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Development of a TLR7/8 agonist adjuvant formulation to overcome early life hyporesponsiveness to DTaP vaccination. Sci Rep 2022; 12:16860. [PMID: 36258023 PMCID: PMC9579132 DOI: 10.1038/s41598-022-20346-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 09/12/2022] [Indexed: 12/02/2022] Open
Abstract
Infection is the most common cause of mortality early in life, yet the broad potential of immunization is not fully realized in this vulnerable population. Most vaccines are administered during infancy and childhood, but in some cases the full benefit of vaccination is not realized in-part. New adjuvants are cardinal to further optimize current immunization approaches for early life. However, only a few classes of adjuvants are presently incorporated in vaccines approved for human use. Recent advances in the discovery and delivery of Toll-like receptor (TLR) agonist adjuvants have provided a new toolbox for vaccinologists. Prominent among these candidate adjuvants are synthetic small molecule TLR7/8 agonists. The development of an effective infant Bordetella pertussis vaccine is urgently required because of the resurgence of pertussis in many countries, contemporaneous to the switch from whole cell to acellular vaccines. In this context, TLR7/8 adjuvant based vaccine formulation strategies may be a promising tool to enhance and accelerate early life immunity by acellular B. pertussis vaccines. In the present study, we optimized (a) the formulation delivery system, (b) structure, and (c) immunologic activity of novel small molecule imidazoquinoline TLR7/8 adjuvants towards human infant leukocytes, including dendritic cells. Upon immunization of neonatal mice, this TLR7/8 adjuvant overcame neonatal hyporesponsiveness to acellular pertussis vaccination by driving a T helper (Th)1/Th17 biased T cell- and IgG2c-skewed humoral response to a licensed acellular vaccine (DTaP). This potent immunization strategy may represent a new paradigm for effective immunization against pertussis and other pathogens in early life.
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Talukdar A, Ganguly D, Roy S, Das N, Sarkar D. Structural Evolution and Translational Potential for Agonists and Antagonists of Endosomal Toll-like Receptors. J Med Chem 2021; 64:8010-8041. [PMID: 34107682 DOI: 10.1021/acs.jmedchem.1c00300] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Toll-like receptors (TLRs) are members of a large family of evolutionarily conserved pattern recognition receptors (PRRs), which serve as key components of the innate immune system by playing a pivotal role in sensing "nonself" ligands. Endosomal TLRs (TLR3, TLR7, TLR8, and TLR9) can recognize pathogen-derived nucleic acid and initiate an innate immune response because they react against both self- and non-self-origin nucleic acid molecules. Accordingly, both receptor agonists and antagonists are potentially useful in disparate clinical contexts and thus are globally sought after. Recent research has revealed that agonists and antagonists share an overlapping binding region. This Perspective highlights rational medicinal chemistry approaches to elucidate the structural attributes of small molecules capable of agonism or antagonism or of elegantly switching between the two. The structural evolution of different chemotypes can provide the framework for the future development of endosomal TLR agonists and antagonists.
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Affiliation(s)
- Arindam Talukdar
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India.,Academy of Scientific and Innovative Research, Ghaziabad 201002, Uttar Pradesh, India
| | - Dipyaman Ganguly
- IICB-Translational Research Unit of Excellence, Department of Cancer Biology and Inflammatory Disorders, CSIR-Indian Institute of Chemical Biology, CN6, Sector V, Salt Lake, Kolkata 700091, West Bengal, India.,Academy of Scientific and Innovative Research, Ghaziabad 201002, Uttar Pradesh, India
| | - Swarnali Roy
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India
| | - Nirmal Das
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India.,Academy of Scientific and Innovative Research, Ghaziabad 201002, Uttar Pradesh, India
| | - Dipika Sarkar
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India
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Smith AJ, Li Y, Bazin HG, St-Jean JR, Larocque D, Evans JT, Baldridge JR. Evaluation of novel synthetic TLR7/8 agonists as vaccine adjuvants. Vaccine 2016; 34:4304-12. [PMID: 27402566 PMCID: PMC4968040 DOI: 10.1016/j.vaccine.2016.06.080] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 06/27/2016] [Accepted: 06/29/2016] [Indexed: 12/21/2022]
Abstract
Small-molecule adjuvants that boost and direct adaptive immunity provide a powerful means to increase the effectiveness of vaccines. Through rational design several novel imidazoquinoline and oxoadenine TLR7/8 agonists, each with unique molecular modifications, were synthesized and assessed for their ability to augment adaptive immunity. All agonists bound human TLR7 and TLR8 and induced maturation of both human mDCs and pDCs. All agonists prompted production of type I interferon and/or proinflammatory cytokines, albeit with varying potencies. In most in vitro assays, the oxoadenine class of agonists proved more potent than the imidazoquinolines. Therefore, an optimized oxoadenine TLR7/8 agonist that demonstrated maximal activity in the in vitro assays was further assessed in a vaccine study with the CRM197 antigen in a porcine model. Antigen-specific antibody production was greatly enhanced in a dose dependent manner, with antibody titers increased 800-fold compared to titers from pigs vaccinated with the non-adjuvanted vaccine. Moreover, pigs vaccinated with antigen containing the highest dose of adjuvant promoted a 13-fold increase in the percentage of antigen-specific CD3(+)/CD8(+) T cells over pigs vaccinated with antigen alone. Together this work demonstrates the promise of these novel TLR7/8 agonists as effective human vaccine adjuvants.
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Affiliation(s)
| | - Yufeng Li
- GSK Vaccines, Hamilton, MT 59840, USA
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Mwakwari SC, Bess LS, Bazin HG, Johnson DA. Efficient tin-mediated synthesis of lysophospholipid conjugates of a TLR7/8-active imidazoquinoline. Tetrahedron Lett 2016; 57:2093-2096. [PMID: 32863447 PMCID: PMC7451898 DOI: 10.1016/j.tetlet.2016.03.110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The chemical synthesis of lysophospholipids often involves multiple synthetic and chromatographic steps due to the incorporation of the fatty acyl group onto the glycerol scaffold early in the synthesis. We report herein a new protocol for the lysophosphatidylation of alcohols and its application to the synthesis of lysophospholipid conjugates of TLR7/8-active imidazoquinoline 3. This new procedure, which is based on the tin-mediated regioselective acylation of late-stage phosphoglycerol intermediate 17, overcomes many of the drawbacks of conventional lysophosphatidylation methods and allows introduction of different fatty acyl groups in the penultimate step.
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Bazin HG, Bess LS, Livesay MT, Mwakwari SC, Johnson DA. Phospholipidation of TLR7/8-active imidazoquinolines using a tandem phosphoramidite method. Tetrahedron Lett 2016; 57:2063-2066. [PMID: 32863446 PMCID: PMC7451945 DOI: 10.1016/j.tetlet.2016.03.091] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A high-yielding and scalable phosphoramidite procedure was developed for the phospholipidation of TLR7/8-active imidazoquinolines. This method involves the reaction of a 1,2-diacyl- or dialkyl-sn-glycerol or 3-chlolesterylalkanol with 2-cyanoethyl N,N,N',N'-tetraisopropylphosphordiamidite in the presence of 1H-tetrazole followed by treatment of the resulting N,N'-diisopropylphosphoramidite lipid in situ with 1-imidazoquinolinylalkanols. The resulting phosphite can be purified or directly oxidized with t-butyl hydroperoxide. The cyanoethyl protecting group is then removed with triethylamine and the phospholipidated imidazoquinoline products isolated in good yield and purity by simple filtration.
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Gao D, Diao Y, Li W, Gao N, Liu Y, Wang Z, Jiang W, Jin G. Toll-like receptor 7 inactive ligands enhanced cytokine induction by conjugation to weak antigens. ChemMedChem 2015; 10:977-80. [PMID: 25882779 DOI: 10.1002/cmdc.201500088] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 03/25/2015] [Indexed: 11/09/2022]
Abstract
Toll-like receptors (TLRs) 7/8 are key targets in the design and development of small-molecule drugs serving as anticancer/antiviral agents and vaccine adjuvants. Clinical trials of imiquimod were discontinued owing to its serious adverse side effects. Herein we report the synthesis and biological evaluation of a series of 8-hydroxy-2-(2-methoxyethoxy)adenine derivatives that cannot induce cytokine production and that lack activity toward TLR 7/8. Their ability to triggering remarkable levels of cytokine production were revealed upon their conjugation with antigens that have weak immunogenicity. This discovery demonstrated that TLR 7 can be activated by coupling an antigen to the terminal carboxyl group at N9 of the inactive ligand adenine analogues. These inactive analogues may be well suited as new adjuvants with superior activity after conjugation, effectively decreasing the side effects caused by conventional adjuvants.
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Affiliation(s)
- Dong Gao
- Cancer Research Center, Shenzhen University, Shenzhen 518060 (P. R. China). .,Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Shenzhen University, Shenzhen 518060 (P. R. China).
| | - Yuwen Diao
- Cancer Research Center, Shenzhen University, Shenzhen 518060 (P. R. China)
| | - Wang Li
- Cancer Research Center, Shenzhen University, Shenzhen 518060 (P. R. China)
| | - Ningning Gao
- Cancer Research Center, Shenzhen University, Shenzhen 518060 (P. R. China)
| | - Yu Liu
- Cancer Research Center, Shenzhen University, Shenzhen 518060 (P. R. China).,Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Shenzhen University, Shenzhen 518060 (P. R. China)
| | - Zhulin Wang
- Cancer Research Center, Shenzhen University, Shenzhen 518060 (P. R. China)
| | - Wenqi Jiang
- Cancer Research Center, Shenzhen University, Shenzhen 518060 (P. R. China)
| | - Guangyi Jin
- Cancer Research Center, Shenzhen University, Shenzhen 518060 (P. R. China).
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Toll-like receptor 7 agonist therapy with imidazoquinoline enhances cancer cell death and increases lymphocytic infiltration and proinflammatory cytokine production in established tumors of a renal cell carcinoma mouse model. JOURNAL OF ONCOLOGY 2012; 2012:103298. [PMID: 22481916 PMCID: PMC3317372 DOI: 10.1155/2012/103298] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Accepted: 11/14/2011] [Indexed: 12/16/2022]
Abstract
Imidazoquinolines are synthetic toll-like receptor 7 and 8 agonists and potent dendritic cell activators with established anticancer activity. Here we test the hypothesis that imidazoquinoline has in vivo efficacy within established renal cell carcinoma (RCC) tumors. Immunocompetent mice bearing syngeneic RCC xenografts were treated with imidazoquinoline or placebo at two separate time points. Harvested tumors were assayed by TUNEL/caspase-3/Ki67 immunostains to evaluate cell death/apoptosis/proliferation, and CD3/B220/CD45 immunostains to evaluate T-cell lymphocyte/B-cell lymphocyte/pan-leukocyte tumor infiltration. ELISA measurement of tumor and serum levels of proinflammatory cytokines, IL-6 and MCP-1, was performed. A single imidazoquinoline dose significantly decreased RCC tumor growth by 50% and repeat dosing compounded the effect, without observed weight loss or other toxicity. Tumor immunostaining revealed significant increases in cell death and apoptosis without changes in cell proliferation, supporting induction of apoptosis as the primary mechanism of tumor growth suppression. Imidazoquinoline treatment also significantly enhanced peritumoral aggregation and intratumoral infiltration by T-cell lymphocytes, while increasing intratumoral (but not serum) levels of proinflammatory cytokines. In conclusion, imidazoquinoline treatment enhances T-cell lymphocyte infiltration and proinflammatory cytokine production within established mouse RCC tumors, while suppressing tumor growth via induction of cancer cell apoptosis. These findings support a therapeutic role for imidazoquinoline in RCC.
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Horscroft NJ, Pryde DC, Bright H. Antiviral applications of Toll-like receptor agonists. J Antimicrob Chemother 2012; 67:789-801. [PMID: 22258929 DOI: 10.1093/jac/dkr588] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In the past, antiviral research has focused mainly on viral targets. As the search for effective and differentiated antiviral therapies continues, cellular targets are becoming more common, bringing with them a variety of challenges and concerns. Toll-like receptors (TLRs) provide a unique mechanism to induce an antiviral state in the host. In this review we introduce TLRs as targets for the pharmaceutical industry, including how they signal and thereby induce an antiviral state through the production of type I interferons. We examine how TLRs are being therapeutically targeted and discuss several clinically precedented agents for which efficacy and safety data are available. We describe some of the chemistries that have been applied to both small molecule and large molecule leads to tune agonist potency, and offer a differentiated safety profile through targeting certain compartments such as the gut or the lung, thereby limiting systemic drug exposure and affecting systemic cytokine levels. The application of low-dose agonists of TLRs as vaccine adjuvants or immunoprotective agents is also presented. Some of the challenges presented by this approach are then discussed, including viral evasion strategies and mechanism-linked inflammatory cytokine induction.
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Pryde DC, Tran TD, Jones P, Parsons GC, Bish G, Adam FM, Smith MC, Middleton DS, Smith NN, Calo F, Hay D, Paradowski M, Proctor KJW, Parkinson T, Laxton C, Fox DNA, Horscroft NJ, Ciaramella G, Jones HM, Duckworth J, Benson N, Harrison A, Webster R. The discovery of a novel prototype small molecule TLR7 agonist for the treatment of hepatitis C virus infection. MEDCHEMCOMM 2011. [DOI: 10.1039/c0md00197j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Musmuca I, Simeoni S, Caroli A, Ragno R. Small-Molecule Interferon Inducers. Toward the Comprehension of the Molecular Determinants through Ligand-Based Approaches. J Chem Inf Model 2009; 49:1777-86. [DOI: 10.1021/ci900065a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Ira Musmuca
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le A. Moro 5, 00185, Rome, Italy
| | - Silvia Simeoni
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le A. Moro 5, 00185, Rome, Italy
| | - Antonia Caroli
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le A. Moro 5, 00185, Rome, Italy
| | - Rino Ragno
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le A. Moro 5, 00185, Rome, Italy
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Weterings JJ, Khan S, van der Heden van Noort GJ, Melief CJ, Overkleeft HS, van der Burg SH, Ossendorp F, van der Marel GA, Filippov DV. 2-Azidoalkoxy-7-hydro-8-oxoadenine derivatives as TLR7 agonists inducing dendritic cell maturation. Bioorg Med Chem Lett 2009; 19:2249-51. [DOI: 10.1016/j.bmcl.2009.02.095] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 02/23/2009] [Accepted: 02/24/2009] [Indexed: 01/24/2023]
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Isobe Y, Kurimoto A, Tobe M, Hashimoto K, Nakamura T, Norimura K, Ogita H, Takaku H. Synthesis and Biological Evaluation of Novel 9-Substituted-8-Hydroxyadenine Derivatives as Potent Interferon Inducers. J Med Chem 2006; 49:2088-95. [PMID: 16539397 DOI: 10.1021/jm051089s] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Recently we reported the adenine derivatives 3a-d as novel interferon (IFN) inducers. In the present study, we conducted a detailed structure-activity relationship study of analogues of 3a-d with respect to their IFN-inducing activity, mainly focusing on the N(9)-position of the adenine. From this study, we found that introduction of the 3-pyridylmethyl moiety was effective to increase in vitro activity, and compound 9ae was identified as being the most potent IFN inducer. This compound gave a minimum effective concentration (MEC) of 3 nM, which is comparable with that of R-848, a second generation IFN inducer. Compound 9ae also demonstrated potent IFN-inducing activity at a dose of 0.1 mg/kg by oral administration in mice. Furthermore, compound 9ae induced IFN in monkeys in a dose dependent manner, with a potency superior to that of R-848. In addition, 9ae did not cause emesis in ferrets even at a dose of 30 mg/kg. In this study the maximum plasma concentration of 9ae was 1019 ng/mL (ca. 3.1 microM), which was approximately 1000-fold higher than the MEC value. Therefore, with respect to both the efficacy and the safety margin, compound 9ae (SM-276001) is considered to be a promising compound as an orally active IFN inducer.
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Affiliation(s)
- Yoshiaki Isobe
- Chemistry Research Laboratories and Discovery Research Laboratories II, Dainippon Sumitomo Pharmaceuticals Company Ltd., 1-98, Kasugade Naka, 3-chome, Konohana-ku, Osaka 554-0022, Japan.
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Kurimoto A, Ogino T, Ichii S, Isobe Y, Tobe M, Ogita H, Takaku H, Sajiki H, Hirota K, Kawakami H. Synthesis and evaluation of 2-substituted 8-hydroxyadenines as potent interferon inducers with improved oral bioavailabilities. Bioorg Med Chem 2004; 12:1091-9. [PMID: 14980621 DOI: 10.1016/j.bmc.2003.12.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2003] [Accepted: 12/05/2003] [Indexed: 11/28/2022]
Abstract
In order to create novel compounds which possess potent interferon (IFN) inducing activities with excellent oral bioavailabilities, a series of 8-hydroxyadenines, which have various alkoxy or alkylthio moieties at the adenine C(2)-position, were synthesized and evaluated. The introduction of hydrophobic groups was not considered to be effective for potentiating the IFN-inducing activity, but several compounds having hydrophilic groups were effective. Among the compounds tested, compound 13f induced IFN from the dosage of 0.03 mg/kg, which was approximately 100-fold more potent than that of Imiquimod, and showed an excellent oral bioavailability (F=40%) which was 10-fold improved over 5, a lead compound (F=4%).
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Affiliation(s)
- Ayumu Kurimoto
- Research Division, Discovery Research Laboratories II, Sumitomo Pharmaceuticals Co. Ltd., Konohana-ku, Osaka 554-0022, Japan.
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Pawlotsky JM, McHutchison JG. Hepatitis C. Development of new drugs and clinical trials: promises and pitfalls. Summary of an AASLD hepatitis single topic conference, Chicago, IL, February 27-March 1, 2003. Hepatology 2004; 39:554-67. [PMID: 14768012 DOI: 10.1002/hep.20065] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Jean-Michel Pawlotsky
- Department of Virology (EA 3489), Henri Mondor Hospital, University of Paris XII, Créteil, France
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Kurimoto A, Ogino T, Ichii S, Isobe Y, Tobe M, Ogita H, Takaku H, Sajiki H, Hirota K, Kawakami H. Synthesis and structure–Activity relationships of 2-Amino-8-hydroxyadenines as orally active interferon inducing agents. Bioorg Med Chem 2003; 11:5501-8. [PMID: 14642594 DOI: 10.1016/j.bmc.2003.09.032] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recently, we have reported the 8-hydroxyadenine derivatives (2-4) as a novel class of interferon (IFN) inducing agents. In the present study, a series of 8-hydroxyadenines, which possess various amino moieties at the adenine C(2)-position, were synthesized and evaluated for their ability to induce endogenous IFN in comparison to the known active agent, Imiquimod. Among the compounds prepared, compound 9o possessing a 2-methoxyethylamino group at C(2)-position of adenine was found to exhibit potent IFN inducing activity in vivo. Compound 9o induced IFN from the dosage of 0.1 mg/kg, which was 30-fold potent than that of Imiquimod, and showed a good oral bioavailability (F=81%).
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Affiliation(s)
- Ayumu Kurimoto
- Research Division, Discovery Research Laboratories II, Sumitomo Pharmaceuticals Co Ltd, Konohana-ku, Osaka 554-0022, Japan.
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Isobe Y, Tobe M, Ogita H, Kurimoto A, Ogino T, Kawakami H, Takaku H, Sajiki H, Hirota K, Hayashi H. Synthesis and structure-activity relationships of 2-substituted-8-hydroxyadenine derivatives as orally available interferon inducers without emetic side effects. Bioorg Med Chem 2003; 11:3641-7. [PMID: 12901909 DOI: 10.1016/s0968-0896(03)00369-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Recently we reported the adenine derivatives (2-4) as new interferon (IFN) inducers. In the present study, we conducted a detailed structure and activity relationship study of 4 and its related derivatives on IFN inducing activity. From this study, we found that compound 4 exhibited the most potent IFN inducing activity in vitro with a minimum effective concentration of 0.01 microM, and 4 also showed strong IFN-inducing activity at doses of more than 0.3mg/kg by oral administration in mice. This potency was 10-fold stronger than that of Imiquimod. Moreover, 4 did not cause emesis in ferrets even at doses as high as 10mg/kg, whereas, 80% of animals were emetic when orally administered with the same dose of Imiquimod. These results indicate that compound 4 is superior to Imiquimod with respect to efficacy and safety.
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Affiliation(s)
- Yoshiaki Isobe
- Research Division, Discovery Research Laboratories II, Sumitomo Pharmaceuticals Co. Ltd., Konohana-ku, 554-0022, Osaka, Japan
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