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Julian W, Sergeeva O, Cao W, Wu C, Erokwu B, Flask C, Zhang L, Wang X, Basilion J, Yang S, Lee Z. Searching for Protein Off-Targets of Prostate-Specific Membrane Antigen-Targeting Radioligands in the Salivary Glands. Cancer Biother Radiopharm 2024. [PMID: 39268679 DOI: 10.1089/cbr.2024.0066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/17/2024] Open
Abstract
Background: Prostate specific membrane antigen (PSMA)-targeted radioligand therapies represent a highly effective treatment for metastatic prostate cancer. However, high and sustain uptake of PSMA-ligands in the salivary glands led to dose limiting dry mouth (xerostomia), especially with α-emitters. The expression of PSMA and histologic analysis couldn't directly explain the toxicity, suggesting a potential off-target mediator for uptake. In this study, we set out to search for possible off-target non-PSMA protein(s) in the salivary glands. Methods: A machine-learning based quantitative structure activity relationship (QSAR) model was built for seeking the possible off-target(s). The resulting target candidates from the model prediction were subjected to further analysis for salivary protein expression and structural homology at key regions required for PSMA-ligand binding. Furthermore, cellular binding assays were performed utilizing multiple cell lines with high expression of the candidate proteins and low expression of PSMA. Finally, PSMA knockout (PSMA-/-) mice were scanned by small animal PET/MR using [68Ga]Ga-PSMA-11 for in-vivo validation. Results: The screening of the trained QSAR model did not yield a solid off-target protein, which was corroborated in part by cellular binding assays. Imaging using PSMA-/- mice further demonstrated markedly reduced PSMA-radioligand uptake in the salivary glands. Conclusion: Uptake of the PSMA-targeted radioligands in the salivary glands remains primarily PSMA-mediated. Further investigations are needed to illustrate a seemingly different process of uptake and retention in the salivary glands than that in prostate cancer.
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Affiliation(s)
- William Julian
- Radiology Department, Case Western Reserve University, Cleveland, Ohio, USA
| | - Olga Sergeeva
- Radiology Department, Case Western Reserve University, Cleveland, Ohio, USA
| | - Wei Cao
- Radiology Department, Case Western Reserve University, Cleveland, Ohio, USA
| | - Chunying Wu
- Radiology Department, Case Western Reserve University, Cleveland, Ohio, USA
| | - Bernadette Erokwu
- Radiology Department, Case Western Reserve University, Cleveland, Ohio, USA
| | - Chris Flask
- Radiology Department, Case Western Reserve University, Cleveland, Ohio, USA
| | - Lifang Zhang
- Radiology Department, Case Western Reserve University, Cleveland, Ohio, USA
| | - Xinning Wang
- Radiology Department, Case Western Reserve University, Cleveland, Ohio, USA
- Biomedical Engineering Department, Case Western Reserve University, Cleveland, Ohio, USA
| | - James Basilion
- Radiology Department, Case Western Reserve University, Cleveland, Ohio, USA
- Biomedical Engineering Department, Case Western Reserve University, Cleveland, Ohio, USA
| | - Sichun Yang
- Nutrition Department, Case Western Reserve University, Cleveland, Ohio, USA
| | - Zhenghong Lee
- Radiology Department, Case Western Reserve University, Cleveland, Ohio, USA
- Biomedical Engineering Department, Case Western Reserve University, Cleveland, Ohio, USA
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Lucaroni L, Oehler S, Georgiev T, Müller M, Bocci M, De Luca R, Favalli N, Neri D, Cazzamalli S, Prati L. DNA-encoded chemical libraries enable the discovery of potent PSMA-ligands with substantially reduced affinity towards the GCPIII anti-target. Chem Sci 2024; 15:6789-6799. [PMID: 38725500 PMCID: PMC11077555 DOI: 10.1039/d3sc06668a] [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: 12/12/2023] [Accepted: 03/17/2024] [Indexed: 05/12/2024] Open
Abstract
Prostate-specific membrane antigen (PSMA) is a tumor-associated protein that has been successfully targeted with small organic ligands and monoclonal antibodies. Pluvicto™ is a PSMA-targeted radioligand therapeutic (RLT) recently approved by the FDA for the treatment of metastatic castration-resistant prostate cancer (2022 FDA marketing authorization). Although a large Phase III clinical trial (VISION trial) demonstrated clinical benefits in patients treated with Pluvicto™, the therapeutic window of the drug is narrowed by its undesired accumulation in healthy organs. Glutamate carboxypeptidase III (GCPIII), an enzyme sharing 70% identity with PSMA, may be responsible for the off-target accumulation of PSMA-RLTs in salivary glands and kidneys. In this work, we designed and synthesized affinity and selectivity maturation DNA-encoded chemical libraries (ASM-DELs) comprising 18'284'658 compounds that were screened in parallel against PSMA and GCPIII with the aim to identify potent and selective PSMA ligands for tumor-targeting applications. Compound A70-B104 was isolated as the most potent and selective ligand (KD of 900 pM for PSMA, KD of 40 nM for GCPIII). 177Lu-A70-B104-DOTA, a radiolabeled derivative of compound A70-B104, presented selective accumulation in PSMA-positive cancer lesions (i.e., 7.4% ID g-1, 2 hour time point) after systemic administration in tumor-bearing mice. The results of autoradiography experiments showed that 177Lu-A70-B104-DOTA selectively binds to PSMA-positive cancer tissues, while negligible binding on human salivary glands was observed.
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Affiliation(s)
- Laura Lucaroni
- Philochem AG, R&D Department CH-8112 Otelfingen Switzerland +41 43 544 88 19
| | - Sebastian Oehler
- Philochem AG, R&D Department CH-8112 Otelfingen Switzerland +41 43 544 88 19
| | - Tony Georgiev
- Philochem AG, R&D Department CH-8112 Otelfingen Switzerland +41 43 544 88 19
| | - Marco Müller
- Philochem AG, R&D Department CH-8112 Otelfingen Switzerland +41 43 544 88 19
| | - Matilde Bocci
- Philochem AG, R&D Department CH-8112 Otelfingen Switzerland +41 43 544 88 19
| | - Roberto De Luca
- Philochem AG, R&D Department CH-8112 Otelfingen Switzerland +41 43 544 88 19
| | - Nicholas Favalli
- Philochem AG, R&D Department CH-8112 Otelfingen Switzerland +41 43 544 88 19
| | - Dario Neri
- Philochem AG, R&D Department CH-8112 Otelfingen Switzerland +41 43 544 88 19
- Swiss Federal Institute of Technology, Department of Chemistry and Applied Biosciences CH-8093 Zurich Switzerland
- Philogen S.p.A. 53100 Siena Italy +39 0577 178 16 59
| | - Samuele Cazzamalli
- Philochem AG, R&D Department CH-8112 Otelfingen Switzerland +41 43 544 88 19
| | - Luca Prati
- Philogen S.p.A. 53100 Siena Italy +39 0577 178 16 59
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Böhnke N, Indrevoll B, Hammer S, Papple A, Kristian A, Briem H, Celik A, Mumberg D, Cuthbertson A, Zitzmann-Kolbe S. Mono- and multimeric PSMA-targeting small molecule-thorium-227 conjugates for optimized efficacy and biodistribution in preclinical models. Eur J Nucl Med Mol Imaging 2024; 51:669-680. [PMID: 37882848 PMCID: PMC10796422 DOI: 10.1007/s00259-023-06474-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 10/15/2023] [Indexed: 10/27/2023]
Abstract
PURPOSE PSMA (prostate-specific membrane antigen) is highly expressed on prostate cancer (PrCa) cells and extensively used as a homing target for PrCa treatment. Most prominently, PSMA-targeting conjugate PSMA-617, carrying a DOTA chelator and labeled with therapeutic radionuclides like beta-emitting lutetium-177 or alpha-emitting actinium-225, has shown clinical activity in PrCa patients. We sought to develop PSMA-targeting small molecule (SMOL) conjugates that show high uptake in PSMA-expressing tumors and fast clearance, and can easily be labeled with the alpha emitter thorium-227 (half-life 18.7 days). METHODS A novel linker motif with improved competition against 3H-PSMA-617 on PSMA-expressing LNCaP cells was identified. A 2,3-hydroxypyridinone chelator modified with carboxyl groups (carboxy-HOPO) with increased hydrophilicity and robust labeling with thorium-227 was developed and allowed the synthesis of mono-, di-, tri-, and tetrameric conjugates. The resulting monomeric and multimeric PSMA SMOL-TTCs (targeted thorium conjugate) were evaluated for cellular binding, internalization, and antiproliferative activity. The in vivo antitumor efficacy of the PSMA SMOL-TTCs was determined in ST1273 and KUCaP-1 PrCa models in mice, and their biodistribution was assessed in cynomolgus monkeys, minipigs, and mice. RESULTS The monomeric and multimeric PSMA SMOL conjugates were readily labeled with thorium-227 at room temperature and possessed high stability and good binding, internalization, and antiproliferative activity in vitro. In vivo, the monomeric, dimeric, and trimeric PSMA SMOL-TTCs showed fast clearance, potent antitumor efficacy, and high uptake and retention in prostate tumors in mice. No major uptake or retention in other organs was observed beyond kidneys. Low uptake of free thorium-227 into bone confirmed high complex stability in vivo. Salivary gland uptake remained inconclusive as mini pigs were devalidated as a relevant model and imaging controls failed in cynomolgus monkeys. CONCLUSION Monomeric and multimeric PSMA SMOL-TTCs show high tumor uptake and fast clearance in preclinical models and warrant further therapeutic exploration.
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Affiliation(s)
- Niels Böhnke
- Pharmaceuticals, Bayer AG, 13342, Berlin, Germany
| | | | | | | | | | - Hans Briem
- Pharmaceuticals, Bayer AG, 13342, Berlin, Germany
| | - Arif Celik
- Pharmaceuticals, Bayer AG, 13342, Berlin, Germany
| | - Dominik Mumberg
- Pharmaceuticals, Bayer AG, 13342, Berlin, Germany
- Adcendo ApS, Copenhagen, Denmark
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Huang SS, DiFilippo FP, Lindner DJ, Heston WD. A novel PSMA-targeting tracer with highly negatively charged linker demonstrates decreased salivary gland uptake in mice compared to [ 68Ga]Ga-PSMA-11. EJNMMI Radiopharm Chem 2024; 9:7. [PMID: 38289450 PMCID: PMC10828251 DOI: 10.1186/s41181-024-00237-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/18/2024] [Indexed: 02/02/2024] Open
Abstract
BACKGROUND The current generation of radiolabeled PSMA-targeting therapeutic agents is limited by prominent salivary gland binding, which results in dose-limiting xerostomia from radiation exposure. JB-1498 is a urea-based small molecule with a highly negatively charged linker targeting prostate specific membrane antigen (PSMA). Prior work on a similar tracer with the same negatively charged linker demonstrated low normal organ/soft tissue background uptake compared to [68Ga]Ga-PSMA-11. The purpose of this study was to investigate if [68Ga]Ga-JB-1498 had reduced salivary gland uptake in mice compared to [68Ga]Ga-PSMA-11. RESULTS JB-1498 demonstrated high affinity for PSMA binding and tumor uptake in a murine tumor model. In an initial biodistribution study with low molar activity, [68Ga]Ga-JB-1498 demonstrated salivary gland uptake of 0.13 ± 0.01%ID/g. In a second biodistribution study in non-tumor-bearing mice with high molar activity, [68Ga]Ga-JB1498 demonstrated salivary gland uptake of 0.39 ± 0.24% ID/g and kidney activity of 10.12 ± 1.73% ID/g at one hour post IV injection. This salivary gland uptake is significantly less than the published uptake of [68Ga]Ga-PSMA-11. Micro-PET visually confirmed the findings of the biodistribution studies. Dynamic micro-PET imaging demonstrated gradually decreasing [68Ga]Ga-JB1498 activity in salivary glands and kidneys, compared to gradually increasing [68Ga]Ga-PSMA-11 activity in these two organs during the first hour. CONCLUSION Biodistribution and micro-PET imaging of [68Ga]Ga-JB-1498 demonstrate significantly decreased salivary gland uptake and different pharmacokinetic behavior in kidneys and salivary glands in mice compared to [68Ga]Ga-PSMA-11. Our findings suggest that constructing a PSMA-targeting molecule with a highly negatively charged linker is a promising strategy to reduce salivary gland uptake of GCP-II/PSMA ligands in theranostic applications.
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Affiliation(s)
- Steve S Huang
- Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA.
- Department of Radiology, Mayo Clinic, 13400 E. Shea Blvd., Scottsdale, AZ, 85259, USA.
| | | | | | - Warren D Heston
- Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
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Baun C, Dam JH, Hildebrandt MG, Ewald JD, Kristensen BW, Gammelsrød VS, Olsen BB, Thisgaard H. Preclinical evaluation of [ 58mCo]Co-DOTA-PSMA-617 for Auger electron therapy of prostate cancer. Sci Rep 2023; 13:18837. [PMID: 37914790 PMCID: PMC10620164 DOI: 10.1038/s41598-023-43429-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 09/23/2023] [Indexed: 11/03/2023] Open
Abstract
Prostate-specific membrane antigen (PSMA), highly expressed in prostate cancer, is a promising target for radionuclide therapy. Auger electron-emitting radionuclides are well suited for targeted radionuclide therapy if they can be delivered close to the DNA of the targeted cells. This preclinical study evaluated the theranostic pair [55/58mCo]Co-DOTA-PSMA-617 for PET imaging and Auger electron therapy of prostate cancer. [58mCo]Co-DOTA-PSMA-617 was successfully prepared with > 99% radiochemical yield and purity. In vitro, uptake and subcellular distribution assays in PSMA-positive prostate cancer cells showed PSMA-specific uptake with high cell-associated activity in the nucleus. Incubation with [58mCo]Co-DOTA-PSMA-617 reduced cell viability and clonogenic survival in a significant dose-dependent manner (p < 0.05). Biodistribution of xenografted mice showed high specific tumor uptake of the cobalt-labeled PSMA ligand for all time points with rapid clearance from normal tissues, which PET imaging confirmed. In vivo, therapy with [58mCo]Co-DOTA-PSMA-617 in tumor-bearing mice demonstrated significantly increased median survival for treated mice compared to control animals (p = 0.0014). In conclusion, [55/58mCo]Co-DOTA-PSMA-617 displayed excellent in vitro and in vivo properties, offering significant survival benefits in mice with no observed toxicities.
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Affiliation(s)
- Christina Baun
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense C, Denmark
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Center for Personalized Response Monitoring in Oncology (PREMIO), Odense University Hospital, Odense, Denmark
| | - Johan Hygum Dam
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense C, Denmark
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Malene Grubbe Hildebrandt
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense C, Denmark
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Center for Personalized Response Monitoring in Oncology (PREMIO), Odense University Hospital, Odense, Denmark
- Centre for Innovative Medical Technology, Odense University Hospital, Odense, Denmark
| | - Jesper Dupont Ewald
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Pathology, Odense University Hospital, Odense, Denmark
| | - Bjarne Winther Kristensen
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Pathology, Odense University Hospital, Odense, Denmark
| | - Vigga Sand Gammelsrød
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense C, Denmark
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Birgitte Brinkmann Olsen
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense C, Denmark
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Surgical Pathology, Zealand University Hospital, Roskilde, Denmark
| | - Helge Thisgaard
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense C, Denmark.
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark.
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Huang SS, DiFilippo F, Lindner D, Heston WDW. Intriguing information from recent letter and article regarding unwanted targeting of salivary glands by PSMA ligands. Eur J Nucl Med Mol Imaging 2023; 50:2950-2951. [PMID: 37395801 DOI: 10.1007/s00259-023-06325-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 06/24/2023] [Indexed: 07/04/2023]
Affiliation(s)
- Steve S Huang
- Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA.
- Department of Radiology, Mayo Clinic, 13400 E. Shea Blvd., Scottsdale, AZ, 85259, USA.
| | - Frank DiFilippo
- Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Daniel Lindner
- Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
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Sublingual Atropine Administration as a Tool to Decrease Salivary Glands' PSMA-Ligand Uptake: A Preclinical Proof of Concept Study Using [ 68Ga]Ga-PSMA-11. Pharmaceutics 2022; 14:pharmaceutics14061276. [PMID: 35745848 PMCID: PMC9230580 DOI: 10.3390/pharmaceutics14061276] [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: 04/25/2022] [Revised: 06/06/2022] [Accepted: 06/13/2022] [Indexed: 02/04/2023] Open
Abstract
Prostate Specific Membrane Antigen (PSMA)-directed radionuclide therapy has gained an important role in the management of advanced castration-resistant prostate cancer. Although extremely promising, the prolongation in survival and amelioration of disease-related symptoms must be balanced against the direct toxicities of the treatment. Xerostomia is amongst the most common and debilitating of these, particularly when using an alpha emitter. It is therefore of main importance to develop new preventive strategies. This preclinical study has evaluated the effect of α-adrenergic and anticholinergic drugs on [99mTc]TcO4− Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) and [68Ga]Ga-PSMA-11 Positron Emission Tomography (PET/CT). Methods: The effects of phenylephrine, scopolamine, atropine, and ipratropium on salivary glands uptake were evaluated in non-tumor-bearing mice by [99mTc]TcO4− microSPECT/CT. The most efficient identified strategy was evaluated in non-tumor-bearing and xenografted mice by [68Ga]Ga-PSMA-11 PET/CT. Results: Scopolamine and atropine showed a significant decrease in the parotid glands’ uptake on SPECT/CT whereas phenylephrine and ipratropium failed. Atropine premedication (sublingual route), which was the most effective strategy, also showed a drastic decrease of [68Ga]Ga-PSMA-11 salivary glands’ uptake in both non-tumor-bearing mice (−51.6% for the parotids, p < 0.0001) and human prostate adenocarcinoma xenografted mice (−26.8% for the parotids, p < 0.0001). Conclusion: Premedication with a local administration of atropine could represent a simple, safe, and efficient approach for reducing salivary glands’ uptake.
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Basuli F, Phelps TE, Zhang X, Woodroofe CC, Roy J, Choyke PL, Swenson RE, Jagoda EM. Fluorine-18 Labeled Urea-Based Ligands Targeting Prostate-Specific Membrane Antigen (PSMA) with Increased Tumor and Decreased Renal Uptake. Pharmaceuticals (Basel) 2022; 15:597. [PMID: 35631423 PMCID: PMC9144807 DOI: 10.3390/ph15050597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/07/2022] [Accepted: 05/11/2022] [Indexed: 12/22/2022] Open
Abstract
High expression of prostate-specific membrane antigen (PSMA) in prostate cancers prompted the development of the PSMA-targeted PET-imaging agent [18F]DCFPyL, which was recently approved by the FDA. Fluorine-18-labeled Lys-Urea-Glu-based oxime derivatives of [18F]DCFPyL were prepared for the comparison of their in vitro and in vivo properties to potentially improve kidney clearance and tumor targeting. The oxime radiotracers were produced by condensation of an aminooxy functionalized PSMA-inhibitor Lys-Urea-Glu scaffold with fluorine-18-labeled aldehydes. The radiochemical yields were between 15-42% (decay uncorrected) in 50-60 min. In vitro saturation and competition binding assays with human prostate cancer cells transfected with PSMA, PC3(+), indicated similar high nM binding affinities to PSMA for all radiotracers. In vivo biodistribution studies with positive control PC3(+) tumor xenografts showed that the kidneys had the highest uptake followed by tumors at 60 min. The PC3(+) tumor uptake was blocked with non-radioactive DCFPyL, and PC3(-) tumor xenograft (negative control) tumor uptake was negligible indicating that PSMA targeting was preserved. The most lipophilic tracer, [18F]2a, displayed comparable tumor-targeting to [18F]DCFPyL and a desirable alteration in pharmacokinetics and metabolism, resulting in significantly lower kidney uptake with a shift towards hepatobiliary clearance and increased liver uptake.
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Affiliation(s)
- Falguni Basuli
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA; (X.Z.); (C.C.W.); (R.E.S.)
| | - Tim E. Phelps
- Molecular Imaging Branch, National Cancer Institute, Bethesda, MD 20892, USA; (T.E.P.); (J.R.); (P.L.C.); (E.M.J.)
| | - Xiang Zhang
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA; (X.Z.); (C.C.W.); (R.E.S.)
| | - Carolyn C. Woodroofe
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA; (X.Z.); (C.C.W.); (R.E.S.)
| | - Jyoti Roy
- Molecular Imaging Branch, National Cancer Institute, Bethesda, MD 20892, USA; (T.E.P.); (J.R.); (P.L.C.); (E.M.J.)
| | - Peter L. Choyke
- Molecular Imaging Branch, National Cancer Institute, Bethesda, MD 20892, USA; (T.E.P.); (J.R.); (P.L.C.); (E.M.J.)
| | - Rolf E. Swenson
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA; (X.Z.); (C.C.W.); (R.E.S.)
| | - Elaine M. Jagoda
- Molecular Imaging Branch, National Cancer Institute, Bethesda, MD 20892, USA; (T.E.P.); (J.R.); (P.L.C.); (E.M.J.)
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Ong JS, Hofman MS. PET imaging of prostate cancer. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00111-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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10
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Impact of the molar activity and PSMA expression level on [ 18F]AlF-PSMA-11 uptake in prostate cancer. Sci Rep 2021; 11:22623. [PMID: 34799653 PMCID: PMC8604919 DOI: 10.1038/s41598-021-02104-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 11/10/2021] [Indexed: 11/10/2022] Open
Abstract
This two-part preclinical study aims to evaluate prostate specific membrane antigen (PSMA) as a valuable target for expression-based imaging applications and to determine changes in target binding in function of varying apparent molar activities (MAapp) of [18F]AlF-PSMA-11. For the evaluation of PSMA expression levels, male NOD/SCID mice bearing prostate cancer (PCa) xenografts of C4-2 (PSMA+++), 22Rv1 (PSMA+) and PC-3 (PSMA−) were administered [18F]AlF-PSMA-11 with a medium MAapp (20.24 ± 3.22 MBq/nmol). SUVmean and SUVmax values were respectively 3.22 and 3.17 times higher for the high versus low PSMA expressing tumors (p < 0.0001). To evaluate the effect of varying MAapp, C4-2 and 22Rv1 xenograft bearing mice underwent additional [18F]AlF-PSMA-11 imaging with a high (211.2 ± 38.9 MBq/nmol) and/or low MAapp (1.92 ± 0.27 MBq/nmol). SUV values showed a significantly increasing trend with higher MAapp. Significant changes were found for SUVmean and SUVmax between the high versus low MAapp and medium versus low MAapp (both p < 0.05), but not between the high versus medium MAapp (p = 0.055 and 0.25, respectively). The effect of varying MAapp was more pronounced in low expressing tumors and PSMA expressing tissues (e.g. salivary glands and kidneys). Overall, administration of a high MAapp increases the detection of low expression tumors while also increasing uptake in PSMA expressing tissues, possibly leading to false positive findings. In radioligand therapy, a medium MAapp could reduce radiation exposure to dose-limiting organs with only limited effect on radionuclide accumulation in the tumor.
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Roy J, White ME, Basuli F, Opina ACL, Wong K, Riba M, Ton AT, Zhang X, Jansson KH, Edmondson E, Butcher D, Lin FI, Choyke PL, Kelly K, Jagoda EM. Monitoring PSMA Responses to ADT in Prostate Cancer Patient-Derived Xenograft Mouse Models Using [ 18F]DCFPyL PET Imaging. Mol Imaging Biol 2021; 23:745-755. [PMID: 33891265 PMCID: PMC9910584 DOI: 10.1007/s11307-021-01605-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/30/2021] [Accepted: 04/05/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE PSMA overexpression has been associated with aggressive prostate cancer (PCa). However, PSMA PET imaging has revealed highly variable changes in PSMA expression in response to ADT treatment ranging from increases to moderate decreases. To better understand these PSMA responses and potential relationship to progressive PCa, the PET imaging agent, [18F]DCFPyL, was used to assess changes in PSMA expression in response to ADT using genomically characterized LuCaP patient-derived xenograft mouse models (LuCaP-PDXs) which were found to be sensitive to ADT (LuCaP73 and LuCaP136;CS) or resistant (LuCaP167;CR). METHODS [18F]DCFPyL (2-(3-{1-carboxy-5-[(6-[18F]fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid) was used to assess PSMA in vitro (saturation assays) in LuCaP tumor membrane homogenates and in vivo (imaging/biodistribution) in LuCaP-PDXs. Control and ADT-treated LuCaPs were imaged before ADT (0 days) and 2-, 7-, 14-, and 21-days post-ADT from which tumor:muscle ratios (T:Ms) were determined and concurrently tumor volumes were measured (caliper). After the 21-day imaging, biodistributions and histologic/genomic (PSMA, AR) analysis were done. RESULTS [18F]DCFPyL exhibited high affinity for PSMA and distinguished different levels of PSMA in LuCaP tumors. Post-ADT CS LuCaP73 and LuCaP136 tumor volumes significantly decreased at day 7 or 14 respectively vs controls, whereas the CR LuCaP167 tumor volumes were minimally changed. [18F]DCFPyL imaging T:Ms were increased 3-5-fold in treated LuCaP73 tumors vs controls, while treated LuCaP136 T:Ms remained unchanged which was confirmed by day 21 biodistribution results. For treated LuCaP167, T:Ms were decreased (~ 45 %) vs controls but due to low T:M values (<2) may not be indicative of PSMA level changes. LuCaP73 tumor PSMA histologic/genomic results were comparable to imaging/biodistribution results, whereas the results for other tumor types varied. CONCLUSION Tumor responses to ADT varied from sensitive to resistant among these LuCaP PDXs, while only the high PSMA expressing LuCaP model exhibited an increase in PSMA levels in response to ADT. These models may be useful in understanding the clinical relevance of PSMA PET responses to ADT and potentially the relationship to disease progression as it may relate to the genomic signature.
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Affiliation(s)
- Jyoti Roy
- Molecular Imaging Program, NCI/NIH, Center for Cancer Research, National Cancer Institute, Building 10, Room B3B406, Bethesda, MD, 20892, USA
| | - Margaret E. White
- Laboratory of Genitourinary Cancer Pathogenesis NCI/NIH, Bethesda, MD, USA
| | - Falguni Basuli
- Chemistry and Synthesis Center, NHLBI/NIH, Rockville, MD, USA
| | | | - Karen Wong
- Molecular Imaging Program, NCI/NIH, Center for Cancer Research, National Cancer Institute, Building 10, Room B3B406, Bethesda, MD, 20892, USA
| | - Morgan Riba
- Laboratory of Genitourinary Cancer Pathogenesis NCI/NIH, Bethesda, MD, USA
| | - Anita T. Ton
- Molecular Imaging Program, NCI/NIH, Center for Cancer Research, National Cancer Institute, Building 10, Room B3B406, Bethesda, MD, 20892, USA
| | - Xiang Zhang
- Chemistry and Synthesis Center, NHLBI/NIH, Rockville, MD, USA
| | - Keith H. Jansson
- Laboratory of Genitourinary Cancer Pathogenesis NCI/NIH, Bethesda, MD, USA
| | - Elijah Edmondson
- Pathology/Histotechnology Laboratory, Leidos, Inc./Frederick National Laboratory for Cancer Research, NCI, Frederick, MD, USA
| | - Donna Butcher
- Pathology/Histotechnology Laboratory, Leidos, Inc./Frederick National Laboratory for Cancer Research, NCI, Frederick, MD, USA
| | - Frank I. Lin
- Molecular Imaging Program, NCI/NIH, Center for Cancer Research, National Cancer Institute, Building 10, Room B3B406, Bethesda, MD, 20892, USA
| | - Peter L. Choyke
- Molecular Imaging Program, NCI/NIH, Center for Cancer Research, National Cancer Institute, Building 10, Room B3B406, Bethesda, MD, 20892, USA
| | - Kathleen Kelly
- Laboratory of Genitourinary Cancer Pathogenesis NCI/NIH, Bethesda, MD, USA
| | - Elaine M. Jagoda
- Molecular Imaging Program, NCI/NIH, Center for Cancer Research, National Cancer Institute, Building 10, Room B3B406, Bethesda, MD, 20892, USA
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12
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Roy J, Warner BM, Basuli F, Zhang X, Zheng C, Goldsmith C, Phelps T, Wong K, Ton AT, Pieschl R, White ME, Swenson R, Chiorini JA, Choyke PL, Lin FI. Competitive blocking of salivary gland [ 18F]DCFPyL uptake via localized, retrograde ductal injection of non-radioactive DCFPyL: a preclinical study. EJNMMI Res 2021; 11:66. [PMID: 34287731 PMCID: PMC8295433 DOI: 10.1186/s13550-021-00803-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/09/2021] [Indexed: 12/28/2022] Open
Abstract
Background PSMA-targeted radionuclide therapy (TRT) is a promising treatment for prostate cancer (PCa), but dose-limiting xerostomia can severely limit its clinical adaptation, especially when using alpha-emitting radionuclides. With [18F]DCFPyL as a surrogate for PSMA-TRT, we report a novel method to selectively reduce salivary gland (SG) uptake of systemically administered [18F]DCFPyL by immediate prior infusion of non-radioactive standard of [18F]DCFPyL (DCFPyL) directly into the SG via retrograde cannulation. Methods A dose-finding cohort using athymic nude mice demonstrated proof of principle that SG uptake can be selectively blocked by DCFPyL administered either locally via cannulation (CAN group) or systemically (SYS group). The experiments were repeated in a validation cohort of 22RV1 tumor-bearing mice. Submandibular glands (SMG) of CAN mice were locally blocked with either saline or DCFPyL (dose range: 0.01× to 1000× molar equivalent of the radioactive [18F]DCFPyL dose). The radioactive dose of [18F]DCFPyL was administered systemically 10 min later and the mice euthanized after 1 h for biodistribution studies. Toxicity studies were done at up to 1000× dose. Results In the dose-finding cohort, the SYS group showed a dose-dependent 12–40% decrease in both the SMG T/B and the kidney (tumor surrogate). Mild blocking was observed at 0.01× , with maximal blocking reached at 1× with no additional blocking up to 1000× . In the CAN group, blocking at the 0.1× and 1× dose levels resulted in a similar 42–53% decrease, but without the corresponding decrease in kidney uptake as seen in the SYS group. Some evidence of “leakage” of DCFPyL from the salivary gland into the systemic circulation was observed. However, experiments in 22RV1 tumor-bearing mice at the 0.1× and 1× dose levels confirm that, at the appropriate blocking dose, SG uptake of [18F]DCFPyL can be selectively reduced without affecting tumor uptake and with no toxicity. Conclusion Our results suggest that direct retrograde instillation of DCFPyL into the SG could predictably and selectively decrease salivary uptake of systemically administered [18F]DCFPyL without altering tumor uptake, if given at the appropriate dose. This novel approach is easily translatable to clinical practice and has the potential to mitigate xerostomia, without compromising the therapeutic efficacy of the PSMA-TRT. Supplementary Information The online version contains supplementary material available at 10.1186/s13550-021-00803-9.
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Affiliation(s)
- Jyoti Roy
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH, NCI/NIH, Building 10, Room # B3B69F, Bethesda, MD, 20892, USA
| | - Blake M Warner
- National Institute of Dental and Craniofacial Research, NIH, Building 10, 1A08, Bethesda, MD, 20892, USA
| | - Falguni Basuli
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, NIH, Rockville, MD, USA
| | - Xiang Zhang
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, NIH, Rockville, MD, USA
| | - Changyu Zheng
- National Institute of Dental and Craniofacial Research, NIH, Building 10, 1A08, Bethesda, MD, 20892, USA
| | - Corrine Goldsmith
- National Institute of Dental and Craniofacial Research, NIH, Building 10, 1A08, Bethesda, MD, 20892, USA
| | - Tim Phelps
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH, NCI/NIH, Building 10, Room # B3B69F, Bethesda, MD, 20892, USA
| | - Karen Wong
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH, NCI/NIH, Building 10, Room # B3B69F, Bethesda, MD, 20892, USA
| | - Anita T Ton
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH, NCI/NIH, Building 10, Room # B3B69F, Bethesda, MD, 20892, USA
| | - Rick Pieschl
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, NIH, Rockville, MD, USA
| | - Margaret E White
- Laboratory of Genitourinary Cancer Pathogenesis, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Rolf Swenson
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, NIH, Rockville, MD, USA
| | - John A Chiorini
- National Institute of Dental and Craniofacial Research, NIH, Building 10, 1A08, Bethesda, MD, 20892, USA
| | - Peter L Choyke
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH, NCI/NIH, Building 10, Room # B3B69F, Bethesda, MD, 20892, USA
| | - Frank I Lin
- Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, NIH, NCI/NIH, Building 10, Room # B3B69F, Bethesda, MD, 20892, USA.
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Abstract
ABSTRACT Significant 68Ga-PSMA-11 activity is commonly observed in the lacrimal and salivary glands on PSMA PET/CT. An 80-year-old man after radical prostatectomy was evaluated with 68Ga-PSMA-11 PET/CT. There was no obvious PSMA uptake in the bilateral lacrimal, parotid, and submandibular glands. Subsequently, based on laboratory examination results and 99mTcO4 salivary gland scintigraphy, this patient was diagnosed with Sjögren syndrome, which accounted for the absence of uptake by the glands. This case showed the potential of 68Ga-PSMA-11 PET/CT in the evaluation of the lacrimal glands and major salivary glands.
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Affiliation(s)
- Rou Li
- From the Department of Nuclear Medicine, Shanghai Changhai Hospital, Shanghai, China
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14
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Ruigrok EAM, van Vliet N, Dalm SU, de Blois E, van Gent DC, Haeck J, de Ridder C, Stuurman D, Konijnenberg MW, van Weerden WM, de Jong M, Nonnekens J. Extensive preclinical evaluation of lutetium-177-labeled PSMA-specific tracers for prostate cancer radionuclide therapy. Eur J Nucl Med Mol Imaging 2021; 48:1339-1350. [PMID: 33094433 PMCID: PMC8113296 DOI: 10.1007/s00259-020-05057-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/24/2020] [Indexed: 01/13/2023]
Abstract
PURPOSE Various radiolabeled prostate-specific membrane antigen (PSMA)-targeting tracers are clinically applied for prostate cancer (PCa) imaging and targeted radionuclide therapy. The PSMA binding affinities, biodistribution, and DNA-damaging capacities of these radiotracers have not yet been compared in detail. A major concern of PSMA-targeting radiotracers is the toxicity in other PSMA-expressing organs, such as the salivary glands, thus demanding careful evaluation of the most optimal and safest radiotracer. In this extensive preclinical study, we evaluated the clinically applied PSMA-targeting small molecule inhibitors DOTA-PSMA-617 (PSMA-617) and DOTAGA-PSMA-I&T (PSMA-I&T) and the PSMA nanobody DOTA-JVZ-007 (JVZ-007) using PSMA-expressing cell lines, a unique set of PCa patient-derived xenografts (PDX) and healthy human tissues. METHODS AND RESULTS In vitro displacement studies on PSMA-expressing cells and cryosections of a PSMA-positive PDX revealed high and specific binding affinity for all three tracers labeled with lutetium-177 with IC50 values in the nanomolar range. Interestingly, [177Lu]Lu-JVZ-007 could not be displaced by PSMA-617 or PSMA-I&T, suggesting that this tracer targets an alternative binding site. Autoradiography assays on cryosections of human salivary and renal tissues revealed [177Lu]Lu-PSMA-617 to have the lowest binding to these healthy organs compared with [177Lu]Lu-PSMA-I&T. In vivo biodistribution assays confirmed the in vitro results with comparable tumor uptake of [177Lu]Lu-PSMA-617 and [177Lu]Lu-PSMA-I&T at all timepoints, resulting in induction of similar levels of DNA double-strand breaks in the tumors. However, [177Lu]Lu-PSMA-I&T demonstrated approximately 40× higher renal uptake at 4 and 8 h post injection resulting in an unfavorable tumor-to-kidney ratio. CONCLUSION [177Lu]Lu-PSMA-617 has the most favorable biodistribution in mice as well as more favorable binding characteristics in vitro in PSMA-positive cells and human kidney and salivary gland specimens compared with [177Lu]Lu-PSMA-I&T and [177Lu]Lu-JVZ-007. Based on our preclinical evaluation, [177Lu]Lu-PSMA-617 is the best performing tracer to be taken further into clinical evaluation for PSMA-targeted radiotherapeutic development although with careful evaluation of the tracer binding to PSMA-expressing organs.
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Affiliation(s)
- Eline A M Ruigrok
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
- Department of Experimental Urology, Erasmus MC, Rotterdam, The Netherlands
| | - Nicole van Vliet
- Department of Molecular Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Simone U Dalm
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Erik de Blois
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Dik C van Gent
- Department of Molecular Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Joost Haeck
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Corrina de Ridder
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
- Department of Experimental Urology, Erasmus MC, Rotterdam, The Netherlands
| | - Debra Stuurman
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
- Department of Experimental Urology, Erasmus MC, Rotterdam, The Netherlands
| | - Mark W Konijnenberg
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | | | - Marion de Jong
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Julie Nonnekens
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands.
- Department of Molecular Genetics, Erasmus MC, Rotterdam, The Netherlands.
- Oncode Institute, Erasmus MC, Rotterdam, The Netherlands.
- Erasmus MC, Room Ee757R, PO box 2040, 3000, CA, Rotterdam, The Netherlands.
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15
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Kuo HT, Lin KS, Zhang Z, Uribe CF, Merkens H, Zhang C, Bénard F. 177Lu-Labeled Albumin-Binder-Conjugated PSMA-Targeting Agents with Extremely High Tumor Uptake and Enhanced Tumor-to-Kidney Absorbed Dose Ratio. J Nucl Med 2021; 62:521-527. [PMID: 32859704 PMCID: PMC8049373 DOI: 10.2967/jnumed.120.250738] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 07/29/2020] [Indexed: 12/22/2022] Open
Abstract
The use of an albumin binder has been shown to improve tumor uptake of prostate-specific membrane antigen (PSMA)-targeting radiotherapeutic agents. The aim of this study was to develop improved radiotherapeutic agents that combine an optimized affinity-modifying group and optimized albumin binders to maximize the tumor-to-kidney absorbed dose ratio. Methods:68Ga-labeled DOTA-conjugated lysine-ureido-glutamate-based PSMA-targeting agents bearing various affinity-modifying groups or albumin binders were synthesized and evaluated by PET/CT imaging and biodistribution studies in LNCaP tumor-bearing mice. The optimized affinity-modifying group and albumin binders were combined, and the resulting derivatives were radiolabeled with 177Lu and evaluated by SPECT/CT imaging and biodistribution studies in LNCaP tumor-bearing mice. Radiation dosimetry was calculated using the OLINDA/EXM software. Results: Affinity-modifying group optimization revealed that 68Ga-HTK03041 bearing a tranexamic acid-9-anthrylalanine affinity-modifying group had the highest tumor uptake (23.1 ± 6.11 percentage injected dose [%ID]/g at 1 h after injection). Albumin binder optimization showed that 68Ga-HTK03055 and 68Ga-HTK03086 bearing the N-(4-(p-chlorophenyl)butanoyl)-Gly and N-(4-(p-methoxyphenyl)butanoyl)-Gly motifs, respectively, had relatively faster tumor accumulation (∼30 %ID/g at 3 h after injection) and lower average kidney uptake (<55 %ID/g at both 1 and 3 h after injection). Combining the tranexamic acid-9-anthrylalanine affinity-modifying group with N-(4-(p-chlorophenyl)butanoyl)-Gly and N-(4-(p-methoxyphenyl)butanoyl)-Gly albumin-binding motifs generated HTK03121 and HTK03123, respectively. 177Lu-HTK03121 and 177Lu-HTK03123 had extremely high peak uptake (104 ± 20.3 and 70.8 ± 23.7 %ID/g, respectively) in LNCaP tumor xenografts, and this peak was sustained up to 120 h after injection. Dosimetry calculation showed that compared with 177Lu-PSMA-617, 177Lu-HTK03121 and 177Lu-HTK03123 delivered 18.7- and 12.7-fold higher absorbed dose to tumor but only 6.4- and 6.3-fold higher absorbed dose to kidneys, leading to 2.9- and 2.0-fold improvement in the tumor-to-kidney absorbed dose ratios. Conclusion: With greatly enhanced tumor uptake and tumor-to-kidney absorbed dose ratio, 177Lu-HTK03121 and 177Lu-HTK03123 have the potential to improve treatment efficacy using significantly lower quantities of 177Lu and are promising candidates for clinical translation to treat metastatic castration-resistant prostate cancer.
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Affiliation(s)
- Hsiou-Ting Kuo
- Department of Molecular Oncology, BC Cancer, Vancouver, British Columbia, Canada
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, BC Cancer, Vancouver, British Columbia, Canada
- Department of Functional Imaging, BC Cancer, Vancouver, British Columbia, Canada; and
- Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Zhengxing Zhang
- Department of Molecular Oncology, BC Cancer, Vancouver, British Columbia, Canada
| | - Carlos F Uribe
- Department of Functional Imaging, BC Cancer, Vancouver, British Columbia, Canada; and
| | - Helen Merkens
- Department of Molecular Oncology, BC Cancer, Vancouver, British Columbia, Canada
| | - Chengcheng Zhang
- Department of Molecular Oncology, BC Cancer, Vancouver, British Columbia, Canada
| | - François Bénard
- Department of Molecular Oncology, BC Cancer, Vancouver, British Columbia, Canada
- Department of Functional Imaging, BC Cancer, Vancouver, British Columbia, Canada; and
- Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
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Felber VB, Valentin MA, Wester HJ. Design of PSMA ligands with modifications at the inhibitor part: an approach to reduce the salivary gland uptake of radiolabeled PSMA inhibitors? EJNMMI Radiopharm Chem 2021; 6:10. [PMID: 33638060 PMCID: PMC7910394 DOI: 10.1186/s41181-021-00124-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/22/2021] [Indexed: 12/14/2022] Open
Abstract
AIM To investigate whether modifications of prostate-specific membrane antigen (PSMA)-targeted radiolabeled urea-based inhibitors could reduce salivary gland uptake and thus improve tumor-to-salivary gland ratios, several analogs of a high affinity PSMA ligand were synthesized and evaluated in in vitro and in vivo studies. METHODS Binding motifs were synthesized 'on-resin' or, when not practicable, in solution. Peptide chain elongations were performed according to optimized standard protocols via solid-phase peptide synthesis. In vitro experiments were performed using PSMA+ LNCaP cells. In vivo studies as well as μSPECT/CT scans were conducted with male LNCaP tumor xenograft-bearing CB17-SCID mice. RESULTS PSMA ligands with A) modifications within the central Zn2+-binding unit, B) proinhibitor motifs and C) substituents & bioisosteres of the P1'-γ-carboxylic acid were synthesized and evaluated. Modifications within the central Zn2+-binding unit of PSMA-10 (Glu-urea-Glu) provided three compounds. Thereof, only natLu-carbamate I (natLu-3) exhibited high affinity (IC50 = 7.1 ± 0.7 nM), but low tumor uptake (5.31 ± 0.94% ID/g, 1 h p.i. and 1.20 ± 0.55% ID/g, 24 h p.i.). All proinhibitor motif-based ligands (three in total) exhibited low binding affinities (> 1 μM), no notable internalization and very low tumor uptake (< 0.50% ID/g). In addition, four compounds with P1'-ɣ-carboxylate substituents were developed and evaluated. Thereof, only tetrazole derivative natLu-11 revealed high affinity (IC50 = 16.4 ± 3.8 nM), but also this inhibitor showed low tumor uptake (3.40 ± 0.63% ID/g, 1 h p.i. and 0.68 ± 0.16% ID/g, 24 h p.i.). Salivary gland uptake in mice remained at an equally low level for all compounds (between 0.02 ± 0.00% ID/g and 0.09 ± 0.03% ID/g), wherefore apparent tumor-to-submandibular gland and tumor-to-parotid gland ratios for the modified peptides were distinctly lower (factor 8-45) than for [177Lu]Lu-PSMA-10 at 24 h p.i. CONCLUSIONS The investigated compounds could not compete with the in vivo characteristics of the EuE-based PSMA inhibitor [177Lu]Lu-PSMA-10. Although two derivatives (3 and 11) were found to exhibit high affinities towards LNCaP cells, tumor uptake at 24 h p.i. was considerably low, while uptake in salivary glands remained unaffected. Optimization of the established animal model should be envisaged to enable a clear identification of PSMA-targeting radioligands with improved tumor-to-salivary gland ratios in future studies.
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Affiliation(s)
- Veronika Barbara Felber
- Technical University of Munich, Chair of Pharmaceutical Radiochemistry, Walther-Meißner-Str. 3, 85748, Garching, Germany.
| | - Manuel Amando Valentin
- Technical University of Munich, Chair of Pharmaceutical Radiochemistry, Walther-Meißner-Str. 3, 85748, Garching, Germany
| | - Hans-Jürgen Wester
- Technical University of Munich, Chair of Pharmaceutical Radiochemistry, Walther-Meißner-Str. 3, 85748, Garching, Germany
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Juzeniene A, Stenberg VY, Bruland ØS, Larsen RH. Preclinical and Clinical Status of PSMA-Targeted Alpha Therapy for Metastatic Castration-Resistant Prostate Cancer. Cancers (Basel) 2021; 13:779. [PMID: 33668474 PMCID: PMC7918517 DOI: 10.3390/cancers13040779] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/07/2021] [Accepted: 02/08/2021] [Indexed: 12/14/2022] Open
Abstract
Bone, lymph node, and visceral metastases are frequent in castrate-resistant prostate cancer patients. Since such patients have only a few months' survival benefit from standard therapies, there is an urgent need for new personalized therapies. The prostate-specific membrane antigen (PSMA) is overexpressed in prostate cancer and is a molecular target for imaging diagnostics and targeted radionuclide therapy (theragnostics). PSMA-targeted α therapies (PSMA-TAT) may deliver potent and local radiation more selectively to cancer cells than PSMA-targeted β- therapies. In this review, we summarize both the recent preclinical and clinical advances made in the development of PSMA-TAT, as well as the availability of therapeutic α-emitting radionuclides, the development of small molecules and antibodies targeting PSMA. Lastly, we discuss the potentials, limitations, and future perspectives of PSMA-TAT.
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Affiliation(s)
- Asta Juzeniene
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway;
| | - Vilde Yuli Stenberg
- Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway;
- Nucligen, Ullernchausséen 64, 0379 Oslo, Norway;
- Institute for Clinical Medicine, University of Oslo, Box 1171 Blindern, 0318 Oslo, Norway;
| | - Øyvind Sverre Bruland
- Institute for Clinical Medicine, University of Oslo, Box 1171 Blindern, 0318 Oslo, Norway;
- Department of Oncology, Norwegian Radium Hospital, Oslo University Hospital, 0379 Oslo, Norway
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Harsini S, Saprunoff H, Alden T, Mohammadi B, Wilson D, Bénard F. The Effects of Monosodium Glutamate on PSMA Radiotracer Uptake in Men with Recurrent Prostate Cancer: A Prospective, Randomized, Double-Blind, Placebo-Controlled Intraindividual Imaging Study. J Nucl Med 2020; 62:81-87. [DOI: 10.2967/jnumed.120.246983] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 04/13/2020] [Indexed: 02/06/2023] Open
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