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Chindamo G, Sapino S, Peira E, Chirio D, Gonzalez MC, Gallarate M. Bone Diseases: Current Approach and Future Perspectives in Drug Delivery Systems for Bone Targeted Therapeutics. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E875. [PMID: 32370009 PMCID: PMC7279399 DOI: 10.3390/nano10050875] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/16/2020] [Accepted: 04/19/2020] [Indexed: 12/14/2022]
Abstract
Bone diseases include a wide group of skeletal-related disorders that cause mobility limitations and mortality. In some cases, e.g., in osteosarcoma (OS) and metastatic bone cancer, current treatments are not fully effective, mainly due to low patient compliance and to adverse side effects. To overcome these drawbacks, nanotechnology is currently under study as a potential strategy allowing specific drug release kinetics and enhancing bone regeneration. Polymers, ceramics, semiconductors, metals, and self-assembled molecular complexes are some of the most used nanoscale materials, although in most cases their surface properties need to be tuned by chemical or physical reactions. Among all, scaffolds, nanoparticles (NPs), cements, and hydrogels exhibit more advantages than drawbacks when compared to other nanosystems and are therefore the object of several studies. The aim of this review is to provide information about the current therapies of different bone diseases focusing the attention on new discoveries in the field of targeted delivery systems. The authors hope that this paper could help to pursue further directions about bone targeted nanosystems and their application for bone diseases and bone regeneration.
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Affiliation(s)
- Giulia Chindamo
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (G.C.); (E.P.); (D.C.); (M.G.)
| | - Simona Sapino
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (G.C.); (E.P.); (D.C.); (M.G.)
| | - Elena Peira
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (G.C.); (E.P.); (D.C.); (M.G.)
| | - Daniela Chirio
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (G.C.); (E.P.); (D.C.); (M.G.)
| | - Mónica Cristina Gonzalez
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata 1900, Argentina;
| | - Marina Gallarate
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (G.C.); (E.P.); (D.C.); (M.G.)
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Farrell KB, Karpeisky A, Thamm DH, Zinnen S. Bisphosphonate conjugation for bone specific drug targeting. Bone Rep 2018; 9:47-60. [PMID: 29992180 PMCID: PMC6037665 DOI: 10.1016/j.bonr.2018.06.007] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 06/28/2018] [Accepted: 06/29/2018] [Indexed: 12/26/2022] Open
Abstract
Bones provide essential functions and are sites of unique biochemistry and specialized cells, but can also be sites of disease. The treatment of bone disorders and neoplasia has presented difficulties in the past, and improved delivery of drugs to bone remains an important goal for achieving effective treatments. Drug targeting strategies have improved drug localization to bone by taking advantage of the high mineral concentration unique to the bone hydroxyapatite matrix, as well as tissue-specific cell types. The bisphosphonate molecule class binds specifically to hydroxyapatite and inhibits osteoclast resorption of bone, providing direct treatment for degenerative bone disorders, and as emerging evidence suggests, cancer. These bone-binding molecules also provide the opportunity to deliver other drugs specifically to bone by bisphosphonate conjugation. Bisphosphonate bone-targeted therapies have been successful in treatment of osteoporosis, primary and metastatic neoplasms of the bone, and other bone disorders, as well as refining bone imaging. In this review, we focus upon the use of bisphosphonate conjugates with antineoplastic agents, and overview bisphosphonate based imaging agents, nanoparticles, and other drugs. We also discuss linker design potential and the current state of bisphosphonate conjugate research progress. Ongoing investigations continue to expand the possibilities for bone-targeted therapeutics and for extending their reach into clinical practice.
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Affiliation(s)
- Kristen B Farrell
- MBC Pharma Inc., 12635 East Montview Blvd., Aurora, CO 80045-0100, United States of America
| | - Alexander Karpeisky
- MBC Pharma Inc., 12635 East Montview Blvd., Aurora, CO 80045-0100, United States of America
| | - Douglas H Thamm
- Flint Animal Cancer Center, Colorado State University, 300 West Drake Road, Fort Collins, CO 80523-1620, United States of America
| | - Shawn Zinnen
- MBC Pharma Inc., 12635 East Montview Blvd., Aurora, CO 80045-0100, United States of America
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Yamashita S, Katsumi H, Sakane T, Yamamoto A. Bone-targeting dendrimer for the delivery of methotrexate and treatment of bone metastasis. J Drug Target 2018; 26:818-828. [DOI: 10.1080/1061186x.2018.1434659] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Shugo Yamashita
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, Japan
| | - Hidemasa Katsumi
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, Japan
| | - Toshiyasu Sakane
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, Japan
- Department of Pharmaceutical Technology, Kobe Pharmaceutical University, Higashinada-ku, Kobe, Japan
| | - Akira Yamamoto
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, Japan
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Yamashita S, Katsumi H, Hibino N, Isobe Y, Yagi Y, Kusamori K, Sakane T, Yamamoto A. Development of PEGylated carboxylic acid-modified polyamidoamine dendrimers as bone-targeting carriers for the treatment of bone diseases. J Control Release 2017; 262:10-17. [DOI: 10.1016/j.jconrel.2017.07.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 06/14/2017] [Accepted: 07/11/2017] [Indexed: 11/27/2022]
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Nadar RA, Margiotta N, Iafisco M, van den Beucken JJJP, Boerman OC, Leeuwenburgh SCG. Bisphosphonate-Functionalized Imaging Agents, Anti-Tumor Agents and Nanocarriers for Treatment of Bone Cancer. Adv Healthc Mater 2017; 6. [PMID: 28207199 DOI: 10.1002/adhm.201601119] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/23/2016] [Indexed: 12/14/2022]
Abstract
Bone metastases result from the invasion of primary tumors to bone. Current treatment modalities include local treatments such as surgery and radiotherapy, while systemic treatments include chemotherapy and (palliative) treatment of skeletal metastases. Nevertheless, once bone metastases have been established they remain incurable leading to morbidity and mortality. Bisphosphonates are a well-established class of drugs, which are increasingly applied in the treatment of bone cancers owing to their effective inhibition of tumor cells and suppression of bone metastases. The increased understanding of the mechanism of action of bisphosphonates on bone and tumor cells has prompted the development of novel bisphosphonate-functionalized imaging and therapeutic agents. This review provides an update on the preclinical efficacy of bisphosphonate-functionalized fluorophore, anti-tumor agents and nanocarriers for the treatment of bone metastases. After an overview of the general characteristics of bisphosphonates and their mechanisms of action, an outline is provided on the various conjugation strategies that have become available to functionalize imaging agents, anti-tumor agents and nanocarriers with bisphosphonates. Finally, the efficacy of these bisphosphonate-modified agents and carriers in preclinical studies is evaluated by reviewing their potential to target tumors and inhibit tumor growth in clinically relevant animal models for the treatment of bone cancer.
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Affiliation(s)
- Robin A. Nadar
- Department of Biomaterials; Radboud University Medical Center; Philips van Leydenlaan 25 6525 EX Nijmegen The Netherlands
| | - Nicola Margiotta
- Dipartimento di Chimica; Università degli Studi di Bari Aldo Moro; Via E. Orabona 4 70125 Bari Italy
| | - Michele Iafisco
- Institute of Science and Technology for Ceramics (ISTEC); National Research Council (CNR); Via Granarolo 64 48018 Faenza Italy
| | | | - Otto C. Boerman
- Department of Nuclear Medicine; Radboud University Medical Center; Geert Grooteplein Zuid 10 6525 AG Nijmegen The Netherlands
| | - Sander C. G. Leeuwenburgh
- Department of Biomaterials; Radboud University Medical Center; Philips van Leydenlaan 25 6525 EX Nijmegen The Netherlands
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Katsumi H, Sano JI, Nishikawa M, Hanzawa K, Sakane T, Yamamoto A. Molecular Design of Bisphosphonate-Modified Proteins for Efficient Bone Targeting In Vivo. PLoS One 2015; 10:e0135966. [PMID: 26287482 PMCID: PMC4545940 DOI: 10.1371/journal.pone.0135966] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 07/28/2015] [Indexed: 11/18/2022] Open
Abstract
To establish a rational molecular design for bisphosphonate (BP)-modified proteins for efficient bone targeting, a pharmacokinetic study was performed using a series of alendronate (ALN), a nitrogen-containing BP, modified proteins with various molecular weights and varying degrees of modification. Four proteins with different molecular weight—yeast glutathione reductase (GR; MW: 112,000 Da), bovine serum albumin (BSA; MW: 67,000 Da), recombinant human superoxide dismutase (SOD; MW: 32,000 Da), and chicken egg white lysozyme (LZM; MW: 14,000 Da)—were modified with ALN to obtain ALN-modified proteins. Pharmacokinetic analysis of the tissue distribution of the ALN-modified and unmodified proteins was performed after radiolabeling them with indium-111 (111In) by using a bifunctional chelating agent. Calculation of tissue uptake clearances revealed that the bone uptake clearances of 111In-ALN-modified proteins were proportional to the degree of ALN modification. 111In-GR-ALN and BSA-ALN, the two high-molecular-weight proteins, efficiently accumulated in bones, regardless of the degree of ALN modification. Approximately 36 and 34% of the dose, respectively, was calculated to be delivered to the bones. In contrast, the maximum amounts taken up by bone were 18 and 13% of the dose for 111In-SOD-ALN(32) and LZM-ALN(9), respectively, because of their high renal clearance. 111In-SOD modified with both polyethylene glycol (PEG) and ALN (111In-PEG-SOD-ALN) was efficiently delivered to the bone. Approximately 36% of the dose was estimated to be delivered to the bones. In an experimental bone metastasis mouse model, treatment with PEG-SOD-ALN significantly reduced the number of tumor cells in the bone of the mice. These results indicate that the combination of PEG and ALN modification is a promising approach for efficient bone targeting of proteins with a high total-body clearance.
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Affiliation(s)
- Hidemasa Katsumi
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Kyoto, Japan
- * E-mail:
| | - Jun-ichi Sano
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Makiya Nishikawa
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Keiko Hanzawa
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Toshiyasu Sakane
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Akira Yamamoto
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Kyoto, Japan
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Becker CS, Chukanov NV, Grigor’ev IA. New Amino-Bisphosphonate Building Blocks in the Synthesis of Bisphosphonic Derivatives Based on Lead Compounds. PHOSPHORUS SULFUR 2015. [DOI: 10.1080/10426507.2014.979989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Christina S. Becker
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Novosibirsk, Russian Federation
- Novosibirsk State University, Novosibirsk, Russian Federation
| | - Nikita V. Chukanov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Novosibirsk, Russian Federation
- Novosibirsk State University, Novosibirsk, Russian Federation
| | - Igor A. Grigor’ev
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Novosibirsk, Russian Federation
- Academician E.N. Meshalkin State Research Institute of Circulation Pathology, Novosibirsk, Russian Federation
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Ossipov DA. Bisphosphonate-modified biomaterials for drug delivery and bone tissue engineering. Expert Opin Drug Deliv 2015; 12:1443-58. [PMID: 25739860 DOI: 10.1517/17425247.2015.1021679] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Bisphosphonates (BPs) were introduced 45 years ago as anti-osteoporotic drugs and during the last decade have been utilized as bone-targeting groups in systemic treatment of bone diseases. Very recently, strategies of chemical immobilization of BPs in hydrogels and nanocomposites for bone tissue engineering emerged. These strategies opened new applications of BPs in bone tissue engineering. AREAS COVERED Conjugates of BPs to different drug molecules, imaging agents, proteins and polymers are discussed in terms of specific targeting to bone and therapeutic affect induced by the resulting prodrugs in comparison with the parent drugs. Conversion of these conjugates into hydrogel scaffolds is also presented along with the application of the resulting materials for bone tissue engineering. EXPERT OPINION Calcium-binding properties of BPs can be successfully extended via different conjugation strategies not only for purposes of bone targeting, but also in supramolecular assembly affording either new nanocarriers or bulk nanocomposite scaffolds. Interaction between carrier-linked BPs and drug molecules should also be considered for the control of release of these molecules and their optimized delivery. Bone-targeting properties of BP-functionalized nanomaterials should correspond to bone adhesive properties of their bulk analogs.
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Affiliation(s)
- Dmitri A Ossipov
- Uppsala University, Division of Polymer Chemistry, Department of Chemistry-Ångström, Science for Life Laboratory , Uppsala, SE 751 21 , Sweden +46 18 417 7335 ;
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Popwell SJ, Schulz MD, Wagener KB, Batich CD, Milner RJ, Lagmay J, Bolch WE. Synthesis of polymeric phosphonates for selective delivery of radionuclides to osteosarcoma. Cancer Biother Radiopharm 2014; 29:273-82. [PMID: 25111903 DOI: 10.1089/cbr.2014.1615] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Discussed in detail is the synthesis and primary structure characterization of two polymers aimed at advancing the treatment of pediatric osteosarcoma. These polymers are designed to systemically deliver radiometals specifically to osteosarcomas using the passive targeting mechanism of enhanced permeability and retention (the EPR effect). The approach begins with the synthesis of a polymer capable of binding radiometals, for which prior data show improved site-specific targeting of solid tumors. Building on this success, a second polymer has been designed for improving the efficacy of currently available radionuclide therapies by incorporating the FDA-approved small-molecule ligand Quadramet directly onto the polymer structure. Time-activity curves of the phosphonate-functionalized polymers show rapid clearance from the central compartment and nontargeted organs, with up to 65% of injected activity being excreted within 3 hours. Both polymer ligands demonstrate good osteosarcoma targeting capability with little to no uptake in organs associated with the dose-limiting bone marrow. Additionally, biodistribution studies in nonosseous tumor models demonstrate the tumor targeting mechanism of the polymer ligands, which appears to be influenced by the high affinity of the phosphonate functionality for the positively charged hydroxyapatite mineral found in bone tumors.
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Affiliation(s)
- Sam J Popwell
- 1 Department of Materials Science and Engineering, University of Florida , Gainesville, FL
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Gundogdu E, Ilem-Ozdemir D, Asikoglu M. In vitro incorporation studies of 99mTc–alendronate sodium at different bone cell lines. J Radioanal Nucl Chem 2013. [DOI: 10.1007/s10967-013-2833-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Methylene diphosphonate-conjugated adriamycin liposomes: preparation, characteristics, and targeted therapy for osteosarcomas in vitro and in vivo. Biomed Microdevices 2012; 14:497-510. [DOI: 10.1007/s10544-011-9626-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Yewle JN, Puleo DA, Bachas LG. Enhanced affinity bifunctional bisphosphonates for targeted delivery of therapeutic agents to bone. Bioconjug Chem 2011; 22:2496-506. [PMID: 22073906 PMCID: PMC3247145 DOI: 10.1021/bc2003132] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Skeletal diseases have a major impact on the worldwide population and economy. Although several therapeutic agents and treatments are available for addressing bone diseases, they are not being fully utilized because of their uptake in nontargeted sites and related side effects. Active targeting with controlled delivery is an ideal approach for treatment of such diseases. Because bisphosphonates are known to have high affinity to bone and are being widely used in treatment of osteoporosis, they are well-suited for drug targeting to bone. In this study, a targeted delivery of therapeutic agent to resorption sites and wound healing sites of bone was explored. Toward this goal, bifunctional hydrazine-bisphosphonates (HBPs), with spacers of various lengths, were synthesized and studied for their enhanced affinity to bone. Crystal growth inhibition studies showed that these HBPs have high affinity to hydroxyapatite, and HBPs with shorter spacers bind more strongly than alendronate to hydroxyapatite. The HBPs did not affect proliferation of MC3T3-E1 preosteoblasts, did not induce apoptosis, and were not cytotoxic at the concentration range tested (10(-6)-10(-4) M). Furthermore, drugs can be linked to the HBPs through a hydrazone linkage that is cleavable at the low pH of bone resorption and wound healing sites, leading to release of the drug. This was demonstrated using hydroxyapatite as a model material of bone and 4-nitrobenzaldehyde as a model drug. This study suggests that these HBPs could be used for targeted delivery of therapeutic agents to bone.
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Affiliation(s)
- Jivan N. Yewle
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055
| | - David A. Puleo
- Center for Biomedical Engineering, University of Kentucky, Lexington, Kentucky 40506-0070
| | - Leonidas G. Bachas
- Delpartment of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146-0431
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Lacerda S, Marques F, Campello P, Gano L, Kubíček V, Hermann P, Santos I. Chemical, radiochemical and biological studies of Sm and Ho complexes of H4dota analogues containing one methylphosphonic/phosphinic acid pendant arm. J Labelled Comp Radiopharm 2009. [DOI: 10.1002/jlcr.1697] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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de Rosales RTM, Finucane C, Mather SJ, Blower PJ. Bifunctional bisphosphonate complexes for the diagnosis and therapy of bone metastases. Chem Commun (Camb) 2009:4847-9. [PMID: 19652801 PMCID: PMC7116767 DOI: 10.1039/b908652h] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Easily synthesised and structurally well-defined novel imaging/therapeutic radiopharmaceutical agents for bone metastases are described.
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Affiliation(s)
- R. Torres Martin de Rosales
- Division of Imaging Sciences, The Rayne Institute, King’s College London, 4th Floor Lambeth Wing, St. Thomas Hospital, London, UK SE1 7EH. Fax: +44 (0)2071885442; Tel: +44 (0)2071889513
| | - C. Finucane
- Centre for Molecular Oncology and Imaging, Institute of Cancer, Barts and The London School of Medicine, John Vane Science Centre, Charterhouse Square, London, UK EC1M 6BQ. Fax: +44 (0)2070140431; Tel: +44 (0)2070140467
| | - S. J. Mather
- Centre for Molecular Oncology and Imaging, Institute of Cancer, Barts and The London School of Medicine, John Vane Science Centre, Charterhouse Square, London, UK EC1M 6BQ. Fax: +44 (0)2070140431; Tel: +44 (0)2070140467
| | - P. J. Blower
- Division of Imaging Sciences, The Rayne Institute, King’s College London, 4th Floor Lambeth Wing, St. Thomas Hospital, London, UK SE1 7EH. Fax: +44 (0)2071885442; Tel: +44 (0)2071889513
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El-Mabhouh AA, Mercer JR. 188Re-labelled gemcitabine/bisphosphonate (Gem/BP): a multi-functional, bone-specific agent as a potential treatment for bone metastases. Eur J Nucl Med Mol Imaging 2008; 35:1240-8. [PMID: 18265977 DOI: 10.1007/s00259-008-0728-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 01/22/2008] [Indexed: 10/22/2022]
Abstract
PURPOSE This study investigated the bone-binding affinity and biodistribution of a (188)Re-labelled gemcitabine/bisphosphonate (Gem/BP) conjugate, a multi-functional drug designed to deliver tumour-specific combined radiotherapy and chemotherapy to the bone using the high bone-binding affinity of the bisphosphonate group. METHODS The Gem/BP conjugate was labelled at high radiochemical purity with (188)Re. The bone-binding affinity of the (188)Re-Gem/BP was studied in vitro in purified hydroxyapatite emulsion and powdered bovine bone. In vivo biodistribution studies were carried out in normal BALB/c mice. RESULTS (188)Re-Gem/BP demonstrated strong and stable binding in both in vitro systems. In vivo (188)Re-Gem/BP showed bone uptake, rapid blood clearance and rapid elimination of unbound activity. The bone tissue demonstrated the highest concentration of bound radioactivity exempting the kidneys. Approximately 67% of retained whole-body activity was bound to the bone at 8 h after (188)Re-Gem/BP administration. CONCLUSIONS (188)Re-Gem/BP demonstrated high, selective and persistent bone binding and can be considered as a model compound for multi-functional bone-specific therapy for bone metastases.
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Affiliation(s)
- Amal A El-Mabhouh
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada T6G-2N8
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El-Mabhouh AA, Angelov CA, Cavell R, Mercer JR. A 99mTc-labeled gemcitabine bisphosphonate drug conjugate as a probe to assess the potential for targeted chemotherapy of metastatic bone cancer. Nucl Med Biol 2006; 33:715-22. [PMID: 16934690 DOI: 10.1016/j.nucmedbio.2006.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 06/14/2006] [Accepted: 06/15/2006] [Indexed: 10/24/2022]
Abstract
INTRODUCTION A novel compound with the potential for "targeted" therapy for cancer patients was prepared using a conjugate between the potent anticancer drug Gemzar (gemcitabine) and a bisphosphonate. This conjugate would be expected to accumulate at sites of bone metastatic cancer by virtue of an affinity of the bisphosphonate for bone undergoing osteoclastic and osteoblastic remodeling. Release of the anticancer drug at the site of the tumor would provide high local concentrations of the drug but avoid systemic toxicity. METHODS The conjugate was tested for bone binding by labeling with technetium-99m and using an in vitro test procedure with either purified hydroxyapatite (HA) or powdered bovine bone. Biodistribution and pharmacokinetic studies in mice were used to determine the excretion and bone-binding characteristics of the test compound. RESULTS AND CONCLUSIONS The conjugate binds readily to powdered bone and HA using the in vitro test systems. In animal studies, the conjugate is found predominantly in bone with low soft tissue uptake after intravenous dosing. Unbound compound undergoes renal excretion. The gemcitabine bisphosphonate complex is a promising lead compound for investigation in metastatic bone cancer that may provide a therapeutic effect without undue toxicity.
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Affiliation(s)
- Amal A El-Mabhouh
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta T6G 2N8, Canada
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