC, Chan E, Duan W, Chan SY, Boelsterli UA, Ho PCL, Yang H, Bian JS, Huang M, Zhu YZ, Xiong W, Li X, Zhou S. Human Multidrug Resistance Associated Protein 4 Confers Resistance to Camptothecins. Pharm Res 2005; 22:1837-53. [PMID: 16132345 DOI: 10.1007/s11095-005-7595-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Accepted: 07/22/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE The multidrug resistance associated protein (MRP) 4 is a member of the adenosine triphosphate (ATP)-binding cassette transporter family. Camptothecins (CPTs) have shown substantial anticancer activity against a broad spectrum of tumors by inhibiting DNA topoisomerase I, but tumor resistance is one of the major reasons for therapeutic failure. P-glycoprotein, breast cancer resistance protein, MRP1, and MRP2 have been implicated in resistance to various CPTs including CPT-11 (irinotecan), SN-38 (the active metabolite of CPT-11), and topotecan. In this study, we explored the resistance profiles and intracellular accumulation of a panel of CPTs including CPT, CPT-11, SN-38, rubitecan, and 10-hydroxy-CPT (10-OH-CPT) in HepG2 cells with stably overexpressed human MRP4. Other anticancer agents such as paclitaxel, cyclophosphamide, and carboplatin were also included. METHODS HepG2 cells were transfected with an empty vehicle plasmid (V/HepG2) or human MRP4 (MRP4/HepG2). The resistance profiles of test drugs in exponentially growing V/HepG2 and MRP4/HepG2 cells were examined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazonium bromide (MTT) assay with 4 or 48 h exposure time of the test drug in the absence or presence of various MRP4 inhibitors. The accumulation of CPT-11, SN-38, and paclitaxel by V/HepG2 and MRP4/HepG2 cells was determined by validated high-performance liquid chromatography methods. RESULTS Based on the resistance folds from the MTT assay with 48 h exposure time of the test drug, MRP4 conferred resistance to CPTs tested in the order 10-OH-CPT (14.21) > SN-38 carboxylate (9.70) > rubitecan (9.06) > SN-38 lactone (8.91) > CPT lactone (7.33) > CPT-11 lactone (5.64) > CPT carboxylate (4.30) > CPT-11 carboxylate (2.68). Overall, overexpression of MRP4 increased the IC50 values 1.78- to 14.21-fold for various CPTs in lactone or carboxylate form. The resistance of MRP4 to various CPTs tested was significantly reversed in the presence of dl-buthionine-(S,R)-sulfoximine (BSO, a gamma-glutamylcysteine synthetase inhibitor), MK571, celecoxib, or diclofenac (all MRP4 inhibitors). In addition, the accumulation of CPT-11 and SN-38 over 120 min in MRP4/HepG2 cells was significantly reduced compared to V/HepG2 cells, whereas the addition of celecoxib, MK571, or BSO significantly increased their accumulation in MRP4/HepG2 cells. There was no significant difference in the intracellular accumulation of paclitaxel in V/HepG2 and MRP4/HepG2 cells, indicating that P-glycoprotein was not involved in the observed resistance to CPTs in this study. MRP4 also conferred resistance to cyclophosphamide and this was partially reversed by BSO. However, MRP4 did not increase resistance to paclitaxel, carboplatin, etoposide (VP-16), 5-fluorouracil, and cyclosporine. CONCLUSIONS Human MRP4 rendered significant resistance to cyclophosphamide, CPT, CPT-11, SN-38, rubitecan, and 10-OH-CPT. CPT-11 and SN-38 are substrates for MRP4. Further studies are needed to explore the role of MRP4 in resistance, toxicity, and pharmacokinetics of CPTs and cyclophosphamide.
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Affiliation(s)
- Quan Tian
- Department of Pharmacy, Faculty of Science, National University of Singapore, Science Drive 4, Singapore 117543, Singapore
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Lee WA, He GX, Eisenberg E, Cihlar T, Swaminathan S, Mulato A, Cundy KC. Selective intracellular activation of a novel prodrug of the human immunodeficiency virus reverse transcriptase inhibitor tenofovir leads to preferential distribution and accumulation in lymphatic tissue. Antimicrob Agents Chemother 2005; 49:1898-906. [PMID: 15855512 PMCID: PMC1087627 DOI: 10.1128/aac.49.5.1898-1906.2005] [Citation(s) in RCA: 263] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
An isopropylalaninyl monoamidate phenyl monoester prodrug of tenofovir (GS 7340) was prepared, and its in vitro antiviral activity, metabolism, and pharmacokinetics in dogs were determined. The 50% effective concentration (EC(50)) of GS 7340 against human immunodeficiency virus type 1 in MT-2 cells was 0.005 microM compared to an EC(50) of 5 microM for the parent drug, tenofovir. The (L)-alaninyl analog (GS 7340) was >1,000-fold more active than the (D)-alaninyl analog. GS 7340 has a half-life of 90 min in human plasma at 37 degrees C and a half-life of 28.3 min in an MT-2 cell extract at 37 degrees C. The antiviral activity (>10 x the EC(50)) and the metabolic stability in MT-2 cell extracts (>35 x) and plasma (>2.5 x) were also sensitive to the stereochemistry at the phosphorus. After a single oral dose of GS 7340 (10 mg-eq/kg tenofovir) to male beagle dogs, the plasma bioavailability of tenofovir compared to an intravenous dose of tenofovir was 17%. The total intracellular concentration of all tenofovir species in isolated peripheral blood mononuclear cells at 24 h was 63 microg-eq/ml compared to 0.2 microg-eq/ml in plasma. A radiolabeled distribution study with dogs resulted in an increased distribution of tenofovir to tissues of lymphatic origin compared to the commercially available prodrug tenofovir DF (Viread).
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Affiliation(s)
- William A Lee
- Gilead Sciences, Inc., 333 Lakeside Dr., Foster City, CA 94404, USA.
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26
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Chanteux H, Van Bambeke F, Mingeot-Leclercq MP, Tulkens PM. Accumulation and oriented transport of ampicillin in Caco-2 cells from its pivaloyloxymethylester prodrug, pivampicillin. Antimicrob Agents Chemother 2005; 49:1279-88. [PMID: 15793098 PMCID: PMC1068589 DOI: 10.1128/aac.49.4.1279-1288.2005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pivampicillin (PIVA), an acyloxymethylester of ampicillin, is thought to enhance the oral bioavailability of ampicillin because of its greater lipophilicity compared to that of ampicillin. The fate of PIVA in intestinal cells and the exact location of its conversion into ampicillin have, however, never been unambiguously established. Polarized Caco-2 cells have been used to examine the handling of PIVA and the release of ampicillin from PIVA by the intestinal epithelium. Experiments were limited to 3 h. Cells incubated with PIVA (apical pole) showed a fast accumulation of ampicillin and transport toward the basolateral medium, whereas PIVA itself was only poorly accumulated and transported. Cells incubated with free ampicillin accumulated and transported only minimal amounts of this drug. Release of ampicillin from cells incubated with PIVA was unaffected by PEPT1 and OCTN2 inhibitors but was sharply decreased after ATP depletion or addition of bis(4-nitrophenyl)-phosphate (BNPP; an esterase inhibitor). PIVA incubated with Caco-2 lysates released free ampicillin, and this release was inhibited by BNPP. Efflux studies showed that the ampicillin that accumulated in cells after incubation with PIVA was preferentially transported out of the cells through the basolateral pole. This efflux was decreased by multidrug resistance-associated protein (MRP) inhibitors (probenecid, MK-571) and by ATP depletion. A phthalimidomethylester of ampicillin that resists cellular esterases failed to cause any significant release (cell lysate) or transport (polarized Caco-2 cells) of ampicillin. These results show that when PIVA is given to Caco-2 cells from their apical pole, ampicillin is released intracellularly and that ampicillin is thereafter preferentially effluxed into the basolateral medium through an MRP-like transporter.
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Affiliation(s)
- Hugues Chanteux
- Unité de pharmacologie cellulaire et moléculaire, Université catholique de Louvain 73-70, Avenue E. Mounier, 73, B-1200 Brussels, Belgium
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Bi HC, Zhong GP, Zhou S, Chen X, Huang M. Determination of adefovir in human plasma by liquid chromatography/tandem mass spectrometry: application to a pharmacokinetic study. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2005; 19:2911-7. [PMID: 16167376 DOI: 10.1002/rcm.2141] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated to determine the concentrations of adefovir [9-(2-phosphonylmethoxyethyl)adenine, PMEA] in human plasma. After one-step protein precipitation of plasma samples by methanol, adefovir was analyzed by LC/MS/MS using positive electrospray ionization. Chromatography was performed on a C18 column. The extraction recoveries of adefovir were found to be 85.1-89.3%. Adefovir was stable under routine laboratory conditions. A minimal matrix effect resulting in a slight ionization enhancement of adefovir (<10.9%) was observed, which did not markedly affect the behavior of the calibrations curves and accuracy and precision data. The method had a chromatographic run time of 7.8 min and a linear calibration curve over the concentration range 1.5-90 ng/mL for adefovir. The lower limit of quantification of the method was 1.5 ng/mL. The intra- and inter-day precision was less than 8.4%. These results indicated that this LC/MS/MS method has high selectivity and efficiency, and acceptable accuracy, precision and sensitivity. The validated LC/MS/MS method has been successfully used in a pharmacokinetic study in healthy volunteers treated with oral adefovir dipivoxil at 10 and 20 mg.
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Affiliation(s)
- Hui-Chang Bi
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, 74 Zhongshan Road II, Guangzhou 510080, China
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Ray AS, Vela JE, Olson L, Fridland A. Effective metabolism and long intracellular half life of the anti-hepatitis B agent adefovir in hepatic cells. Biochem Pharmacol 2004; 68:1825-31. [PMID: 15450948 DOI: 10.1016/j.bcp.2004.07.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Accepted: 07/08/2004] [Indexed: 12/12/2022]
Abstract
Adefovir dipivoxil (ADV) is esterolytically cleaved to the 2'-deoxyadenosine monophosphate (dAMP) analog adefovir, subsequent phosphorylation leads to the formation of the anti-Hepatitis B virus (HBV) agent adefovir-DP. To better understand the mechanism of action of ADV, metabolism studies were done in Hep G2, Huh-7 and primary human hepatocytes. Separation of radiolabeled adefovir metabolites after incubation in Hep G2 cells suggested that adefovir in its mono- and di-phosphorylated forms are the only metabolites formed from adefovir. Incubation of 10 microM adefovir with hepatic cell lines and fresh monolayers of primary human hepatocytes from two donors and analysis of intracellular metabolites by liquid chromatography coupled to tandem mass spectrometry resulted in adefovir-DP levels of approximately 10 pmol/million cells. Adefovir was more efficiently phosphorylated in primary hepatocytes than cell lines with adefovir-DP accounting for 44% versus 26% of total intracellular adefovir after 24 h. Egress studies showed adefovir-DP to have a half-life of 33 +/- 3 h, 10 +/- 1 h, 48 +/- 3 h and 33 +/- 2 h in Hep G2, Huh-7, and primary hepatocytes from two separate donors, respectively. The markedly shorter half-life in Huh-7 cells was inferred to be transport dependent based on its sensitivity to the transport inhibitor MK-571. Effective phosphorylation coupled with a long intracellular half-life and small competing dATP pool sizes in primary hepatocytes forms the cellular metabolic basis for the efficacy of adefovir dipivoxil in the treatment of chronic hepatitis B.
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Affiliation(s)
- Adrian S Ray
- Department of Drug Metabolism, Gilead Sciences, Inc., Foster City, CA 94404, USA.
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Abstract
For the management of HBV infection, an increasing number of nucleotide and nucleoside analogs are active against wild-type HBV and some against HBV with YMDD and other compensatory mutations. Table 2 depicts the IC50 and susceptibilities of HBV to various antiviral agents. The dichotomy between in vitro and in vivo susceptibilities to YMDD mutants is due to a change in IC50 between wild-type and mutant virus. Thus a drug may have less activity in vitro but at doses used in vivo show activity against YMDD and other compensatory mutations. Some HBV drugs share activity against HIV, which may be useful in the co-infected patient. Other nucleoside analogs are in various stages of development, including MCC-478 and DAPD. In the future, clinicians will have a plethora of reagents to chose from, and combination therapies may be invoked.
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Affiliation(s)
- David J Quan
- Department of Clinical Pharmacy, University of California, San Francisco, 521 Parnassus Avenue, Room C-152, Box 0622, San Francisco, CA 94143-0622, USA
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Dallas S, Schlichter L, Bendayan R. Multidrug resistance protein (MRP) 4- and MRP 5-mediated efflux of 9-(2-phosphonylmethoxyethyl)adenine by microglia. J Pharmacol Exp Ther 2004; 309:1221-9. [PMID: 14762102 DOI: 10.1124/jpet.103.063966] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The pathogenesis of human immunodeficiency virus (HIV)-associated dementia has been linked to microglial responses after infection. We have recently confirmed expression of several ATP-dependent efflux transporters in microglia, namely, multidrug resistance protein 1 (MRP1) and P-glycoprotein (P-gp). In the present study, we investigated whether cultured rat microglia express two additional MRP family members, rMRP4 and rMRP5. Using reverse transcriptase-polymerase chain reaction, rMRP4 and rMRP5 mRNA was detected in primary cultures of microglia and in a rat microglia cell line, MLS-9. Western blot analysis further confirmed protein expression of the two MRP isoforms in MLS-9 cells. Bis(pivaloxymethyl)-9-(2-phosphonylmethoxyethyl)adenine [bis(POM)PMEA], a lipophilic ester prodrug of the well characterized MRP4 and 5 substrate 9-(2-phosphonylmethoxyethyl)adenine (PMEA), was chosen to examine transport characteristics in MLS-9. Using thin layer chromatography, we verified that more than 90% of radioactivity recovered in MLS-9 loaded with 1 microM [(3)H]bis(POM)PMEA for 1 h under ATP-depleting conditions was converted to PMEA. Efflux of PMEA by MLS-9 cell monolayers was ATP-dependent, glutathione-independent, and significantly inhibited by several MRP inhibitors (i.e., sulfinpyrazone, genistein, indomethacin, and probenecid) as well as the antiretroviral drug azidothymidine-monophosphate. Similar results were not observed in MRP1- or P-gp-overexpressing cell lines, suggesting that PMEA is not a substrate for either P-gp or MRP1. These studies provide further evidence that microglia express multiple subfamilies of ATP-binding cassette transporters (i.e., P-gp, MRP1, MRP4, and MRP5) that could restrict permeation of several different classes of antiretroviral drugs in a brain cellular target of HIV-1 infection.
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Affiliation(s)
- Shannon Dallas
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 19 Russell St., Toronto, ON M5S 2S2, Canada
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31
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Kamiya N, Kubota A, Iwase Y, Sekiya K, Ubasawa M, Yuasa S. Antiviral activities of MCC-478, a novel and specific inhibitor of hepatitis B virus. Antimicrob Agents Chemother 2002; 46:2872-7. [PMID: 12183240 PMCID: PMC127398 DOI: 10.1128/aac.46.9.2872-2877.2002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
MCC-478 is a newly synthesized 2-amino-6-arylthio-9-phosphonomethoxyethylpurine bis(2,2,2-trifluoroethyl) ester derivative. MCC-478 showed a substantially higher (ca. 80-fold) anti-hepatitis B virus (HBV) activity than that of lamivudine, despite no significant anti-human immunodeficiency virus activity. Since the bis(2,2,2-trifluoroethyl) ester group was used to improve the oral bioavailability of the phosphonomethoxyethylpurine derivatives, two monoester derivatives and one phosphonic acid derivative were also evaluated. It was suggested that these hydrolyzed derivatives, which appeared in animals given MCC-478, have enough anti-HBV activity to contribute to efficacy in vivo. Furthermore, no apparent cytotoxic effects or reductions of mitochondrial DNA content by MCC-478 and its derivatives were observed. These results indicated that MCC-478 may be a new promising anti-HBV agent.
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Affiliation(s)
- Naohiro Kamiya
- Research Laboratory IV, Mitsubishi Pharma Corporation, Yokohama, Japan.
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32
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Turpin JA. Considerations and development of topical microbicides to inhibit the sexual transmission of HIV. Expert Opin Investig Drugs 2002; 11:1077-97. [PMID: 12150703 DOI: 10.1517/13543784.11.8.1077] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The increased incidence of HIV/AIDS disease in women aged 15 - 49 years has identified the urgent need for a female-controlled, efficacious and safe vaginal topical microbicide. To meet this challenge, new topical microbicide candidates consisting of molecules or formulations that modify the genital environment (BufferGel, engineered Lactobacillus, over-the-counter lubricants), surfactants (C31D/Savvy, sodium dodecyl sulfate, sodium lauryl sulfate), polyanionic polymers (PRO 2000, beta-cyclodextrin, Carraguard, CAP, D2S, SPL-7013), proteins (cyanovirin-N, monoclonal antibodies, thromspondin-1 peptides, Pokeweed antiviral protein and others), reverse transcription inhibitors (PMPA [Tenofovir ]), UC-781, SJ-3366, DABO and thiourea) and other molecules (NCp7-specific virucides, chemokine receptor agonists/antagonists, WHI-05 and WHI-07) are currently being investigated for activity, safety and efficacy. This review will assess the development of these molecules in the context of cervicovaginal defences and the clinical failure of nonoxynol-9.
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Affiliation(s)
- Jim A Turpin
- TherImmune Research Corporation, Infectious Disease and Immunology Department, 18761 North Frederick Avenue, Suite A, Gaithersburg, MD 20879, USA.
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Balzarini J, Pannecouque C, De Clercq E, Aquaro S, Perno CF, Egberink H, Holý A. Antiretrovirus activity of a novel class of acyclic pyrimidine nucleoside phosphonates. Antimicrob Agents Chemother 2002; 46:2185-93. [PMID: 12069973 PMCID: PMC127315 DOI: 10.1128/aac.46.7.2185-2193.2002] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel class of acyclic nucleoside phosphonates has been discovered in which the base consists of a pyrimidine preferably containing an amino group at C-2 and C-4 and a 2-(phosphonomethoxy)ethoxy (PMEO) or a 2-(phosphonomethoxy)propoxy (PMPO) group at C-6. The 6-PMEO 2,4-diaminopyrimidine (compound 1) and 6-PMPO 2,4-diaminopyrimidine (compound 11) derivatives showed potent activity against human immunodeficiency virus (HIV) in the laboratory (i.e., CEM and MT-4 cells) and in primary (i.e., peripheral blood lymphocyte and monocyte/macrophage) cell cultures and pronounced activity against Moloney murine sarcoma virus in newborn NMRI mice. Their in vitro and in vivo antiretroviral activity was comparable to that of reference compounds 9-[(2-phosphonomethoxy)ethyl]adenine (adefovir) and (R)-9-[(2-phosphonomethoxy)-propyl]adenine (tenofovir), and the enantiospecificity of (R)- and (S)-PMPO pyrimidine derivatives as regards their antiretroviral activity was identical to that of the classical (R)- and (S)-9-(2-phosphonomethoxy)propyl purine derivatives. The prototype PMEO and PMPO pyrimidine analogues were relatively nontoxic in cell culture and did not markedly interfere with host cell macromolecular (i.e., DNA, RNA, or protein) synthesis. Compounds 1 and 11 should be considered attractive novel pyrimidine nucleotide phosphonate analogues to be further pursued for their potential as antiretroviral agents in the clinical setting.
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Affiliation(s)
- J Balzarini
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium.
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Lee HJ, Cooperwood JS, You Z, Ko DH. Prodrug and antedrug: two diametrical approaches in designing safer drugs. Arch Pharm Res 2002; 25:111-36. [PMID: 12009024 DOI: 10.1007/bf02976552] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The prodrug and antedrug concepts, which were developed to overcome the physical and pharmacological shortcomings of various therapeutic classes of agents, employ diametrically different metabolic transformations. The prodrug undergoes a predictable metabolic activation prior to exhibiting its pharmacological effects in a target tissue while the antedrug undergoes metabolic deactivation in the systemic circulation upon leaving a target tissue. An increased therapeutic index is the aspiration for both approaches in designing as well as evaluation criteria. The recent research endeavors of prodrugs include the gene-directed and antibody-directed enzymatic activation of a molecule in a targeted tissue, organ specific delivery, improved bioavailabilities of nucleosides and cellular penetration of nucleotides. As for antedrugs, emphasis in research has been based upon the design and synthesis of systemically inactive molecule by incorporating a metabolically labile functional group into an active molecule.
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Affiliation(s)
- Henry J Lee
- College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee 32307, USA.
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35
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Ballatore C, McGuigan C, De Clercq E, Balzarini J. Synthesis and evaluation of novel amidate prodrugs of PMEA and PMPA. Bioorg Med Chem Lett 2001; 11:1053-6. [PMID: 11327587 DOI: 10.1016/s0960-894x(01)00128-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Some novel amidate prodrugs of PMEA and PMPA have been synthesised and tested in vitro for their biological activity. Compound 5 in particular showed greatly enhanced antiviral potency compared with the parent nucleotide analogue. In vitro enzymatic studies and structure-activity relationships indicate that the degradation mechanism of such prodrugs may be the same as that described for the phosphoramidate triesters of nucleotide analogues.
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Affiliation(s)
- C Ballatore
- Welsh School of Pharmacy, Cardiff University, UK
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36
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Kim SS, Kothari N, You XJ, Robinson WE, Schnell T, Uberla K, Fan H. Generation of replication-defective helper-free vectors based on simian immunodeficiency virus. Virology 2001; 282:154-67. [PMID: 11259198 DOI: 10.1006/viro.2000.0808] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A systematic study on generating simian immunodeficiency virus (SIV)-based vectors was carried out. The goal was to generate helper-free, replication-defective SIVmac-based vectors at high titers. The general approach was to cotransfect into human 293T cells a plasmid carrying the vector construct along with two helper plasmids that together expressed the SIVmac virion proteins. Initial vectors carried the bacterial beta-galactosidase gene (beta-gal). These vectors had a technical difficulty: "pseudotransduction" of beta-gal protein produced during the 293T cell transfections. As a result, infection of cultures with these vector stocks also resulted in passive transfer into, and X-gal staining of, cells that had not actually been infected by the vector. A second generation of vectors expressing the enhanced jellyfish green fluorescence protein (EGFP) was not subject to this artifact. A systematic study of the SIVmac-based EGFP vectors was carried out. Helper-free vector stocks were obtained when helper plasmids lacking the SIVmac packaging signals were used. By employing envelope helper plasmids derived from different SIVmac isolates, it was possible to generate SIVmac-based vectors pseudotyped with envelope proteins of different cell tropism. Optimization of vector and helper plasmid structures, transfection conditions, and infection procedures ultimately yielded vector titers in excess of 10(6)/ml.
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Affiliation(s)
- S S Kim
- Department of Molecular Biology and Biochemistry, University of California, Irvine 92697, USA
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37
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Kim SS, You XJ, Harmon ME, Overbaugh J, Fan H. Use of helper-free replication-defective simian immunodeficiency virus-based vectors to study macrophage and T tropism: evidence for distinct levels of restriction in primary macrophages and a T-cell line. J Virol 2001; 75:2288-300. [PMID: 11160732 PMCID: PMC114812 DOI: 10.1128/jvi.75.5.2288-2300.2001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cell tropism of human and simian immunodeficiency viruses (HIV and SIV, respectively) is governed in part by interactions between the viral envelope protein and the cellular receptors. However, there is evidence that envelope-host cell interactions also affect postentry steps in viral replication. We used a helper-free replication-defective SIV macaque (SIVmac)-based retroviral vector carrying the enhanced jellyfish green fluorescent protein inserted into the nef region (V1EGFP) to examine SIV tropism in a single cycle of infection. Vector stocks containing envelope proteins from three different SIVmac clones, namely, SIVmac239 (T-lymphocyte tropic [T-tropic]), SIVmac316 (macrophage tropic [M-tropic]), and SIVmac1A11 (dualtropic), were tested. SIVmac239 replicates efficiently in many human T-cell lines, but it does not efficiently infect primary rhesus macrophages. Conversely, SIVmac316 efficiently infects primary macrophages, but it does not replicate in Molt4-Clone8 (M4C8) T cells. SIVmac1A11 replicates efficiently in both cell types. When primary macrophages were infected with V1EGFP pseudotyped by SIVmac316 or SIVmac1A11 envelopes, the infection was substantially (ca. 200- to 300-fold) more efficient than for the SIVmac239 pseudotype. Thus, in primary macrophages, a major component of M versus T tropism involves relatively early events in the infection cycle. Quantitative PCR studies indicated that synthesis and transport of vector DNA into the nucleus were similar for macrophages infected with the clone 239 and 316 pseudotypes, suggesting that the restriction for SIVmac239 infection is after reverse transcription and nuclear import of viral DNA. When the same vector pseudotypes were used to infect M4C8 cells, they all showed approximately equivalent infectivities, even though replication-competent SIVmac316 does not continue to replicate in these cells. Therefore, in M4C8 cells, restriction involves a late step in the infection cycle (after proviral integration and expression). Thus, depending on the cell type infected, envelope-dependent cell interactions that govern SIV M and T tropism may involve different steps in infection.
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Affiliation(s)
- S S Kim
- Department of Molecular Biology and Biochemistry, University of California at Irvine, Irvine, California 92697, USA
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Wijnholds J, Mol CA, van Deemter L, de Haas M, Scheffer GL, Baas F, Beijnen JH, Scheper RJ, Hatse S, De Clercq E, Balzarini J, Borst P. Multidrug-resistance protein 5 is a multispecific organic anion transporter able to transport nucleotide analogs. Proc Natl Acad Sci U S A 2000; 97:7476-81. [PMID: 10840050 PMCID: PMC16570 DOI: 10.1073/pnas.120159197] [Citation(s) in RCA: 358] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two prominent members of the ATP-binding cassette superfamily of transmembrane proteins, multidrug resistance 1 (MDR1) P-glycoprotein and multidrug resistance protein 1 (MRP1), can mediate the cellular extrusion of xenobiotics and (anticancer) drugs from normal and tumor cells. The MRP subfamily consists of at least six members, and here we report the functional characterization of human MRP5. We found resistance against the thiopurine anticancer drugs, 6-mercaptopurine (6-MP) and thioguanine, and the anti-HIV drug 9-(2-phosphonylmethoxyethyl)adenine (PMEA) in MRP5-transfected cells. This resistance is due to an increased extrusion of PMEA and 6-thioinosine monophosphate from the cells that overproduce MRP5. In polarized Madin-Darby canine kidney II (MDCKII) cells transfected with an MRP5 cDNA construct, MRP5 is routed to the basolateral membrane and these cells transport S-(2,4-dinitrophenyl)glutathione and glutathione preferentially toward the basal compartment. Inhibitors of organic anion transport inhibit transport mediated by MRP5. We speculate that MRP5 might play a role in some cases of unexplained resistance to thiopurines in acute lymphoblastic leukemia and/or to antiretroviral nucleoside analogs in HIV-infected patients.
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Affiliation(s)
- J Wijnholds
- Division of Molecular Biology and Center for Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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Hughes WT, Shenep JL, Rodman JH, Fridland A, Willoughby R, Blanchard S, Purdue L, Coakley DF, Cundy KC, Culnane M, Zimmer B, Burchett S, Read JS. Single-dose pharmacokinetics and safety of the oral antiviral compound adefovir dipivoxil in children infected with human immunodeficiency virus type 1. The Pediatrics AIDS Clinical Trials Group. Antimicrob Agents Chemother 2000; 44:1041-6. [PMID: 10722509 PMCID: PMC89810 DOI: 10.1128/aac.44.4.1041-1046.2000] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/1999] [Accepted: 01/10/2000] [Indexed: 11/20/2022] Open
Abstract
The acyclic phosphonate analog adefovir is a potent inhibitor of retroviruses, including human immunodeficiency virus (HIV) type 1, and, unlike some antiviral nucleosides, does not require the initial phosphorylation step for its activity. Two oral dosages of the adefovir prodrug adefovir dipivoxil were evaluated in a phase I study with children with HIV infection. A total of 14 patients were stratified into age groups ranging from 6 months to 18 years of age. Eight patients received 1.5 mg of adefovir dipivoxil per kg of body weight, and six patients received 3.0 mg of adefovir dipivoxil per kg. Serum samples were obtained at intervals during the 8 h postdosing and were analyzed for adefovir concentrations. Patients were monitored for adverse effects. All samples collected resulted in quantifiable levels of adefovir (lower limit of quantitation, 25 ng/ml) from each patient. The areas under the concentration-versus-time curves (AUCs) were similar (P = 0.85) for the 1.5- and 3.0-mg/kg doses, while the apparent oral clearance (CL/F) was significantly higher (P = 0.05) for the 3-mg/kg dose. Pharmacokinetic parameters differed by patient age. In comparing those children older and younger than the median age of 5.1 years, AUC (P = 0.03), maximum concentration of drug in serum (P = 0.004), and the concentration at 8 h postdosing (P = 0.02) were significantly lower for the younger children. There were no significant differences for apparent volume of distribution and CL/F normalized to body surface area, but there was a suggestive difference in half-life (P = 0.07) among the subjects in the older and younger age groups. No significant adverse events were encountered. These data provide the basis for a multidose phase II study of adefovir dipivoxil in HIV-infected infants and children.
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Affiliation(s)
- W T Hughes
- St. Jude Children's Research Hospital, Memphis, TN 38105-2794, USA.
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Martin LT, Cretton-Scott E, Placidi L, Faraj A, Loi AG, Schinazi RF, McClure HM, Gosselin G, Imbach JL, Sommadossi JP. In vitro and in vivo metabolism and pharmacokinetics of bis [(t-butyl)-S-acyl-2-thioethyl]-beta-L-2',3'-dideoxy-5-fluorocytidine monophosphate. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2000; 19:481-99. [PMID: 10772729 DOI: 10.1080/15257770008033023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Exposure to 10 &M L-FddCMP-bisSATE led to formation of intracellular L-FddCTP levels of 410.1(+/-) +/- 46.2 and 242.1 +/- 13.2 pmol/10(6) cells in unstimulated and PHAstimulated PBM cells, respectively; whereas, exposure of cells to the parent nucleoside, L-FddC, generated 5-10-fold less L-FddCTP. In Hep-G2 cells and EGF/HGF stimulated and unstimulated primary cultured hepatocytes, the active metabolite reached 113 +/- 29, 23.9 +/- 15.6, and 20.6 +/- 10.5 pmol/10(6) cells. Three other metabolites, L-FddCMP-monoSATE, L-FddCMP-SH, and M I, were detected intracellularly and extracellularly in all cell types examined. Intravenous administered dose of 3 mg/kg L-FddCMP-bisSATE to rhesus monkeys resulted in plasma concentration levels of 2.06 +/- 1.00 and 0.39 +/- 0.15 &M of L-FddCMP-monoSATE and L-FddC, respectively, while the prodrug was completely cleared metabolically within 15 min. Following oral administration of an equivalent dose, the absolute oral bioavailability of L-FddC derived from L-FddCMP-bisSATE administration was 65%.
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Affiliation(s)
- L T Martin
- Department of Clinical Pharmacology, University of Alabama at Birmingham, USA
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Development and optimization of anti-HIV nucleoside analogs and prodrugs: A review of their cellular pharmacology, structure-activity relationships and pharmacokinetics. Adv Drug Deliv Rev 1999; 39:117-151. [PMID: 10837771 DOI: 10.1016/s0169-409x(99)00023-x] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Significant improvements in antiviral therapy have been realized over the past 10 years. Numerous nucleoside analogs, as well as prodrugs of active compounds, have been synthesized and tested for anti-HIV activity. In addition to the five nucleoside analogs currently used clinically for the treatment of HIV infection, a broad spectrum of anti-HIV nucleoside analogs (including 2',3'-dideoxynucleoside analogs, oxathiolanyl 2',3'-dideoxynucleoside analogs, dioxolanyl 2',3'-dideoxynucleoside analogs, carbocyclic 2',3'-dideoxynucleoside analogs and acyclic nucleoside analogs) and their prodrugs (including ester prodrugs, phospholipid prodrugs, dihydropyridine prodrugs, pronucleotides and dinucleotide analogs), targeted at HIV reverse transcriptase, are reviewed with focus on structure-activity relationships, cellular pharmacology and pharmacokinetics. Several of these anti-viral agents show promise in the treatment of AIDS.
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Abstract
Adefovir dipivoxil is an ester prodrug of the nucleoside reverse transcriptase inhibitor adefovir (PMEA), the prototype compound of the acyclic nucleoside phosphonates. It has better oral bioavailability than the parent compound. Adefovir dipivoxil 120mg once daily significantly reduced viral load compared with placebo when added to standard antiretroviral therapy in a 6-month, double-blind study in patients with HIV infection. Viral suppression was maintained during an additional 6-month nonblind extension phase. The drug was most effective in patients with baseline isolates containing the M184V lamivudine resistance mutation according to data from a virological substudy of a large placebo-controlled trial. Adefovir dipivoxil 60mg was as effective as 120mg (both once daily) after 20 weeks' treatment in a randomised double-blind study in antiretroviral-experienced (protease inhibitor-naive) patients. Viral suppression was generally maintained in patients who developed new reverse transcriptase mutations during adefovir dipivoxil monotherapy or combination therapy for up to 12 months. No clear pattern of particular clinical resistance mutations has emerged. GI disturbances, hepatic effects and delayed renal abnormalities are the principal adverse events seen with adefovir dipivoxil. Reductions in serum free carnitine levels may occur and coadministration of L-carnitine is recommended.
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Affiliation(s)
- S Noble
- Adis International Limited, Mairangi Bay, Auckland, New Zealand.
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43
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Zídek Z, Franková D, Holý A. Chemokines, nitric oxide and antiarthritic effects of 9-(2-phosphonomethoxyethyl)adenine (Adefovir). Eur J Pharmacol 1999; 376:91-100. [PMID: 10440094 DOI: 10.1016/s0014-2999(99)00343-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Antiarthritic effects of two acyclic nucleoside phosphonates, 9-(2-phosphonomethoxyethyl)adenine (PMEA; Adefovir) and 9-(2-phosphonomethoxypropyl)adenine (PMPA), as well as their more bioavailable prodrugs, bis(pivaloyloxymethyl)ester of PMEA [bis(POM)-PMEA; Adefovir Dipivoxil] and bis(isopropyloxycarbonyloxymethyl)ester of PMPA [bis(POC)-PMPA], were investigated in a model of adjuvant-induced arthritis in Lewis rats. The drugs were injected subcutaneously at doses of 5-50 mg/kg. PMEA and its prodrug inhibited by > 80% arthritic paw swelling, splenomegaly and fibroadhesive perisplenitis. Both prophylactic and therapeutic dosing regimens were effective. Neither PMPA nor bis(POC)-PMPA suppressed development of arthritic lesions. Substantially reduced nitrite + nitrate levels were detected in serum and urine of PMEA-treated animals as compared to those of untreated diseased controls. Also, complete suppression of the disease-associated, greatly enhanced systemic levels of the chemokine, RANTES (regulated upon activation, normal T cell expressed and secreted), was observed in rats injected with PMEA. Additional in vitro studies showed that PMEA does not change, PMPA enhances, and both prodrugs inhibit the immune-activated NO production. Under the same conditions PMEA inhibits, while PMPA slightly stimulates, secretion of RANTES. Collectively, these data suggest that the in vivo-inhibited production of nitric oxide (NO) is a consequence rather than a mechanism of antiarthritic action of PMEA. Possible mechanisms for the anti-RANTES activity of PMEA remains to be firmly established.
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Affiliation(s)
- Z Zídek
- Institute of Pharmacology, Academy of Sciences of the Czech Republic, Prague.
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44
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Dang Q, Brown BS, van Poelje PD, Colby TJ, Erion MD. Synthesis of phosphonate 3-phthalidyl esters as prodrugs for potential intracellular delivery of phosphonates. Bioorg Med Chem Lett 1999; 9:1505-10. [PMID: 10386925 DOI: 10.1016/s0960-894x(99)00239-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A new prodrug approach for intracellular delivery of phosphonates was developed via the synthesis of 3-phthalidyl esters of 1-naphthalenemethylphosphonate. This approach is advantageous over the traditional acyloxymethyl phosphonate prodrugs, because these prodrugs do not generate formaldehyde and have improved plasma half-lives.
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Affiliation(s)
- Q Dang
- Department of Medicinal Chemistry, Metabasis Therapeutics, Inc., San Diego, CA 92121, USA
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Smeijsters LJ, Franssen FF, Naesens L, de Vries E, Holý A, Balzarini J, de Clercq E, Overdulve JP. Inhibition of the in vitro growth of Plasmodium falciparum by acyclic nucleoside phosphonates. Int J Antimicrob Agents 1999; 12:53-61. [PMID: 10389648 DOI: 10.1016/s0924-8579(99)00003-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Forty-eight acyclic nucleoside phosphonates (putative prodrugs of acyclic nucleoside triphosphate inhibitors of DNA replication) have been evaluated for in vitro antiplasmodial activity. Only certain purine derivatives with a hydroxyl group attached to the acyclic sugar moiety displayed antiplasmodial activity. The two most active analogs were (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine ((S)-HPMPA, IC50=0.18+/-0.07 microM) and (S)-3-deaza-HPMPA (IC50=0.29+/-0.08 microM). Their cyclic derivatives, containing an ester bond between the phosphonate and the hydroxyl group, were slightly less active. All tested compounds that lacked the hydroxyl group, including potent antiretrovirus analogs such as 9-(2-phosphonylmethoxyethyl)adenine (PMEA) and the (S)-HPMPA derivatives (R)-PMPA and (S)-FPMPA, did not show any activity, even at very high concentrations ( >250 microM). Similarly, pyrimidine analogs of (S)-HPMPA, such as (S)-HPMPT, (S)-HPMPU and the anti-herpesvirus analog (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl) cytosine ((S)-HPMPC), were devoid of any antiplasmodial activity. In addition, 11 acyclic nucleoside (non-phosphorylated) analogs--which in contrast to the acyclic nucleoside phosphonates require the presence of a monophosphorylating enzyme for the first activation step--were tested. None of them inhibited the growth of the parasite. In short three chemical entities seem to be imperative for antiplasmodial activity: a purine base, a hydroxyl group in the acyclic side chain and a phosphonate group terminating this chain.
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Affiliation(s)
- L J Smeijsters
- Institute of Infectious Diseases and Immunology, Department of Parasitology and Tropical Veterinary Medicine, Faculty of Veterinary Medicine, University of Utrecht, The Netherlands
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Yu RH, Schultze LM, Rohloff JC, Dudzinski PW, Kelly DE. Process Optimization in the Synthesis of 9-[2-(Diethylphosphonomethoxy)ethyl]adenine: Replacement of Sodium Hydride with Sodium tert-Butoxide as the Base for Oxygen Alkylation. Org Process Res Dev 1998. [DOI: 10.1021/op980067v] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Richard H. Yu
- Process Research, Gilead Sciences, Inc., 353 Lakeside Drive, Foster City, California 94404, and Process Chemistry, Raylo Chemicals, Inc., 8045 Argyll Road, Edmonton, Alberta, Canada T6C4A9
| | - Lisa M. Schultze
- Process Research, Gilead Sciences, Inc., 353 Lakeside Drive, Foster City, California 94404, and Process Chemistry, Raylo Chemicals, Inc., 8045 Argyll Road, Edmonton, Alberta, Canada T6C4A9
| | - John C. Rohloff
- Process Research, Gilead Sciences, Inc., 353 Lakeside Drive, Foster City, California 94404, and Process Chemistry, Raylo Chemicals, Inc., 8045 Argyll Road, Edmonton, Alberta, Canada T6C4A9
| | - Pawel W. Dudzinski
- Process Research, Gilead Sciences, Inc., 353 Lakeside Drive, Foster City, California 94404, and Process Chemistry, Raylo Chemicals, Inc., 8045 Argyll Road, Edmonton, Alberta, Canada T6C4A9
| | - Daphne E. Kelly
- Process Research, Gilead Sciences, Inc., 353 Lakeside Drive, Foster City, California 94404, and Process Chemistry, Raylo Chemicals, Inc., 8045 Argyll Road, Edmonton, Alberta, Canada T6C4A9
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De Valette F, Barascut JL, Imbach JL. Synthesis and Antiviral Evaluation of 2′-Deoxy-4′-thio-L-nucleosides and Their Phosphotriester Derivatives BearingS-Acyl-2-thioethyl Bioreversible Phosphate-Protecting Groups. ACTA ACUST UNITED AC 1998. [DOI: 10.1080/07328319808004318] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Nicoll AJ, Colledge DL, Toole JJ, Angus PW, Smallwood RA, Locarnini SA. Inhibition of duck hepatitis B virus replication by 9-(2-phosphonylmethoxyethyl)adenine, an acyclic phosphonate nucleoside analogue. Antimicrob Agents Chemother 1998; 42:3130-5. [PMID: 9835503 PMCID: PMC106011 DOI: 10.1128/aac.42.12.3130] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/1998] [Accepted: 08/29/1998] [Indexed: 11/20/2022] Open
Abstract
The use of regimens that use nucleoside analogues for the treatment of chronic hepatitis B virus infection is often limited because of their high relapse rates. This is thought to be due to the persistence of virus in nonhepatocyte reservoirs and/or the viral covalently closed circular (CCC) DNA species in the nucleus of infected hepatocytes. We have evaluated the novel nucleoside analogue 9-(2-phosphonylmethoxyethyl)adenine (PMEA) in the duck model of hepatitis B. Eight Pekin-Aylesbury ducks congenitally infected with the duck hepatitis B virus (DHBV) were treated with PMEA at a dosage of 15 mg/kg of body weight/day via the intraperitoneal route for 4 weeks. At the end of the treatment period, four animals were killed and the remainder were monitored for a further 4-week drug-free period before analysis. The results were compared with those for eight age-matched, untreated controls. The levels of viremia, the total intrahepatic DHBV load, and CCC DNA, viral RNA, and protein levels were measured by Southern hybridization, Northern hybridization, and immunoblotting of the appropriate specimen, respectively. Viral proteins and DNA were also measured by immunohistochemistry (IHC) and in situ hybridization (ISH) of sections of liver and pancreatic tissue. PMEA treatment reduced the viremia to undetectable levels, while the total viral DNA load in the liver was reduced by 95% compared to the control level. Viral RNA and protein levels decreased by approximately 30%. ISH and IHC confirmed the PMEA-related intrahepatic changes and established that the amount of virus in bile duct epithelial cells (BDEC) was reduced by 70% during therapy. During the follow-up period all parameters of active virological replication returned to those for the age-matched controls. PMEA had no significant effect upon the number of virus-infected islet or acinar cells in the pancreas. PMEA at a dosage of 15 mg/kg/day has potent activity against DHBV found within hepatocytes and BDEC and inhibits DHBV replication in BDEC.
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Affiliation(s)
- A J Nicoll
- Victorian Infectious Diseases Reference Laboratory, North Melbourne, Victoria 3051, Australia
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Srinivas RV, Middlemas D, Flynn P, Fridland A. Human immunodeficiency virus protease inhibitors serve as substrates for multidrug transporter proteins MDR1 and MRP1 but retain antiviral efficacy in cell lines expressing these transporters. Antimicrob Agents Chemother 1998; 42:3157-62. [PMID: 9835508 PMCID: PMC106016 DOI: 10.1128/aac.42.12.3157] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/1998] [Accepted: 10/03/1998] [Indexed: 11/20/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs)-saquinavir, ritonavir, nelfinavir, and indinavir-interact with the ABC-type multidrug transporter proteins MDR1 and MRP1 in CEM T-lymphocytic cell lines. Calcein fluorescence was significantly enhanced in MDR1(+) CEM/VBL100 and MRP1(+) CEM/VM-1-5 cells incubated in the presence of various HIV PIs and calcein acetoxymethyl ester. HIV PIs also enhanced the cytotoxic activity of doxorubicin, a known substrate for MDR1 and MRP1, in both VBL100 and VM-1-5 CEM lines. Saquinavir, ritonavir, and nelfinavir enhanced doxorubicin toxicity in CEM/VBL100 cells by approximately three- to sevenfold. Saquinavir and ritonavir also enhanced doxorubicin toxicity in CEM/VM-1-5 cells. HIV-1 replication was effectively inhibited by the various PIs in all of the cell lines, and the 90% inhibitory concentration for a given compound was comparable between the different cell types. Therefore, overexpression of MDR1 or MRP1 by T lymphocytes is not likely to limit the antiviral efficacy of HIV PI therapy.
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Affiliation(s)
- R V Srinivas
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
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Hatse S, De Clercq E, Balzarini J. Enhanced 9-(2-phosphonylmethoxyethyl)adenine secretion by a specific, indomethacin-sensitive efflux pump in a mutant 9-(2-phosphonylmethoxyethyl)adenine-resistant human erythroleukemia K562 cell line. Mol Pharmacol 1998; 54:907-17. [PMID: 9804626 DOI: 10.1124/mol.54.5.907] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have investigated the molecular basis of the 100-fold resistance of mutant human erythroleukemia K562/PMEA-1 cells to the antiproliferative potential of 9-(2-phosphonylmethoxyethyl)adenine (PMEA). Upon exposure to high PMEA concentrations, comparable intracellular PMEA levels were initially observed in mutant K562/PMEA-1 and wild-type K562/0 cells, indicating that PMEA influx was unaltered. However, after 4 hr of exposure to 0.2 microM [3H]bis(pivaloyloxymethyl)-PMEA [bis(POM)-PMEA], the total intracellular level of unphosphorylated and mono- and diphosphorylated PMEA was 2.8-fold lower in K562/PMEA-1 than in K562/0 cells. Increased PMEA secretion from K562/PMEA-1 cells (compared with K562/0 cells) became more pronounced upon prolonged exposure to bis(POM)-PMEA; after 24 hr, K562/PMEA-1 cells showed 65-fold lower total intracellular PMEA levels than K562/0 cells and at 48 hr, >400-fold less total PMEA was detected in K562/PMEA-1 cells. In addition, PMEA phosphorylation was 25- to 50-fold less efficient in K562/PMEA-1 than in K562/0 cells, pointing to an additional defect at the level of the metabolism of PMEA. The PMEA efflux mechanism was shown to be temperature- and azide-dependent, was markedly inhibited by indomethacin, and did not recognize adenine nucleotides or the phosphorylated metabolites of 3'-azido-3'-deoxythymidine. Also, over a 28-hr period, PMEA efflux was not affected by an inhibitor of RNA synthesis (actinomycin D) or protein synthesis (cycloheximide). Our studies revealed that resistance of K562/PMEA-1 cells to PMEA is the combined result of a severely impaired PMEA phosphorylation on the one hand, and an enhanced PMEA secretion by a highly specific, indomethacin-sensitive efflux pump, different from the classical P-glycoprotein- and multidrug resistance protein-mediated resistance mechanisms, on the other hand.
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Affiliation(s)
- S Hatse
- Laboratory of Virology and Experimental Chemotherapy, Rega Institute for Medical Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
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