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Hoffman SLV, Mixdorf JC, Kwon O, Johnson TR, Makvandi M, Lee H, Aluicio-Sarduy E, Barnhart TE, Jeffery JJ, Patankar MS, Engle JW, Bednarz BP, Ellison PA. Preclinical studies of a PARP targeted, Meitner-Auger emitting, theranostic radiopharmaceutical for metastatic ovarian cancer. Nucl Med Biol 2023; 122-123:108368. [PMID: 37490805 PMCID: PMC10529069 DOI: 10.1016/j.nucmedbio.2023.108368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/11/2023] [Accepted: 07/17/2023] [Indexed: 07/27/2023]
Abstract
Advanced ovarian cancer currently has few therapeutic options. Poly(ADP-ribose) polymerase (PARP) inhibitors bind to nuclear PARP and trap the protein-inhibitor complex to DNA. This work investigates a theranostic PARP inhibitor for targeted radiopharmaceutical therapy of ovarian cancer in vitro and PET imaging of healthy mice in vivo. METHODS [77Br]RD1 was synthesized and assessed for pharmacokinetics and cytotoxicity in human and murine ovarian cancer cell lines. [76Br]RD1 biodistribution and organ uptake in healthy mice were quantified through longitudinal PET/CT imaging and ex vivo radioactivity measurements. Organ-level dosimetry following [76/77Br]RD1 administration was calculated using RAPID, an in-house platform for absorbed dose in mice, and OLINDA for equivalent and effective dose in human. RESULTS The maximum specific binding (Bmax), equilibrium dissociation constant (Kd), and nonspecific binding slope (NS) were calculated for each cell line. These values were used to calculate the cell specific activity uptake for cell viability studies. The half maximal effective concentration (EC50) was measured as 0.17 (95 % CI: 0.13-0.24) nM and 0.46 (0.13-0.24) nM for PARP(+) and PARP(-) expressing cell lines, respectively. The EC50 was 0.27 (0.21-0.36) nM and 0.30 (0.22-0.41) nM for BRCA1(-) and BRCA1(+) expressing cell lines, respectively. When measuring the EC50 as a function of cellular activity uptake and nuclear dose, the EC50 ranges from 0.020 to 0.039 Bq/cell and 3.3-9.2 Gy, respectively. Excretion through the hepatobiliary and renal pathways were observed in mice, with liver uptake of 2.3 ± 0.4 %ID/g after 48 h, contributing to estimated absorbed dose values in mice of 19.3 ± 0.3 mGy/MBq and 290 ± 10 mGy/MBq for [77Br]RD1 and [76Br]RD1, respectively. CONCLUSION [77Br]RD1 cytotoxicity was dependent on PARP expression and independent of BRCA1 status. The in vitro results suggest that [77Br]RD1 cytotoxicity is driven by the targeted Meitner-Auger electron (MAe) radiotherapeutic effect of the agent. Further studies investigating the theranostic potential, organ dose, and tumor uptake of [76/77Br]RD1 are warranted.
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Affiliation(s)
- S L V Hoffman
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - J C Mixdorf
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - O Kwon
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - T R Johnson
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - M Makvandi
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - H Lee
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - E Aluicio-Sarduy
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - T E Barnhart
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - J J Jeffery
- University of Wisconsin Carbone Cancer Center, Madison, WI, USA
| | - M S Patankar
- Department of Obstetrics and Gynecology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - J W Engle
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA; Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - B P Bednarz
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - P A Ellison
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
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Yang YM, Geurts M, Smilowitz JB, Sterpin E, Bednarz BP. Monte Carlo simulations of patient dose perturbations in rotational-type radiotherapy due to a transverse magnetic field: a tomotherapy investigation. Med Phys 2015; 42:715-25. [PMID: 25652485 DOI: 10.1118/1.4905168] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Several groups are exploring the integration of magnetic resonance (MR) image guidance with radiotherapy to reduce tumor position uncertainty during photon radiotherapy. The therapeutic gain from reducing tumor position uncertainty using intrafraction MR imaging during radiotherapy could be partially offset if the negative effects of magnetic field-induced dose perturbations are not appreciated or accounted for. The authors hypothesize that a more rotationally symmetric modality such as helical tomotherapy will permit a systematic mediation of these dose perturbations. This investigation offers a unique look at the dose perturbations due to homogeneous transverse magnetic field during the delivery of Tomotherapy(®) Treatment System plans under varying degrees of rotational beamlet symmetry. METHODS The authors accurately reproduced treatment plan beamlet and patient configurations using the Monte Carlo code geant4. This code has a thoroughly benchmarked electromagnetic particle transport physics package well-suited for the radiotherapy energy regime. The three approved clinical treatment plans for this study were for a prostate, head and neck, and lung treatment. The dose heterogeneity index metric was used to quantify the effect of the dose perturbations to the target volumes. RESULTS The authors demonstrate the ability to reproduce the clinical dose-volume histograms (DVH) to within 4% dose agreement at each DVH point for the target volumes and most planning structures, and therefore, are able to confidently examine the effects of transverse magnetic fields on the plans. The authors investigated field strengths of 0.35, 0.7, 1, 1.5, and 3 T. Changes to the dose heterogeneity index of 0.1% were seen in the prostate and head and neck case, reflecting negligible dose perturbations to the target volumes, a change from 5.5% to 20.1% was observed with the lung case. CONCLUSIONS This study demonstrated that the effect of external magnetic fields can be mitigated by exploiting a more rotationally symmetric treatment modality.
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Affiliation(s)
- Y M Yang
- Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin 53703
| | - M Geurts
- Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin 53703
| | - J B Smilowitz
- Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin 53703
| | - E Sterpin
- Molecular Imaging, Radiotherapy and Oncology, Université catholique de Louvain, Brussels, Belgium 1348
| | - B P Bednarz
- Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin 53703
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Ludwig KD, Bouchlaka MN, Gordon JW, Bednarz BP, Capitini CM, Fain SB. MO-A-BRD-03: Quantifying 19F-Labeled Human Natural Killer Cell-Trafficking with MRI. Med Phys 2014. [DOI: 10.1118/1.4889106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Fowler TL, Martin JA, Shepard AJ, Bailey AM, Nickel KP, Kimple RJ, Bednarz BP. WE-E-BRE-03: Biological Validation of a Novel High-Throughput Irradiator for Predictive Radiation Sensitivity Bioassays. Med Phys 2014. [DOI: 10.1118/1.4889432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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