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Pandya AK, Patravale VB. Computational avenues in oral protein and peptide therapeutics. Drug Discov Today 2021; 26:1510-1520. [PMID: 33684525 DOI: 10.1016/j.drudis.2021.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/12/2020] [Accepted: 03/02/2021] [Indexed: 12/19/2022]
Abstract
Proteins and peptides are amongst the most sought-after biomolecules because of their exceptional potential to cater to a vast range of diseases. Although widely studied and researched, the oral delivery of these biomolecules remains a challenge. Alongside formulation strategies, approaches to overcome the inherent barriers for peptide absorption are being designed at the molecular level to establish a sound rationale and to achieve higher bioavailability. Computer-aided drug design (CADD) is a modern in silico approach for developing successful bio-formulations. CADD enables intricate study of the biomolecules in conjunction with their target sites or receptors at the molecular level. Knowledge of the molecular interactions of proteins and peptides makes way for the pre-screening of suitable formulation components and facilitates their delivery.
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Affiliation(s)
- Anjali K Pandya
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Matunga, Mumbai, 400019, India
| | - Vandana B Patravale
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Matunga, Mumbai, 400019, India.
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2
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Song H, Allison SJ, Brabec V, Bridgewater HE, Kasparkova J, Kostrhunova H, Novohradsky V, Phillips RM, Pracharova J, Rogers NJ, Shepherd SL, Scott P. Glycoconjugated Metallohelices have Improved Nuclear Delivery and Suppress Tumour Growth In Vivo. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Hualong Song
- Department of Chemistry University of Warwick Coventry CV4 7AL UK
| | - Simon J. Allison
- School of Applied Sciences University of Huddersfield Huddersfield HD1 3DH UK
| | - Viktor Brabec
- The Czech Academy of Sciences Institute of Biophysics Kralovopolska 135 61265 Brno Czech Republic
| | | | - Jana Kasparkova
- The Czech Academy of Sciences Institute of Biophysics Kralovopolska 135 61265 Brno Czech Republic
| | - Hana Kostrhunova
- The Czech Academy of Sciences Institute of Biophysics Kralovopolska 135 61265 Brno Czech Republic
| | - Vojtech Novohradsky
- The Czech Academy of Sciences Institute of Biophysics Kralovopolska 135 61265 Brno Czech Republic
| | - Roger M. Phillips
- School of Applied Sciences University of Huddersfield Huddersfield HD1 3DH UK
| | - Jitka Pracharova
- The Czech Academy of Sciences Institute of Biophysics Kralovopolska 135 61265 Brno Czech Republic
- Department of Biophysics Centre of the Region Hana for Biotechnological and Agricultural Research Faculty of Science Palacký University Šlechtitelů 27 78371 Olomouc Czech Republic
| | - Nicola J. Rogers
- Department of Chemistry University of Warwick Coventry CV4 7AL UK
| | | | - Peter Scott
- Department of Chemistry University of Warwick Coventry CV4 7AL UK
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3
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Song H, Allison SJ, Brabec V, Bridgewater HE, Kasparkova J, Kostrhunova H, Novohradsky V, Phillips RM, Pracharova J, Rogers NJ, Shepherd SL, Scott P. Glycoconjugated Metallohelices have Improved Nuclear Delivery and Suppress Tumour Growth In Vivo. Angew Chem Int Ed Engl 2020; 59:14677-14685. [PMID: 32489012 PMCID: PMC7497174 DOI: 10.1002/anie.202006814] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Indexed: 12/19/2022]
Abstract
Monosaccharides are added to the hydrophilic face of a self-assembled asymmetric FeII metallohelix, using CuAAC chemistry. The sixteen resulting architectures are water-stable and optically pure, and exhibit improved antiproliferative selectivity against colon cancer cells (HCT116 p53+/+ ) with respect to the non-cancerous ARPE-19 cell line. While the most selective compound is a glucose-appended enantiomer, its cellular entry is not mainly glucose transporter-mediated. Glucose conjugation nevertheless increases nuclear delivery ca 2.5-fold, and a non-destructive interaction with DNA is indicated. Addition of the glucose units affects the binding orientation of the metallohelix to naked DNA, but does not substantially alter the overall affinity. In a mouse model, the glucose conjugated compound was far better tolerated, and tumour growth delays for the parent compound (2.6 d) were improved to 4.3 d; performance as good as cisplatin but with the advantage of no weight loss in the subjects.
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Affiliation(s)
- Hualong Song
- Department of ChemistryUniversity of WarwickCoventryCV4 7ALUK
| | - Simon J. Allison
- School of Applied SciencesUniversity of HuddersfieldHuddersfieldHD1 3DHUK
| | - Viktor Brabec
- The Czech Academy of SciencesInstitute of BiophysicsKralovopolska 13561265BrnoCzech Republic
| | | | - Jana Kasparkova
- The Czech Academy of SciencesInstitute of BiophysicsKralovopolska 13561265BrnoCzech Republic
| | - Hana Kostrhunova
- The Czech Academy of SciencesInstitute of BiophysicsKralovopolska 13561265BrnoCzech Republic
| | - Vojtech Novohradsky
- The Czech Academy of SciencesInstitute of BiophysicsKralovopolska 13561265BrnoCzech Republic
| | - Roger M. Phillips
- School of Applied SciencesUniversity of HuddersfieldHuddersfieldHD1 3DHUK
| | - Jitka Pracharova
- The Czech Academy of SciencesInstitute of BiophysicsKralovopolska 13561265BrnoCzech Republic
- Department of BiophysicsCentre of the Region Hana for Biotechnological and Agricultural ResearchFaculty of SciencePalacký UniversityŠlechtitelů 2778371OlomoucCzech Republic
| | | | | | - Peter Scott
- Department of ChemistryUniversity of WarwickCoventryCV4 7ALUK
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4
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Overcoming the intestinal barrier: A look into targeting approaches for improved oral drug delivery systems. J Control Release 2020; 322:486-508. [DOI: 10.1016/j.jconrel.2020.04.006] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 12/17/2022]
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Aljohani S, Hussein WM, Toth I, Simerska P. Carbohydrates in Vaccine Development. Curr Drug Deliv 2020; 16:609-617. [PMID: 31267872 DOI: 10.2174/1567201816666190702153612] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/25/2019] [Accepted: 05/29/2019] [Indexed: 02/03/2023]
Abstract
Despite advances in the development of new vaccines, there are still some diseases with no vaccine solutions. Therefore, further efforts are required to more comprehensively discern the different antigenic components of these microorganisms on a molecular level. This review summarizes advancement in the development of new carbohydrate-based vaccines. Following traditional vaccine counterparts, the carbohydrate-based vaccines introduced a new approach in fighting infectious diseases. Carbohydrates have played various roles in the development of carbohydrate-based vaccines, which are described in this review, including carbohydrates acting as antigens, carriers or targeting moieties. Carbohydrate-based vaccines against infectious diseases, such as group A streptococcus, meningococcal meningitis and human immunodeficiency virus, are also discussed. A number of carbohydrate- based vaccines, such as Pneumovax 23, Menveo and Pentacel, have been successfully marketed in the past few years and there is a promising standpoint for many more to come in the near future.
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Affiliation(s)
- Salwa Aljohani
- The University of Queensland, School of Chemistry and Molecular Biosciences, Cooper Road, St. Lucia QLD 4072, Australia
| | - Waleed M Hussein
- The University of Queensland, School of Chemistry and Molecular Biosciences, Cooper Road, St. Lucia QLD 4072, Australia
| | - Istvan Toth
- The University of Queensland, School of Chemistry and Molecular Biosciences, Cooper Road, St. Lucia QLD 4072, Australia.,The University of Queensland, School of Pharmacy, Pharmacy Australia Centre of Excellence, Cornwall Street, Woolloongabba, QLD 4072, Australia.,Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Pavla Simerska
- The University of Queensland, School of Chemistry and Molecular Biosciences, Cooper Road, St. Lucia QLD 4072, Australia
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Tremblay T, Robert-Scott G, Bérubé C, Carpentier A, Voyer N, Giguère D. Synthesis of C-terminal glycopeptidesviaoxime resin aminolysis. Chem Commun (Camb) 2019; 55:13741-13744. [DOI: 10.1039/c9cc07481c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We developed a general solid-phase approach to complex C-terminal glycopeptides.
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Affiliation(s)
- Thomas Tremblay
- Département de Chimie and PROTEO
- Université Laval
- Faculté des sciences et de génie
- Québec
- Canada
| | - Gabrielle Robert-Scott
- Département de Chimie and PROTEO
- Université Laval
- Faculté des sciences et de génie
- Québec
- Canada
| | - Christopher Bérubé
- Département de Chimie and PROTEO
- Université Laval
- Faculté des sciences et de génie
- Québec
- Canada
| | - Antoine Carpentier
- Département de Chimie and PROTEO
- Université Laval
- Faculté des sciences et de génie
- Québec
- Canada
| | - Normand Voyer
- Département de Chimie and PROTEO
- Université Laval
- Faculté des sciences et de génie
- Québec
- Canada
| | - Denis Giguère
- Département de Chimie and PROTEO
- Université Laval
- Faculté des sciences et de génie
- Québec
- Canada
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7
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Varamini P, Mansfeld FM, Giddam AK, Steyn F, Toth I. New gonadotropin-releasing hormone glycolipids with direct antiproliferative activity and gonadotropin-releasing potency. Int J Pharm 2017; 521:327-336. [PMID: 28232269 DOI: 10.1016/j.ijpharm.2017.02.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 02/10/2017] [Accepted: 02/19/2017] [Indexed: 11/19/2022]
Affiliation(s)
- Pegah Varamini
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia.
| | - Friederike M Mansfeld
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Ashwini Kumar Giddam
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Frederik Steyn
- The University of Queensland Centre for Clinical Research and the School of Biomedical Sciences, Brisbane, Australia
| | - Istvan Toth
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia; School of Pharmacy, The University of Queensland, Brisbane, Australia; Institute for Molecular Biosciences, The University of Queensland, Brisbane, Australia
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8
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Murakami T. A Minireview: Usefulness of Transporter-Targeted Prodrugs in Enhancing Membrane Permeability. J Pharm Sci 2016; 105:2515-2526. [DOI: 10.1016/j.xphs.2016.05.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 04/28/2016] [Accepted: 05/03/2016] [Indexed: 11/26/2022]
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Abstract
Naturally occurring glycopeptides and glycoproteins play important roles in biological processes. Glycosylation is one of the most common post-translational modifications in vivo. Glycopeptides are involved in cell signaling and sorting, providing cell surface markers for recognition. From the drug design and synthesis perspective, modification of a peptide through glycosylation results in increased bioavailability and bioactivity of glycopeptides in living systems with negligible toxicity of degradation products. Glycopeptide synthesis can be accomplished through incorporation of a glycosylated amino acid in solid phase peptide synthesis (SPPS) to form the desired peptide, or via incorporation of sugar-amino acid moieties. Additionally, research indicates that glycosylation increases penetration of the blood-brain barrier (BBB) by peptides, which may lead to novel therapeutics for neurological disorders. Recent applications of glycopeptides have focused on the in vivo central nervous system (CNS) effects after peripheral administration of centrally active peptides modified with various carbohydrates.
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Affiliation(s)
- Evan M Jones
- Robin Polt Lab, Department of Chemistry and Biochemistry, The University of Arizona Tucson, AZ, USA
| | - Robin Polt
- Robin Polt Lab, Department of Chemistry and Biochemistry, The University of Arizona Tucson, AZ, USA
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10
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Simerska P, Ziora ZM, Fagan V, Goodwin D, Edrous F, Toth I. Design, synthesis and characterisation of mannosylated ovalbumin lipid core peptide self-adjuvanting vaccine delivery system. Drug Deliv Transl Res 2015; 4:246-55. [PMID: 25786879 DOI: 10.1007/s13346-013-0173-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Peptide-based vaccine delivery can be hampered by rapid peptidase activity and poor inherent immunogenicity. The self-adjuvanting lipid core peptide system (LCP) has been shown to confer improved stability and immunogenicity on peptide epitopes of group A Streptococcus, Chlamydia, hookworm, and malaria pathogens. However, various diseases, including cancer, still require targeted delivery of their vaccine candidates. For this reason, we have selected two model peptides (ovalbumin CD4(+) and/or CD8(+) T cell epitopes), and incorporated two or four copies of either epitope into our LCP vaccine. Optimised glycosylation of ovalbumin peptides yielded 46 % when microwave-assisted double coupling with 2 eq of carbohydrate derivative, activated by N,N-diisopropylethylamine and (O-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, was performed. All ovalbumin peptides were successfully synthesised and purified in 11-55 % yields by Fmoc- or Boc-chemistry using solid-phase peptide synthesis. The mannosylated ovalbumin peptides were nontoxic to human erythrocytes in haemolytic assay (<2 % haemolysis) and showed increased (up to 20-fold) stability in plasma.
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Affiliation(s)
- Pavla Simerska
- School of Chemistry and Molecular Biosciences, The University of Queensland, Cooper Road, St Lucia, QLD, 4072, Australia,
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11
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Targeting of gastrointestinal tract for amended delivery of protein/peptide therapeutics: Strategies and industrial perspectives. J Control Release 2014; 196:168-83. [DOI: 10.1016/j.jconrel.2014.09.031] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 09/26/2014] [Accepted: 09/30/2014] [Indexed: 12/17/2022]
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12
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Christie MP, Simerská P, Jen FEC, Hussein WM, Rawi MFM, Hartley-Tassell LE, Day CJ, Jennings MP, Toth I. A drug delivery strategy: binding enkephalin to asialoglycoprotein receptor by enzymatic galactosylation. PLoS One 2014; 9:e95024. [PMID: 24736570 PMCID: PMC3988166 DOI: 10.1371/journal.pone.0095024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/21/2014] [Indexed: 11/23/2022] Open
Abstract
Glycosylation of biopharmaceuticals can mediate cell specific delivery by targeting carbohydrate receptors. Additionally, glycosylation can improve the physico-chemical (drug-like) properties of peptide based drug candidates. The main purpose of this study was to examine if glycosylation of the peptide enkephalin could facilitate its binding to the carbohydrate receptor, asialoglycoprotein. Firstly, we described the one-pot enzymatic galactosylation of lactose modified enkephalin in the presence of uridine-5'-diphosphogalactose 4-epimerase and lipopolysaccharyl α-1,4-galactosyltransferase. Stability experiments using human plasma and Caco-2 cell homogenates showed that glycosylation considerably improved the stability of enkephalin (at least 60% remained stable after a 2 hr incubation at 37°C). In vitro permeability experiments using Caco-2 cells revealed that the permeability of mono- and trisaccharide conjugated enkephalins was 14 and 28 times higher, respectively, than that of enkephalin alone (Papp 3.1×10-8 cm/s). By the methods of surface plasmon resonance and molecular modeling, we demonstrated that the enzymatic glycosylation of enkephalin enabled binding the asialoglycoprotein receptor. The addition of a trisaccharide moiety to enkephalin improved the binding of enkephalin to the asialoglycoprotein receptor two fold (KD = 91 µM). The docking scores from molecular modeling showed that the binding modes and affinities of the glycosylated enkephalin derivatives to the asialoglycoprotein receptor complemented the results from the surface plasmon resonance experiments.
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Affiliation(s)
- Michelle P. Christie
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Pavla Simerská
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Freda E.-C. Jen
- Institute for Glycomics, Griffith University, Southport, Queensland, Australia
| | - Waleed M. Hussein
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Mohamad F. M. Rawi
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | | | - Christopher J. Day
- Institute for Glycomics, Griffith University, Southport, Queensland, Australia
| | - Michael P. Jennings
- Institute for Glycomics, Griffith University, Southport, Queensland, Australia
| | - Istvan Toth
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
- School of Pharmacy, The University of Queensland, Pharmacy Australia Centre of Excellence, Woolloongabba, Queensland, Australia
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Simerska P, Christie MP, Goodwin D, Jen FEC, Jennings MP, Toth I. α-1,4-Galactosyltransferase-catalyzed glycosylation of sugar and lipid modified Leu-enkephalins. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.molcatb.2013.08.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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14
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Christie MP, Simerska P, Jen FEC, Jennings MP, Toth I. Liposomes for Improved Enzymatic Glycosylation of Lipid-Modified Lactose Enkephalin. Chempluschem 2013; 78:793-796. [PMID: 31986686 DOI: 10.1002/cplu.201300115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/04/2013] [Indexed: 01/17/2023]
Abstract
Liposomes and enzymes: Liposome formulations improved solubility of a lipid-modified lactose enkephalin and, when used in enzymatic transformation, led to a twofold increase in glycosylation in comparison to substrate solubilised in 5 % dimethyl sulfoxide (DMSO; see figure).
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Affiliation(s)
- Michelle P Christie
- School of Chemistry and Molecular Biosciences, The University of Queensland, Cooper Road, St Lucia, QLD 4072 (Australia), Fax: (+61) 7-33654273
| | - Pavla Simerska
- School of Chemistry and Molecular Biosciences, The University of Queensland, Cooper Road, St Lucia, QLD 4072 (Australia), Fax: (+61) 7-33654273
| | - Freda E-C Jen
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, QLD 4125 (Australia)
| | - Michael P Jennings
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, QLD 4125 (Australia)
| | - Istvan Toth
- School of Chemistry and Molecular Biosciences, The University of Queensland, Cooper Road, St Lucia, QLD 4072 (Australia), Fax: (+61) 7-33654273.,School of Pharmacy, The University of Queensland, Pharmacy Australia Centre of Excellence, Cornwall Street, Woolloongabba, QLD 4102 (Australia)
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15
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Oliveri V, Viale M, Caron G, Aiello C, Gangemi R, Vecchio G. Glycosylated copper(ii) ionophores as prodrugs for β-glucosidase activation in targeted cancer therapy. Dalton Trans 2013; 42:2023-34. [DOI: 10.1039/c2dt32429f] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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16
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Simerska P, Moyle PM, Toth I. Modern lipid-, carbohydrate-, and peptide-based delivery systems for peptide, vaccine, and gene products. Med Res Rev 2009; 31:520-47. [DOI: 10.1002/med.20191] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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17
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Arafa HMM. Possible contribution of beta-glycosidases and caspases in the cytotoxicity of novel glycoconjugates in colon cancer cells. Invest New Drugs 2009; 28:306-17. [PMID: 19415182 DOI: 10.1007/s10637-009-9248-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 03/23/2009] [Indexed: 11/30/2022]
Abstract
Glycoconjugates represent a recent trend in cancer chemotherapy that adopts the concept of selective prodrug/drug targeting of tumor cells by selectively binding to specific transmembrane glucose transporters. Following preferential uptake of sugar conjugates into cancer cells, they are presumably subject to enzymatic cleavage by specific beta-glycosidases to liberate the free active cytotoxic aglycones that act selectively on cancer cells and spare other noncancerous ones. In this sense, the cytotoxicity of an array of newly synthesized glycoconjugates, including curcumin beta-glucoside, perillyl alcohol beta-glucoside, perillyl alcohol beta-galactoside, diethylstilbesterol beta-glucoside and diethylstilbesterol beta-galactoside have been investigated over 24-96 h in a panel of human colon cancer cells namely, Caco-2, HT29 and T84 cells. The role of beta-glycosidases and caspases in the bioactivation and cytotoxicity of these compounds has been addressed in the current study. All the glycoconjugates have proven cytotoxic efficacy in a time-dependent manner. Curcumin beta-glucoside was the most potent amongst all glycoconjugates tested. The sensitivity rank order of tumor cells towards all beta-glucosides was Caco-2 > HT29 > T84. This sensitivity ranking was well correlated with beta-glucosidase activity assessed in these cell lines. Unlike perillyl alcohol galactoside, the cytotoxicity rank order for diethylstilbesterol beta-galactoside was not coping with the beta-galactosidase activity detected. Apoptosis was assessed by fluorometric assay of caspase-3 and caspase-9 activities. Initiation and activation of apoptosis were increased in all colon cancer cells following exposure to most of the glycoconjugates, and this was well correlated with the cytotoxicity rank order of these prodrugs. Enzymatic cleavage of glycoconjugates was accomplished using a host of hydrolytic enzymes and cleavage kinetics was determined using HPLC. The glycoconjugates were only cleaved by beta-glucosidases and beta-galactosidases, but not by pancreatic lipase or hepatic esterase. Taken together, one could conclude that beta-glucosidases and beta-galactosidases are crucial for the bioactivation and cytotoxicity of these glycoconjugates. Also, initiation and activation of apoptosis in tumor cells may contribute, at least partly, for the cytotoxicity of these sugar conjugates.
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Affiliation(s)
- Hossam M M Arafa
- Department of Pharmacol & Toxicol, Faculty of Pharmacy, Al-Azhar University, Nasr City, Cairo, Egypt.
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Otake K, Suzuki H, Higashi R, Yabuuchi H, Haga M, Maeda T, Cook TJ, Tamai I. Improved Intestinal Membrane Permeability of Hexose-Quinoline Derivatives via the Hexose Transporter, SGLT1. J Pharm Sci 2008; 97:1821-30. [PMID: 17828732 DOI: 10.1002/jps.21147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Intestinal membrane permeability is an important factor affecting the bioavailability of drugs. As a strategy to improve membrane permeability, membrane transporters are useful targets since essential nutrients are absorbed efficiently via specific transporters. For example, there are reports that intestinal hexose transporters could be used as a tool to improve permeability; however, there has been no direct evidence that the transporter protein, sodium/glucose cotransporter 1 (SGLT1), is involved in the transport of hexose analogs. Accordingly, we examined directly whether the intestinal membrane permeability of hexose analogs can be improved by utilizing SGLT1. Three hexose-quinoline derivatives were synthesized and their interactions with SGLT1 were evaluated. Among the three derivatives, the glucose-quinoline molecule exhibited an inhibitory effect on D-glucose uptake by both rat intestinal brush-border membrane vesicles (BBMVs) and Xenopus oocytes expressing SGLT1. In addition, significant uptake of the glucose-quinoline derivative by Xenopus oocytes expressing SGLT1 was observed by both an electrophysiological assay and direct measurement of the uptake of the compound, while the galactose-quinoline derivative did not show significant uptake via SGLT1. Thus, it was directly demonstrated that SGLT1 could be used as a tool for the improvement of intestinal membrane permeability of drugs by modification to the glucose analogs.
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Affiliation(s)
- Katsumasa Otake
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda, Chiba 278-8510, Japan
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19
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Bergeon JA, Chan YN, Charles BG, Toth I. Oral absorption enhancement of dipeptide L-Glu-L-Trp-OH by lipid and glycosyl conjugation. Biopolymers 2008; 90:633-43. [DOI: 10.1002/bip.21003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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20
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Tripoli E, Giammanco M, Tabacchi G, Di Majo D, Giammanco S, La Guardia M. The phenolic compounds of olive oil: structure, biological activity and beneficial effects on human health. Nutr Res Rev 2007; 18:98-112. [DOI: 10.1079/nrr200495] [Citation(s) in RCA: 428] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractThe Mediterranean diet is rich in vegetables, cereals, fruit, fish, milk, wine and olive oil and has salutary biological functions. Epidemiological studies have shown a lower incidence of atherosclerosis, cardiovascular diseases and certain kinds of cancer in the Mediterranean area. Olive oil is the main source of fat, and the Mediterranean diet's healthy effects can in particular be attributed not only to the high relationship between unsaturated and saturated fatty acids in olive oil but also to the antioxidant property of its phenolic compounds. The main phenolic compounds, hydroxytyrosol and oleuropein, which give extra-virgin olive oil its bitter, pungent taste, have powerful antioxidant activity bothin vivoandin vitro. The present review focuses on recent works analysing the relationship between the structure of olive oil polyphenolic compounds and their antioxidant activity. These compounds' possible beneficial effects are due to their antioxidant activity, which is related to the development of atherosclerosis and cancer, and to anti-inflammatory and antimicrobial activity.
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Oulianova N, Cheng D, Huebert N, Chen Y. Human oral drugs absorption is correlated to their in vitro uptake by brush border membrane vesicles. Int J Pharm 2006; 336:115-21. [PMID: 17178445 DOI: 10.1016/j.ijpharm.2006.11.045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 11/01/2006] [Accepted: 11/21/2006] [Indexed: 10/23/2022]
Abstract
Brush border membrane vesicles (BBMV) were prepared from the rabbit small intestine for testing drug absorption potency through the enterocyte's apical membrane, which is an important compartment for drug oral absorption. Some modifications have been made to the traditional vesicle assay for adapting it to the 96-well plate format. The accumulation of 23 reference drugs was measured, and the data showed a good correlation with human oral absorption with a correlation coefficient R=0.853 (P<0.001), with the exception of a few false positive results. As the measured drug absorption may contain a membrane/protein binding component as well as drug uptake into vesicles, these two fractions can be discriminated by changing extravesicular osmolarity using different mannitol concentrations. This model can be applied for evaluating drug absorption rate/mechanisms, and helping drug selection in early drug research and development.
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Affiliation(s)
- Nathalie Oulianova
- Biotechnology Research Institute, National Council of Canada, 6100 Royalmount, Montreal, Quebec H4P 2R2, Canada
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22
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Mizuma T. Drug delivery system based on transport characteristics of biological membranes Drug delivery system utilizing sugar transporter. ACTA ACUST UNITED AC 2006. [DOI: 10.2745/dds.21.126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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23
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Zhou N, Liu Y, Zhou GJ, Zhao YF. One pot conjugation of the polypeptides directed by phosphorus oxychloride. ACTA ACUST UNITED AC 2005; 65:427-32. [PMID: 15813889 DOI: 10.1111/j.1399-3011.2005.00231.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A series of homopeptides and their conjugates were synthesized in one pot reaction in the presence of phosphorus oxychloride and the conjugate yield was structurally dependent. Menthol and benzylamine conjugated to the homopeptides quantitatively. Homopeptides when treated with diisopropyloxyphosphite (DIPPH) and NaClO yield the corresponding N-phosphoryl peptides. Electrospray ionization-mass spectrometry (ESI-MS)/MS was used to study the structure of peptide conjugates. This paper reports a simple method to synthesize the homopeptides and their conjugate derivatives and the fact that phosphoryl peptides could also be obtained by one pot reaction.
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Affiliation(s)
- N Zhou
- College of Chemistry and Engineering, Xiamen University, Xiamen, China
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24
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Schottelius M, Rau F, Reubi JC, Schwaiger M, Wester HJ. Modulation of Pharmacokinetics of Radioiodinated Sugar-Conjugated Somatostatin Analogues by Variation of Peptide Net Charge and Carbohydration Chemistry. Bioconjug Chem 2005; 16:429-37. [PMID: 15769098 DOI: 10.1021/bc0499228] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sugar conjugation of biooactive peptides has been shown to be a powerful tool to modulate peptide pharmacokinetics. In the case of radiolabeled somatostatin analogues developed for in vivo scintigraphy of somatostatin receptor (sst) expressing tumors, it generally led to tracers with predominant renal excretion and low uptake in nontarget organs, and in some cases also with enhanced tumor accumulation. Especially with respect to endoradiotherapeutic applicability of these tracers, however, understanding the structural requirements for minimal kidney accumulation and maximal tumor uptake is important. The aim of this study was therefore the evaluation of the potential of specific glycoside structures in combination with reduced peptide net charge to reduce kidney accumulation without affecting tumor accumulation. Three glyco analogues of radioiodinated Tyr(3)-octreotate (TOCA) with z = 0 were evaluated in a comparative study using [(125)I]Mtr-TOCA (z = +1), the maltotriose-Amadori analogue of [(125)I]TOCA, as a reference, [(125)I]Glucuron-TOCA, the Amadori conjugate with glucuronic acid, and [(125)I]Gluc-S- and [(125)I]Gal-S-TOCA, the coupling products with glucosyl- and mannosyl-mercaptopropionate. In cells transfected with sst(1)-sst(5), all three new analogues show sst-subtype binding profiles similar to I-Mtr-TOCA with high, but somewhat reduced, affinity for sst(2). In contrast, internalization into sst(2)-expressing cells (in % of [(125)I]Tyr(3)-octreotide ([(125)I]TOC)) as well as the EC(50,R) of unlabeled TOC for internalization determined in dual-tracer experiments are substantially enhanced for [(123)I]Gal-S-TOCA and [(123)I]Gluc-S-TOCA (internalization, 190% +/- 12% and 265% +/- 20%, respectively, vs 168% +/- 6% of [(125)I]TOC for [(123)I]Mtr-TOCA; EC(50,R), 2.62 +/- 0.07 and 2.96 +/- 0.14, respectively, vs 1.81 +/- 0.07 for [(123)I]Mtr-TOCA). The tumor accumulation of [(125)I]Gal-S-TOCA and [(125)I]Gluc-S-TOCA in AR42J tumor-bearing nude mice 1 h p.i. is consequently very high (22.6 +/- 2.2 and 26.2 +/- 5.6%ID/g) and comparable to that of [(125)I]Mtr-TOCA (25.1 +/- 4.4%ID/g). [(125)I]Glucuron-TOCA showed lower uptake in sst-expressing tissues than did [(125)I]Mtr-TOCA, but considerably enhanced accumulation in nontarget organs such as liver, intestine, and kidney. Due to increased lipophilicity, hepatic and intestinal uptake 1 and 4 h p.i. of [(125)I]Gal-S-TOCA and [(125)I]Gluc-S-TOCA was also slightly higher than that of [(125)I]Mtr-TOCA. Kidney accumulation, however, was reduced by approximately 50% for both compounds (2.6 +/- 0.3 and 2.2 +/- 0.4, respectively, vs 4.0 +/- 0.7%ID/g at 1 h p.i.). Because no sugar-specific effect was detected in the latter case, it is concluded that general ligand pharmacokinetics and especially kidney accumulation of the tracers investigated are mainly determined by physicochemical characteristics such as lipophilicity, net charge, and also charge distribution ([(125)I]Glucuron-TOCA vs [(125)I]Gal-S- and [(125)I]Gluc-S-TOCA). With respect to receptor targeting, however, the structure of the carbohydrate moiety plays an important role, leading to dramatically enhanced ligand internalization, especially in the case of [(123)I]Gluc-S-TOCA. Taking into account the combined effects of the Gluc-S-moiety both on kidney and on tumor accumulation, this group seems to be a promising synthon for the synthesis of other radiolabeled peptide analogues with improved pharmacokinetics.
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Affiliation(s)
- Margret Schottelius
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany
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25
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Steffansen B, Nielsen CU, Brodin B, Eriksson AH, Andersen R, Frokjaer S. Intestinal solute carriers: an overview of trends and strategies for improving oral drug absorption. Eur J Pharm Sci 2004; 21:3-16. [PMID: 14706808 DOI: 10.1016/j.ejps.2003.10.010] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A large amount of absorptive intestinal membrane transporters play an important part in absorption and distribution of several nutrients, drugs and prodrugs. The present paper gives a general overview on intestinal solute carriers as well as on trends and strategies for targeting drugs and/or prodrugs to these carriers in order to increasing oral bioavailability and distribution. A number of absorptive intestinal transporters are described in terms of gene and protein classification, driving forces, substrate specificities and cellular localization. When targeting absorptive large capacity membrane transporters in the small intestine in order to increase oral bioavailabilities of drug or prodrug, the major influence on in vivo pharmacokinetics is suggested to be dose-dependent increase in bioavailability as well as prolonged blood circulation due to large capacity facilitated absorption, and renal re-absorption, respectively. In contrast, when targeting low-capacity transporters such as vitamin transporters, dose independent saturable absorption kinetics are suggested. We thus believe that targeting drug substrates for absorptive intestinal membrane transporters could be a feasible strategy for optimizing drug bioavailability and distribution.
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Affiliation(s)
- Bente Steffansen
- Department of Pharmaceutics, The Danish University of Pharmaceutical Sciences, 2 Universitetsparken, DK-2100 Copenhagen, Denmark.
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26
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Wester HJ, Schottelius M, Poethko T, Bruus-Jensen K, Schwaiger M. Radiolabeled Carbohydrated Somatostatin Analogs: A Review of the Current Status. Cancer Biother Radiopharm 2004; 19:231-44. [PMID: 15186604 DOI: 10.1089/108497804323072011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
During the last decade, peptide radiopharmaceuticals have become an important class of tracers for the detection and localization of malignant neoplasms by peptide receptor imaging (PRI) and for therapeutic intervention by peptide receptor radiotherapy (PRRT). Various radiometalated peptides have entered detailed clinical studies or found broad application for peptide receptor radiotherapy. In contrast, radiohalogenated peptides could not benefit from this development. Especially with respect to the growing number of peptidic structures with high receptor affinity and the increasing demand for means of corresponding receptor status quantification for therapy planning and control, the development of methods for the improved availability of 18F-labeled peptides for positron emission tomography imaging is still a very important objective in radiopharmaceutical research. Consequently, as part of our ongoing efforts in this field, we investigated the potential of carbohydration as a valuable tool to modify pharmacokinetics of peptides and evaluated the influence of this modification on the in vitro and in vivo behavior of octreotide analogs. Furthermore, a new methodology is presented allowing for the fast and straightforward labeling of peptides in a chemoselective manner. This combined approach to the chemoselective conjugation of unprotected, carbohydrated peptides seems to have the potential for a redirection and reevaluation of the future of radiohalogenated peptides in nuclear medicine.
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Affiliation(s)
- Hans-Jürgen Wester
- Department of Nuclear Medicine, Technical University Munich, Munich, Germany.
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27
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Sugawara M, Kato M, Kitakubo M, Takekuma Y, Ganapathy V, Miyazaki K. Inhibitory Effects of Basic Drugs on the Sodium-Dependent Transport of L-Alanine via System B0 in the Small Intestine. Drug Metab Pharmacokinet 2003; 18:186-93. [PMID: 15618734 DOI: 10.2133/dmpk.18.186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To elucidate the mechanism of the interaction of basic drugs with Na(+)-dependent L-alanine absorption from the small intestine, we investigated the effect of imipramine on the transport of L-alanine via system B(0), which is thought to be one of the main Na(+)-dependent systems for intestinal absorption of short-chain neutral amino acids, including L-alanine. The uptake of L-alanine by cells that express hATB(0) (human amino acid transporter B(0)) was inhibited in the presence of imipramine. The Eadie-Hofstee plot showed that the inhibition was not competitive with the substrate (L-alanine) but competitive with Na(+). When rat intestinal brush border membrane vesicles were used, several basic drugs had inhibitory effects. Inhibition was also observed in intestinal absorption evaluated by an in situ single-pass perfusion technique. However, the potencies of inhibition were different. The potency of inhibition was dependent on the lipophilicity of the drugs.
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Affiliation(s)
- Mitsuru Sugawara
- Department of Pharmacy, Hokkaido University Hospital, School of Medicine, Hokkaido University, Sapporo, Japan
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28
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29
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Schottelius M, Wester HJ, Reubi JC, Senekowitsch-Schmidtke R, Schwaiger M. Improvement of pharmacokinetics of radioiodinated Tyr(3)-octreotide by conjugation with carbohydrates. Bioconjug Chem 2002; 13:1021-30. [PMID: 12236784 DOI: 10.1021/bc0200069] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Among a variety of other factors, the clearance kinetics and routes of excretion of radiopharmaceuticals are of crucial importance for early and high tumor/background ratios and thus signal intensity in diagnostic imaging by single photon emission tomography (SPECT) or positron emission tomography (PET). To overcome the unfavorable pharmacokinetics of radiohalogenated octreotide analogues, we evaluated three carbohydrated conjugates of Tyr(3)-octreotide (TOC). Glucose ([(125)I]Gluc-TOC), maltose ([(125)I]Malt-TOC), and maltotriose ([(125)I]Mtr-TOC) derivatives of [(125)I]TOC were synthesized via Maillard reaction and subsequent radioiodination. In cells transfected with sst1-sst5, I-Malt-TOC, and I-Mtr-TOC show sst-subtype binding profiles similar to I-TOC with high affinity for sst2. Comparative biodistribution studies 10, 30, and 60 min pi in nude mice bearing rat pancreatic tumor xenografts showed fast blood clearance for all glycosylated derivatives. Due to their markedly increased hydrophilicity, [(125)I]Gluc-TOC and [(125)I]Malt-TOC were mainly cleared via the kidneys, which led to a significant decrease in activity accumulation in liver and intestine (5.3 and 1.4 versus 10.6%ID/g for [(125)I]TOC in the liver, 1.7 and 1.0 versus 3.8%ID/g for [(125)I]TOC in the intestine 60 min pi). For all compounds, hydrophilicity and uptake in liver and intestines correlate. Uptake of the carbohydrate conjugates in the kidney was comparable. Compared to the parent compound, the accumulation of the carbohydrated compounds in sst-rich tissues (pancreas, adrenals) was increased by a factor of 1.5-3.5. While tumor uptake of [(125)I]TOC (6.7 +/- 2.6%ID/g), [(125)I]Malt-TOC (5.3 +/- 1.9%ID/g), and [(125)I]Mtr-TOC (4.9 +/- 2.2%ID/g) at 30 min postinjection was comparable, accumulation of [(125)I]Gluc-TOC was significantly increased (10.1 +/- 2.8%ID/g at 30 min pi). Somatostatin receptor specificity of tumor uptake was confirmed by pretreatment, competition, and displacement experiments in vivo using 0.8 mg TOC/kg and gamma-camera imaging. Glycosylation proved to be a powerful tool for the development of high affinity sst ligands with excellent excretion profiles and improved tumor accumulation.
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Affiliation(s)
- Margret Schottelius
- Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany
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30
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Abstract
Peptide and protein drugs are becoming a very important class of therapeutic agents. However, the oral bioavailability of peptide and protein drugs is generally poor because they are extensively degraded by proteases in the gastrointestinal tract or impermeable through the intestinal mucosa. For the systemic delivery of the peptide and protein drugs, parenteral administration is currently required to achieve their therapeutic activities. However, this administration is poorly accepted by patients and may cause allergic reactions and serious side effects. Therefore, various approaches have been examined to overcome the delivery problems of these peptides when they are administered into the gastrointestinal tract and other mucosal sites. These approaches include (1) to use additives such as absorption enhancers and protease inhibitors, (2) to develop an administration method for peptides that can serve as an alternative to oral and injection administration, (3) to modify the molecular structure of peptide and protein drugs to produce prodrugs and analogues, and (4) to use the dosage forms to these peptide drugs. In this study, we demonstrated that the transmucosal absorption of various peptides including insulin, calcitonin, tetragastrin and thyrotropin releasing hormone (TRH) could be improved by the use of these approaches. Therefore, these approaches may give us basic information to improve the transmucosal absorption of peptide and protein drugs.
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Affiliation(s)
- A Yamamoto
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan
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31
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Witt KA, Gillespie TJ, Huber JD, Egleton RD, Davis TP. Peptide drug modifications to enhance bioavailability and blood-brain barrier permeability. Peptides 2001; 22:2329-43. [PMID: 11786210 DOI: 10.1016/s0196-9781(01)00537-x] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptides have the potential to be potent pharmaceutical agents for the treatment of many central nervous system derived maladies. Unfortunately peptides are generally water-soluble compounds that will not enter the central nervous system, via passive diffusion, due to the existence of the blood-brain barrier. Peptides can also undergo metabolic deactivation by peptidases, thus further reducing their therapeutic benefits. In targeting peptides to the central nervous system consideration must be focused both on increasing bioavailability and enhancing brain uptake. To date multiple strategies have been examined with this focus. However, each strategy comes with its own complications and considerations. In this review we assess the strengths and weaknesses of many of the methods currently being examined to enhance peptide entry into the central nervous system.
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Affiliation(s)
- K A Witt
- Department of Pharmacology, The University of Arizona, College of Medicine, LSN 542, 1501 N. Campbell Avenue, Tucson, Arizona 85724, USA
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32
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Mitchell SA, Pratt MR, Hruby VJ, Polt R. Solid-phase synthesis of O-linked glycopeptide analogues of enkephalin. J Org Chem 2001; 66:2327-42. [PMID: 11281773 DOI: 10.1021/jo005712m] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis of 18 N-alpha-FMOC-amino acid glycosides for solid-phase glycopeptide assembly is reported. The glycosides were synthesized either from the corresponding O'Donnell Schiff bases or from N-alpha-FMOC-amino protected serine or threonine and the appropriate glycosyl bromide using Hanessian's modification of the Koenigs-Knorr reaction. Reaction rates of D-glycosyl bromides (e.g., acetobromoglucose) with the L- and D-forms of serine and threonine are distinctly different and can be rationalized in terms of the steric interactions within the two types of diastereomeric transition states for the D/L and D/D reactant pairs. The N-alpha-FMOC-protected glycosides [monosaccharides Xyl, Glc, Gal, Man, GlcNAc, and GalNAc; disaccharides Gal-beta(1-4)-Glc (lactose), Glc-beta(1-4)-Glc (cellobiose), and Gal-alpha(1-6)-Glc (melibiose)] were incorporated into 22 enkephalin glycopeptide analogues. These peptide opiates bearing the pharmacophore H-Tyr-c[DCys-Gly-Phe-DCys]- were designed to probe the significance of the glycoside moiety and the carbohydrate-peptide linkage region in blood-brain barrier (BBB) transport, opiate receptor binding, and analgesia.
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Affiliation(s)
- S A Mitchell
- Department of Chemistry, The University of Arizona, Tucson, Arizona 85721, USA
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33
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Edgecombe SC, Stretch GL, Hayball PJ. Oleuropein, an antioxidant polyphenol from olive oil, is poorly absorbed from isolated perfused rat intestine. J Nutr 2000; 130:2996-3002. [PMID: 11110859 DOI: 10.1093/jn/130.12.2996] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Epidemiological studies have shown that the incidence of heart disease and certain cancers is lower in the Mediterranean region. This has been attributed to the high consumption of olive oil in the Mediterranean diet, which contains polyphenolic compounds with antioxidant activity. Although many in vitro studies have been performed to elucidate mechanisms by which these compounds may act, there are virtually no data relating to their fate after ingestion. Therefore, we decided to investigate the intestinal absorption of one of the major olive oil polyphenolics, oleuropein. To do this, a novel in situ intestinal perfusion technique was developed, and the absorption of oleuropein was studied under both iso-osmotic and hypotonic luminal conditions. Oleuropein was absorbed, with an apparent permeability coefficient (P:(app)) of 1.47 +/- 0.13 x 10(-6) cm/s (+/-SE) observed under iso-osmotic conditions. The mechanism of absorption is unclear but may involve transcellular transport (SGLT1) or paracellular movement. Under hypotonic conditions, the permeability of oleuropein was significantly greater (5.92 +/- 0.49 x 10(-6) cm/s, P: < 0.001). This increase is thought to be due to an increase in paracellular movement facilitated by the opening of paracellular junctions in response to hypotonicity. Overall, we determined that the olive oil polyphenolic oleuropein can be absorbed, albeit poorly, from isolated perfused rat intestine. Therefore, it is possible that it or its metabolites may confer a positive health benefit after the consumption of olive oil, most likely via an antioxidant mechanism.
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Affiliation(s)
- S C Edgecombe
- Centre for Pharmaceutical Research, University of South Australia, North Terrace, Adelaide, South Australia, 5000, Australia
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34
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Abstract
Despite the omnipresence of protein glycosylation in nature, little is known about how the attachment of carbohydrates affects peptide and protein activity. One reason is the lack of a straightforward method to access biologically relevant glycopeptides and glycoproteins. The isolation of homogeneous glycopeptides from natural sources is complicated by the heterogeneity of naturally occuring glycoproteins. It is chemical and chemoenzymatic synthesis that is meeting the challenge to solve this availability problem, thus playing a key role for the advancement of glycobiology. The current art of glycopeptide synthesis, albeit far from being routine, has reached a level of maturity that allows for the access to homogeneous and pure material for biological and medicinal research. Even the ambitious goal of the total synthesis of an entire glycoprotein is within reach. It is demonstrated that with the help of synthetic glycopeptides the effects of glycosylation on protein structure and function can be studied in molecular detail. For example, in immunology, synthetic (tumour-specific) glycopeptides can be used as immunogens to elicit a tumour-cell-specific immune response. Again, synthetic glycopeptides are an invaluable tool to determine the fine specificity of the immune response that can be mediated by both carbohydrate-specific B and T cells. Furthermore, selected examples for the use of synthetic glycopeptides as ligands of carbohydrate-binding proteins and as enzyme substrates or inhibitors are presented.
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Affiliation(s)
- O Seitz
- Department of Chemical Biology Max-Planck-Institut für molekulare Physiologie Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
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Egleton RD, Mitchell SA, Huber JD, Janders J, Stropova D, Polt R, Yamamura HI, Hruby VJ, Davis TP. Improved bioavailability to the brain of glycosylated Met-enkephalin analogs. Brain Res 2000; 881:37-46. [PMID: 11033091 DOI: 10.1016/s0006-8993(00)02794-3] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The blood-brain barrier prevents the entry of many potentially therapeutic peptide drugs to the brain. Glycosylation has shown potential as a methodology for improving delivery to the CNS. Previous studies have shown improved bioavailability and improved centrally mediated analgesia of glycosylated opioids. In this study we investigate the effect of glycosylation on the cyclic opioid peptide [D-Cys(2,5),Ser(6),Gly(7)] enkephalin. The peptide was glycosylated on the Ser(6) via an O-linkage with various sugar moieties and alignments. The peptides were then investigated for receptor binding, physiochemical attributes, in situ brain uptake in female Sprague-Dawley rats and antinociception in male ICR mice. Glycosylation resulted in a slight decrease in affinity to the delta-opioid receptor, and mixed effect on binding to the mu-opioid receptor. There was a significant decrease in lipophilicity resulting from glycosylation and a slight reduction in binding to bovine serum albumin. In situ perfusion showed that brain uptake was improved by up to 98% for several of the glycosylated peptides, and the nociceptive profiles of the peptides, in general, followed the rank order of peptide entry to the brain with up to a 39-fold increase in A.U.C.
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Affiliation(s)
- R D Egleton
- Department of Pharmacology, College of Medicine, University of Arizona, 1501 N. Campbell Ave., P.O. Box 245050, Tucson, AZ 85724, USA
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36
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Malkinson JP, Falconer RA, Toth I. Synthesis of C-terminal glycopeptides from resin-bound glycosyl azides via a modified Staudinger reaction. J Org Chem 2000; 65:5249-52. [PMID: 10993353 DOI: 10.1021/jo000381z] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The solid-phase synthesis of glycopeptides containing the sugar at the C-terminus is reported. The method is demonstrated on a model, the endogenous antinociceptive peptide Leu-enkephalin. 2,3,4-Tri-O-acetyl-1-azido-1-deoxy-beta-D-glucopyranuronic acid was synthesized and immobilized onto a variety of derivatized resins. Conjugation of the first amino acid was accomplished by reaction of the resin-bound glycosyl azide with an activated amino acid, in one step, via a modified Staudinger reaction. Standard solid-phase peptide synthesis then resulted in the desired amide-linked glycopeptide. Reaction conditions and reagents for the glycosylation were varied to optimize the yield and purity of the product. The optimum conditions were found to be the use of a 4-fold molar excess of activated amino acid and 3-fold excess of tri-n-butylphosphine in tetrahydrofuran. This methodology is generally applicable to most peptide sequences and is compatible with both Boc- and Fmoc- synthetic strategies on a variety of resins.
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Affiliation(s)
- J P Malkinson
- Department of Pharmaceutical and Biological Chemistry, The School of Pharmacy, University of London, UK
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37
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Tóth I, Malkinson JP, Flinn NS, Drouillat B, Horváth A, Erchegyi J, Idei M, Venetianer A, Artursson P, Lazorova L, Szende B, Kéri G. Novel lipoamino acid- and liposaccharide-based system for peptide delivery: application for oral administration of tumor-selective somatostatin analogues. J Med Chem 1999; 42:4010-3. [PMID: 10508449 DOI: 10.1021/jm9910167] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lipoamino acid and liposaccharide conjugates of somatostatin analogue TT-232 were synthesized to modify the physicochemical properties of the parent peptide. The relative position, the number, and the nature of the lipid and/or saccharide moieties were varied. Experiments in vitro clearly showed that many compounds modified at the N- and/or C-terminus with lipid or sugar moieties retained the biological activity of the parent compound. An interesting construct was synthesized containing lipid and sugar units at opposite ends of the somatostatin analogue, so that the entire molecule could be considered as an amphipathic surfactant.
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Affiliation(s)
- I Tóth
- Department of Pharmaceutical and Biological Chemistry, The School of Pharmacy, University of London, 20-39 Brunswick Square, London WC1N 1AX, U.K
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38
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Santos CA, Jacob JS, Hertzog BA, Freedman BD, Press DL, Harnpicharnchai P, Mathiowitz E. Correlation of two bioadhesion assays: the everted sac technique and the CAHN microbalance. J Control Release 1999; 61:113-22. [PMID: 10469908 DOI: 10.1016/s0168-3659(99)00109-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This contribution correlates two in vitro methods utilized to determine bioadhesion. One method, the everted intestinal sac technique, is a passive test for bioadhesion involving several polymer microspheres and a section of everted intestinal tissue. The other method, the CAHN microbalance, employs a CAHN dynamic contact angle analyzer with modified software to record the tensile forces measured as a single polymer microsphere is pulled from intestinal tissue. This study demonstrates that CAHN and everted sac experiments yield similar results when used to quantify the bioadhesive nature of polymer microsphere systems. A polymer showing high adhesion in one method also demonstrates high bioadhesion in the other method; polymers that exhibit high fracture strength and tensile work measurements with the CAHN microbalance also yield high binding percentages with the everted sac method. The polymers tested and reported here are poly(caprolactone) and different copolymer ratios of poly(fumaric-co-sebacic anhydride). The results of this correlation demonstrate that each method alone is a valuable indicator of bioadhesion.
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Affiliation(s)
- C A Santos
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Box G-B393, Providence, RI 02912, USA
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