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Carrasco-Hernandez J, Ramos-Méndez J, Padilla-Rodal E, Avila-Rodriguez MA. Cellular lethal damage of 64Cu incorporated in mammalian genome evaluated with Monte Carlo methods. Front Med (Lausanne) 2023; 10:1253746. [PMID: 37841004 PMCID: PMC10575761 DOI: 10.3389/fmed.2023.1253746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/13/2023] [Indexed: 10/17/2023] Open
Abstract
Purpose Targeted Radionuclide Therapy (TRT) with Auger Emitters (AE) is a technique that allows targeting specific sites on tumor cells using radionuclides. The toxicity of AE is critically dependent on its proximity to the DNA. The aim of this study is to quantify the DNA damage and radiotherapeutic potential of the promising AE radionuclide copper-64 (64Cu) incorporated into the DNA of mammalian cells using Monte Carlo track-structure simulations. Methods A mammalian cell nucleus model with a diameter of 9.3 μm available in TOPAS-nBio was used. The cellular nucleus consisted of double-helix DNA geometrical model of 2.3 nm diameter surrounded by a hydration shell with a thickness of 0.16 nm, organized in 46 chromosomes giving a total of 6.08 giga base-pairs (DNA density of 14.4 Mbp/μm3). The cellular nucleus was irradiated with monoenergetic electrons and radiation emissions from several radionuclides including 111In, 125I, 123I, and 99mTc in addition to 64Cu. For monoenergetic electrons, isotropic point sources randomly distributed within the nucleus were modeled. The radionuclides were incorporated in randomly chosen DNA base pairs at two positions near to the central axis of the double-helix DNA model at (1) 0.25 nm off the central axis and (2) at the periphery of the DNA (1.15 nm off the central axis). For all the radionuclides except for 99mTc, the complete physical decay process was explicitly simulated. For 99mTc only total electron spectrum from published data was used. The DNA Double Strand Breaks (DSB) yield per decay from direct and indirect actions were quantified. Results obtained for monoenergetic electrons and radionuclides 111In, 125I, 123I, and 99mTc were compared with measured and calculated data from the literature for verification purposes. The DSB yields per decay incorporated in DNA for 64Cu are first reported in this work. The therapeutic effect of 64Cu (activity that led 37% cell survival after two cell divisions) was determined in terms of the number of atoms incorporated into the nucleus that would lead to the same DSBs that 100 decays of 125I. Simulations were run until a 2% statistical uncertainty (1 standard deviation) was achieved. Results The behavior of DSBs as a function of the energy for monoenergetic electrons was consistent with published data, the DSBs increased with the energy until it reached a maximum value near 500 eV followed by a continuous decrement. For 64Cu, when incorporated in the genome at evaluated positions (1) and (2), the DSB were 0.171 ± 0.003 and 0.190 ± 0.003 DSB/decay, respectively. The number of initial atoms incorporated into the genome (per cell) for 64Cu that would cause a therapeutic effect was estimated as 3,107 ± 28, that corresponds to an initial activity of 47.1 ± 0.4 × 10-3 Bq. Conclusion Our results showed that TRT with 64Cu has comparable therapeutic effects in cells as that of TRT with radionuclides currently used in clinical practice.
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Affiliation(s)
- Jhonatan Carrasco-Hernandez
- Departamento de Estructura de la Materia, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - José Ramos-Méndez
- Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA, United States
| | - Elizabeth Padilla-Rodal
- Departamento de Estructura de la Materia, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Miguel A. Avila-Rodriguez
- Unidad Radiofarmacia-Ciclotrón, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Koniar H, Miller C, Rahmim A, Schaffer P, Uribe C. A GATE simulation study for dosimetry in cancer cell and micrometastasis from the 225Ac decay chain. EJNMMI Phys 2023; 10:46. [PMID: 37525027 PMCID: PMC10390455 DOI: 10.1186/s40658-023-00564-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 07/24/2023] [Indexed: 08/02/2023] Open
Abstract
BACKGROUND Radiopharmaceutical therapy (RPT) with alpha-emitting radionuclides has shown great promise in treating metastatic cancers. The successive emission of four alpha particles in the 225Ac decay chain leads to highly targeted and effective cancer cell death. Quantifying cellular dosimetry for 225Ac RPT is essential for predicting cell survival and therapeutic success. However, the leading assumption that all 225Ac progeny remain localized at their target sites likely overestimates the absorbed dose to cancer cells. To address limitations in existing semi-analytic approaches, this work evaluates S-values for 225Ac's progeny radionuclides with GATE Monte Carlo simulations. METHODS The cellular geometries considered were an individual cell (10 µm diameter with a nucleus of 8 µm diameter) and a cluster of cells (micrometastasis) with radionuclides localized in four subcellular regions: cell membrane, cytoplasm, nucleus, or whole cell. The absorbed dose to the cell nucleus was scored, and self- and cross-dose S-values were derived. We also evaluated the total absorbed dose with various degrees of radiopharmaceutical internalization and retention of the progeny radionuclides 221Fr (t1/2 = 4.80 m) and 213Bi (t1/2 = 45.6 m). RESULTS For the cumulative 225Ac decay chain, our self- and cross-dose nuclear S-values were both in good agreement with S-values published by MIRDcell, with per cent differences ranging from - 2.7 to - 8.7% for the various radionuclide source locations. Source location had greater effects on self-dose S-values than the intercellular cross-dose S-values. Cumulative 225Ac decay chain self-dose S-values increased from 0.167 to 0.364 GyBq-1 s-1 with radionuclide internalization from the cell surface into the cell. When progeny migration from the target site was modelled, the cumulative self-dose S-values to the cell nucleus decreased by up to 71% and 21% for 221Fr and 213Bi retention, respectively. CONCLUSIONS Our GATE Monte Carlo simulations resulted in cellular S-values in agreement with existing MIRD S-values for the alpha-emitting radionuclides in the 225Ac decay chain. To obtain accurate absorbed dose estimates in 225Ac studies, accurate understanding of daughter migration is critical for optimized injected activities. Future work will investigate other novel preclinical alpha-emitting radionuclides to evaluate therapeutic potency and explore realistic cellular geometries corresponding to targeted cancer cell lines.
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Affiliation(s)
- Helena Koniar
- Life Sciences Division, TRIUMF, Vancouver, BC, Canada.
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.
| | - Cassandra Miller
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, Canada
| | - Arman Rahmim
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Paul Schaffer
- Life Sciences Division, TRIUMF, Vancouver, BC, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Carlos Uribe
- Department of Radiology, University of British Columbia, Vancouver, BC, Canada
- Functional Imaging, BC Cancer, Vancouver, BC, Canada
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Estimation of biological effect of Cu-64 radiopharmaceuticals with Geant4-DNA simulation. Sci Rep 2022; 12:8957. [PMID: 35624130 PMCID: PMC9142517 DOI: 10.1038/s41598-022-13096-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 05/05/2022] [Indexed: 11/24/2022] Open
Abstract
The aim of this work is to estimate the biological effect of targeted radionuclide therapy using Cu-64, which is a well-known Auger electron emitter. To do so, we evaluate the absorbed dose of emitted particles from Cu-64 using the Geant4-DNA Monte Carlo simulation toolkit. The contribution of beta particles to the absorbed dose is higher than that of Auger electrons. The simulation result agrees with experimental ones evaluated using coumarin-3-carboxylic acid chemical dosimeter. The simulation result is also in good agreement with previous ones obtained using fluorescent nuclear track detector. From the results of present simulation (i.e., absorbed dose estimation) and previous biological experiments using two cell lines (i.e., evaluation of survival curves), we have estimated the relative biological effectiveness (RBE) of Cu-64 emitted particles on CHO wild-type cells and xrs5 cells. The RBE of xrs5 cells exposed to Cu-64 is almost equivalent to that with gamma rays and protons and C ions. This result indicates that the radiosensitivity of xrs5 cells is independent of LET. In comparison to this, the RBE on CHO wild-type cells exposed to Cu-64 is significantly higher than gamma rays and almost equivalent to that irradiated with C ions with a linear energy transfer of 70 keV/μm.
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Jalilian AR, Osso JA, Vera-Araujo J, Kumar V, Harris MJ, Gutfilen B, Guérin B, Li H, Zhuravlev F, Chakravarty R, Alirezapour B, Ávila-Rodríguez MA, Khan IU, Aljammaz I, Assaad T, Luurtsema G, Smith J, Duatti A. IAEA contribution to the development of 64Cu radiopharmaceuticals for theranostic applications. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF RADIOPHARMACEUTICAL CHEMISTRY AND BIOLOGY 2020; 64:338-345. [PMID: 33026211 DOI: 10.23736/s1824-4785.20.03302-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Copper-64 is a very attractive radioisotope with unique nuclear properties that allow using it as both a diagnostic and therapeutic agent, thus providing an almost ideal example of a theranostic radionuclide. A characteristic of Cu-64 stems from the intrinsic biological nature of copper ions that play a fundamental role in a large number of cellular processes. Cu-64 is a radionuclide that reflects the natural biochemical pathways of Cu-64 ions, therefore, can be exploited for the detection and therapy of certain malignancies and metabolic diseases. Beside these applications of Cu-64 ions, this radionuclide can be also used for radiolabelling bifunctional chelators carrying a variety of pharmacophores for targeting different biological substrates. These include peptide-based substrates and immunoconjugates as well as small-molecule bioactive moieties. Fueled by the growing interest of Member States (MS) belonging to the International Atomic Energy Agency (IAEA) community, a dedicated Coordinated Research Project (CRP) was initiated in 2016, which recruited thirteen participating MS from four continents. Research activities and collaborations between the participating countries allowed for collection of an impressive series of results, particularly on the production, preclinical evaluation and, in a few cases, clinical evaluation of various 64Cu-radiopharmaceuticals that may have potential impact on future development of the field. Since this CRP was finalized at the beginning of 2020, this short review summarizes outcomes, outputs and results of this project with the purpose to propagate to other MS and to the whole scientific community, some of the most recent achievements on this novel class of theranostic 64Cu-pharmaceuticals.
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Affiliation(s)
- Amir R Jalilian
- Department of Nuclear Sciences and Applications, International Atomic Energy Agency (IAEA), Vienna International Center, Vienna, Austria -
| | - Joao A Osso
- Department of Nuclear Sciences and Applications, International Atomic Energy Agency (IAEA), Vienna International Center, Vienna, Austria
| | - Julia Vera-Araujo
- Department of Nuclear Sciences and Applications, International Atomic Energy Agency (IAEA), Vienna International Center, Vienna, Austria
| | - Vijay Kumar
- Westmead Hospital, Westmead, Sydney, Australia
| | | | - Bianca Gutfilen
- Department of Radiology, Federal University of Rio de Janeiro, Laboratório de Marcação de Células e Moléculas (LMCM), Rio de Janeiro, Brazil
| | - Brigitte Guérin
- Department of Nuclear Medicine and Radiobiology, Centre de Recherche du CHUS (CRCHUS), Centre d'Excellence en Imagerie Médicale (CIMUS), University of Sherbrooke, Sherbrooke, Canada
| | - Hongyu Li
- China Isotope and Radiation Corporation, Beijing, China
| | - Fedor Zhuravlev
- Hevesy Laboratory, Technical University of Denmark (DTU HEALTH TECH), Roskilde, Denmark
| | - Rubel Chakravarty
- Division of Radiopharmaceuticals, Bhabha Atomic Research Center, Mumbai, India
| | - Behrouz Alirezapour
- Radiation Applications Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
| | - Miguel A Ávila-Rodríguez
- Unit of Cyclotron and Radiopharmaceuticals, Division of Investigation, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
| | - Irfan U Khan
- Division of Cyclotron and Allied Radiopharmaceuticals, Institute of Nuclear Medicine and Oncology (INMOL), Lahore, Pakistan
| | - Ibrahim Aljammaz
- Department of Cyclotron and Radiopharmaceuticals, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Thaer Assaad
- Department of Radioisotope, Atomic Energy Commission of Syria (AECS), Damascus, Syria
| | - Gert Luurtsema
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen (UMCG), Groningen, the Netherlands
| | - Jeff Smith
- MU School of Medicine, University of Missouri, Columbia, MO, USA
| | - Adriano Duatti
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Ferrara, Italy
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