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Evaluation of Aminopolycarboxylate Chelators for Whole-Body Clearance of Free 225Ac: A Feasibility Study to Reduce Unexpected Radiation Exposure during Targeted Alpha Therapy. Pharmaceutics 2021; 13:pharmaceutics13101706. [PMID: 34683999 PMCID: PMC8540721 DOI: 10.3390/pharmaceutics13101706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/06/2021] [Accepted: 10/12/2021] [Indexed: 11/24/2022] Open
Abstract
Actinium-225 (225Ac) is a promising radionuclide used in targeted alpha therapy (TAT). Although 225Ac labeling of bifunctional chelating ligands is effective, previous in vivo studies reported that free 225Ac can be released from the drugs and that such free 225Ac is predominantly accumulated in the liver and could cause unexpected toxicity. To accelerate the clinical development of 225Ac TAT with a variety of drugs, preparing methods to deal with any unexpected toxicity would be valuable. The aim of this study was to evaluate the feasibility of various chelators for reducing and excreting free 225Ac and compare their chemical structures. Nine candidate chelators (D-penicillamine, dimercaprol, Ca-DTPA, Ca-EDTA, CyDTA, GEDTA TTHA, Ca-TTHA, and DO3A) were evaluated in vitro and in vivo. The biodistribution and dosimetry of free 225Ac were examined in mice before an in vivo chelating study. The liver exhibited pronounced 225Ac uptake, with an estimated human absorbed dose of 4.76 SvRBE5/MBq. Aminopolycarboxylate chelators with five and six carboxylic groups, Ca-DTPA and Ca-TTHA, significantly reduced 225Ac retention in the liver (22% and 30%, respectively). Significant 225Ac reductions were observed in the heart and remainder of the body with both Ca-DTPA and Ca-TTHA, and in the lung, kidney, and spleen with Ca-TTHA. In vitro interaction analysis supported the in vivo reduction ability of Ca-DTPA and Ca-TTHA. In conclusion, aminopolycarboxylate chelators with five and six carboxylic groups, Ca-DTPA and Ca-TTHA, were effective for whole-body clearance of free 225Ac. This feasibility study provides useful information for reducing undesirable radiation exposure from free 225Ac.
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Hofmann W, Li WB, Friedland W, Miller BW, Madas B, Bardiès M, Balásházy I. Internal microdosimetry of alpha-emitting radionuclides. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2020; 59:29-62. [PMID: 31863162 PMCID: PMC7012986 DOI: 10.1007/s00411-019-00826-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 12/08/2019] [Indexed: 05/27/2023]
Abstract
At the tissue level, energy deposition in cells is determined by the microdistribution of alpha-emitting radionuclides in relation to sensitive target cells. Furthermore, the highly localized energy deposition of alpha particle tracks and the limited range of alpha particles in tissue produce a highly inhomogeneous energy deposition in traversed cell nuclei. Thus, energy deposition in cell nuclei in a given tissue is characterized by the probability of alpha particle hits and, in the case of a hit, by the energy deposited there. In classical microdosimetry, the randomness of energy deposition in cellular sites is described by a stochastic quantity, the specific energy, which approximates the macroscopic dose for a sufficiently large number of energy deposition events. Typical examples of the alpha-emitting radionuclides in internal microdosimetry are radon progeny and plutonium in the lungs, plutonium and americium in bones, and radium in targeted radionuclide therapy. Several microdosimetric approaches have been proposed to relate specific energy distributions to radiobiological effects, such as hit-related concepts, LET and track length-based models, effect-specific interpretations of specific energy distributions, such as the dual radiation action theory or the hit-size effectiveness function, and finally track structure models. Since microdosimetry characterizes only the initial step of energy deposition, microdosimetric concepts are most successful in exposure situations where biological effects are dominated by energy deposition, but not by subsequently operating biological mechanisms. Indeed, the simulation of the combined action of physical and biological factors may eventually require the application of track structure models at the nanometer scale.
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Affiliation(s)
- Werner Hofmann
- Biological Physics, Department of Chemistry and Physics of Materials, University of Salzburg, Hellbrunner Str. 34, 5020, Salzburg, Austria.
| | - Wei Bo Li
- Institute of Radiation Medicine, Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.
| | - Werner Friedland
- Institute of Radiation Medicine, Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Brian W Miller
- Department of Radiation Oncology, School of Medicine, University of Colorado, Aurora, CO, 80045, USA
- College of Optical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Balázs Madas
- Environmental Physics Department, MTA Centre for Energy Research, Budapest, Hungary
| | - Manuel Bardiès
- Centre de Recherches en Cancérologie de Toulouse, UMR 1037, INSERM Université Paul Sabatier, Toulouse, France
| | - Imre Balásházy
- Environmental Physics Department, MTA Centre for Energy Research, Budapest, Hungary
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Bourgeois D, Burt-Pichat B, Le Goff X, Garrevoet J, Tack P, Falkenberg G, Van Hoorebeke L, Vincze L, Denecke MA, Meyer D, Vidaud C, Boivin G. Micro-distribution of uranium in bone after contamination: new insight into its mechanism of accumulation into bone tissue. Anal Bioanal Chem 2015; 407:6619-25. [PMID: 26084548 DOI: 10.1007/s00216-015-8835-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/03/2015] [Accepted: 06/08/2015] [Indexed: 11/29/2022]
Abstract
After internal contamination, uranium rapidly distributes in the body; up to 20 % of the initial dose is retained in the skeleton, where it remains for years. Several studies suggest that uranium has a deleterious effect on the bone cell system, but little is known regarding the mechanisms leading to accumulation of uranium in bone tissue. We have performed synchrotron radiation-based micro-X-ray fluorescence (SR μ-XRF) studies to assess the initial distribution of uranium within cortical and trabecular bones in contaminated rats' femurs at the micrometer scale. This sensitive technique with high spatial resolution is the only method available that can be successfully applied, given the small amount of uranium in bone tissue. Uranium was found preferentially located in calcifying zones in exposed rats and rapidly accumulates in the endosteal and periosteal area of femoral metaphyses, in calcifying cartilage and in recently formed bone tissue along trabecular bone. Furthermore, specific localized areas with high accumulation of uranium were observed in regions identified as micro-vessels and on bone trabeculae. These observations are of high importance in the study of the accumulation of uranium in bone tissue, as the generally proposed passive chemical sorption on the surface of the inorganic part (apatite) of bone tissue cannot account for these results. Our study opens original perspectives in the field of exogenous metal bio-mineralization.
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Chatelain G, Bourgeois D, Ravaux J, Averseng O, Vidaud C, Meyer D. Incorporation of uranium into a biomimetic apatite: physicochemical and biological aspects. J Biol Inorg Chem 2014; 20:497-507. [PMID: 25534663 DOI: 10.1007/s00775-014-1231-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 12/11/2014] [Indexed: 11/30/2022]
Abstract
Bone is the main target organ for the storage of several toxic metals, including uranium. But the mode of action of uranium on bones remains poorly understood. To better assess the impact of uranium on bone cells, synthetic biomimetic apatites encompassing a controlled amount of uranium were prepared and analyzed. This study revealed the physicochemical impact of uranium on apatite mineralization: the presence of the metal induces a loss of crystallinity and a lower mineralization rate. The prepared samples were then used as substrates for bone cell culture. Osteoblasts were not sensitive to the presence of uranium in the support, whereas previous results showed a deleterious effect of uranium introduced into a cell culture solution. This work should therefore have some original prospects within the context of toxicological studies concerning the effect of metallic cations on bone cell systems.
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Vidaud C, Bourgeois D, Meyer D. Bone as Target Organ for Metals: The Case of f-Elements. Chem Res Toxicol 2012; 25:1161-75. [DOI: 10.1021/tx300064m] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Claude Vidaud
- CEA, IBEB, LEPC, BP 17171, F-30207
Bagnols-sur-Cèze, France
| | - Damien Bourgeois
- ICSM, UMR 5257/CEA/CNRS/UM2/ENSCM,
BP17171, F-30207 Bagnols-sur-Cèze, France
| | - Daniel Meyer
- ICSM, UMR 5257/CEA/CNRS/UM2/ENSCM,
BP17171, F-30207 Bagnols-sur-Cèze, France
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Roeske JC, Aydogan B, Bardies M, Humm JL. Small-Scale Dosimetry: Challenges and Future Directions. Semin Nucl Med 2008; 38:367-83. [DOI: 10.1053/j.semnuclmed.2008.05.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Prado GR, Arruda-Neto JDT, Sarkis JES, Geraldo LP, Müller RML, Garcia F, Bittencourt-Oliveira MC, Guevara MVM, Rodrigues G, Mesa J, Rodrigues TE. Evaluation of uranium incorporation from contaminated areas using teeth as bioindicators--a case study. RADIATION PROTECTION DOSIMETRY 2008; 130:249-252. [PMID: 18192333 DOI: 10.1093/rpd/ncm489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The Southwest region of the Bahia state in Brazil hosts the largest uranium reserve of the country (100 kton in uranium, only), plus the cities of Caetité, Lagoa Real and Igaporã. In this work, aim was at the investigation of uranium burdens on residents of these cities by using teeth as bioindicators, as a contribution for possible radiation protection measures. Thus, a total of 41 human teeth were collected, plus 50 from an allegedly uranium free area (the control region). Concentrations of uranium in teeth from residents of 5- to 87-y old were determined by means of a high-resolution inductively coupled plasma mass spectrometer (ICP-MS). The highest uranium concentration in teeth was measured from samples belonging to residents of Caetité (median equal to 16 ppb). Assuming that the uranium concentrations in teeth and bones are similar within 10-20% (for children and young adults), it concluded that uranium body levels in residents of Caetité are at least one order of magnitude higher than the worldwide average. This finding led to conclude that daily ingestion of uranium, from food and water, is equally high.
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Affiliation(s)
- G R Prado
- Santa Cruz State University, UESC, Ilhéus, BA, Brazil
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Atkinson MJ, Spanner MT, Rosemann M, Linzner U, Müller WA, Gössner W. Intracellular Sequestration of223Ra by the Iron-Storage Protein Ferritin. Radiat Res 2005; 164:230-3. [PMID: 16038594 DOI: 10.1667/rr3410] [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] [Indexed: 11/03/2022]
Abstract
Incorporation of bone-seeking, alpha-particle-emitting, heavy-metal radionuclides dramatically increases the incidence of osteosarcoma in humans and experimental animals. The accumulation of these radionuclides within the mineral phase of the bone matrix is believed to result in local irradiation of only those proliferating cells close to the bone surface. We now present evidence for a more general pathway for the irradiation of target cells, mediated through the sequestration of heavy-metal radionuclides by the intracellular iron-storage protein ferritin. In vitro studies reveal the transfer of radionuclide from a 223Ra-transferrin complex into immunoprecipitable cytosolic ferritin. In vivo studies confirm the co-localization of incorporated 224Ra and cellular iron stores. This pathway would result in the highly localized irradiation of ferritin-containing cells. Since osteoblastic cells express large quantities of a ferritin isoform specialized in long-term metal storage, we suggest that this may represent an unrecognized source of intracellular irradiation by alpha-particle-emitting radionuclides. Such a local concentration within target cells has implications both for cellular dosimetry and for inferences of track length and target cell populations within the skeleton.
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Affiliation(s)
- Michael J Atkinson
- Institute für Pathologie, GSF-Forschungszentrum für Umwelt und Gesundheit, Ingolstädter Landstrasse 1, D85764 Neuherberg, Germany.
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Chinn P, Braslawsky G, White C, Hanna N. Antibody therapy of non-Hodgkin's B-cell lymphoma. Cancer Immunol Immunother 2003; 52:257-80. [PMID: 12700943 PMCID: PMC11034278 DOI: 10.1007/s00262-002-0347-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2002] [Accepted: 10/03/2002] [Indexed: 01/09/2023]
Abstract
Engineering antibodies with reduced immunogenicity and enhanced effector functions, and selecting antigen targets with the appropriate specificity, density, and/or functionality, have contributed to the recent clinical successes in using unconjugated "naked" antibody therapies of B-cell lymphoma (rituximab) and breast carcinoma (Herceptin). The non-overlapping toxicities of naked antibodies and chemotherapy, together with their potential synergy, which is based on unique and complementary mechanisms of action, have contributed to the creation of new standards of care in cancer therapy and management. Clinical trial results supporting these concepts are presented. Furthermore, the exquisite specificity of antibodies renders them ideal vehicles for selective delivery of toxic payloads such as drugs or radionuclides. Although successful in therapy of hematological cancers (Zevalin, Mylotarg), the broader application of these technologies to carcinomas still remains to be proven in clinical testing. Engineering of antibody constructs with optimal blood clearance and tumor-targeting kinetics, and selecting the radionuclide that may deliver sufficient radiation energy to kill the more radio-resistant carcinomas, are discussed. With the advent of genomics and proteomics, new membrane-associated tumor antigens are being discovered and will provide novel targets for future antibody therapy of cancer.
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Affiliation(s)
- Paul Chinn
- IDEC Pharmaceuticals Corporation, 3010 Science Park Road, 92121 San Diego, California USA
| | - Gary Braslawsky
- IDEC Pharmaceuticals Corporation, 3010 Science Park Road, 92121 San Diego, California USA
| | - Christine White
- IDEC Pharmaceuticals Corporation, 3010 Science Park Road, 92121 San Diego, California USA
| | - Nabil Hanna
- IDEC Pharmaceuticals Corporation, 3010 Science Park Road, 92121 San Diego, California USA
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