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Hunter C, Larimer B. Chemokine receptor PET imaging: Bridging molecular insights with clinical applications. Nucl Med Biol 2024; 134-135:108912. [PMID: 38691942 PMCID: PMC11180593 DOI: 10.1016/j.nucmedbio.2024.108912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 03/07/2024] [Accepted: 04/16/2024] [Indexed: 05/03/2024]
Abstract
Chemokine receptors are important components of cellular signaling and play a critical role in directing leukocytes during inflammatory reactions. Their importance extends to numerous pathological processes, including tumor differentiation, angiogenesis, metastasis, and associations with multiple inflammatory disorders. The necessity to monitor the in vivo interactions of cellular chemokine receptors has been driven the recent development of novel positron emission tomography (PET) imaging agents. This imaging modality provides non-invasive localization and quantitation of these receptors that cannot be provided through blood or tissue-based assays. Herein, we provide a review of PET imaging of the chemokine receptors that have been imaged to date, namely CXCR3, CXCR4, CCR2, CCR5, and CMKLR1. The quantification of these receptors can aid in understanding various diseases, including cancer, atherosclerosis, idiopathic pulmonary fibrosis, and acute respiratory distress syndrome. The development of specific radiotracers targeting these receptors will be discussed, including promising results for disease diagnosis and management. However, challenges persist in fully translating these imaging advancements into practical therapeutic applications. Given the success of CXCR4 PET imaging to date, future research should focus on clinical translation of these approaches to understand their role in the management of a wide variety of diseases.
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Affiliation(s)
- Chanelle Hunter
- Graduate Biomedical Sciences Cancer Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Benjamin Larimer
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, AL 35294, USA.
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2
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Tripathy RK, Pande AH. Molecular and functional insight into anti-EGFR nanobody: Theranostic implications for malignancies. Life Sci 2024; 345:122593. [PMID: 38554946 DOI: 10.1016/j.lfs.2024.122593] [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: 01/09/2024] [Revised: 02/27/2024] [Accepted: 03/24/2024] [Indexed: 04/02/2024]
Abstract
Targeted therapy and imaging are the most popular techniques for the intervention and diagnosis of cancer. A potential therapeutic target for the treatment of cancer is the epidermal growth factor receptor (EGFR), primarily for glioblastoma, lung, and breast cancer. Over-production of ligand, transcriptional up-regulation due to autocrine/paracrine signalling, or point mutations at the genomic locus may contribute to the malfunction of EGFR in malignancies. This exploit makes use of EGFR, an established biomarker for cancer diagnostics and treatment. Despite considerable development in the last several decades in making EGFR inhibitors, they are still not free from limitations like toxicity and a short serum half-life. Nanobodies and antibodies share similar binding properties, but nanobodies have the additional advantage that they can bind to antigenic epitopes deep inside the target that conventional antibodies are unable to access. For targeted therapy, anti-EGFR nanobodies can be conjugated to various molecules such as drugs, peptides, toxins and photosensitizers. These nanobodies can be designed as novel immunoconjugates using the universal modular antibody-based platform technology (UniCAR). Furthermore, Anti-EGFR nanobodies can be expressed in neural stem cells and visualised by effective fluorescent and radioisotope labelling.
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Affiliation(s)
- Rajan K Tripathy
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, (Mohali) 160062, Punjab, India
| | - Abhay H Pande
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, (Mohali) 160062, Punjab, India.
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3
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Quigley NG, Steiger K, Färber SF, Richter F, Weichert W, Notni J. Sensitive Positron Emission Tomography Imaging of PD-L1 Expression in Human Breast and Lung Carcinoma Xenografts Using the Radiometalated Peptide Ga-68-TRAP-WL12. Mol Pharm 2024; 21:1827-1837. [PMID: 38291706 DOI: 10.1021/acs.molpharmaceut.3c01128] [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] [Indexed: 02/01/2024]
Abstract
Noninvasive imaging of the immune checkpoint protein programmed death ligand 1 (PD-L1; synonyms: CD274, B7-H1) holds great promise to improve patient selection and, thus, response rates for immune checkpoint therapy (ICT) with monoclonal antibodies targeting the PD1/PD-L1 axis. The PD-L1 specific peptide WL12 (cyclo(AcY-(NMe)A-N-P-H-L-Hyp-W-S-W(Me)-(NMe)Nle-(NMe)Nle-O-C)-G-NH2) was functionalized with the Gallium-68 chelator TRAP by means of click chemistry (CuAAC). The resulting conjugate TRAP-WL12 was labeled with Gallium-68 within 16 min, with approximately 90% radiochemical yield and 99% radiochemical purity, affording Ga-68-TRAP-WL12 with molar activities typically exceeding 100 MBq/nmol. This radiotracer was characterized by positron emission tomography (PET) imaging and ex vivo biodistribution in murine xenografts of nontransfected PD-L1 expressing tumor cell lines, MDA-MB-231 (human breast carcinoma), and H2009 (human lung adenocarcinoma). It showed a favorable biodistribution profile with rapid renal clearance and low background (tumor-to-blood ratio = 26.6, 3 h p.i.). Conjugation of the Ga-68-TRAP moiety to WL12 successfully mitigated the nonspecific uptake of this peptide in organs, particularly the liver. This was demonstrated by comparing Ga-68-TRAP-WL12 with the archetypical Ga-68-DOTA-WL12, for which tumor-to-liver ratios of 1.4 and 0.5, respectively, were found. Although immunohistochemistry (IHC) revealed a low PD-L1 expression in MDA-MB-213 and H2009 xenografts that corresponds well to the clinical situation, PET showed high tumor uptakes (6.6 and 7.3% injected activity per gram of tissue (iA/g), respectively) for Ga-68-TRAP-WL12. Thus, this tracer has the potential for routine clinical PD-L1 PET imaging because it detects even very low PD-L1 expression densities with high sensitivity and may open an avenue to replace PD-L1 IHC of biopsies as the standard means to select potential responders for ICT.
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Affiliation(s)
- Neil Gerard Quigley
- Institute of Pathology, School of Medicine, Technische Universität München, Trogerstr. 18, München D-81675, Germany
| | - Katja Steiger
- Institute of Pathology, School of Medicine, Technische Universität München, Trogerstr. 18, München D-81675, Germany
| | - Stefanie Felicitas Färber
- Institute of Pathology, School of Medicine, Technische Universität München, Trogerstr. 18, München D-81675, Germany
| | - Frauke Richter
- Institute of Pathology, School of Medicine, Technische Universität München, Trogerstr. 18, München D-81675, Germany
| | - Wilko Weichert
- Institute of Pathology, School of Medicine, Technische Universität München, Trogerstr. 18, München D-81675, Germany
| | - Johannes Notni
- Institute of Pathology, School of Medicine, Technische Universität München, Trogerstr. 18, München D-81675, Germany
- TRIMT GmbH, Carl-Eschebach-Str. 7, Radeberg D-01454, Germany
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4
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Bamminger K, Pichler V, Vraka C, Limberger T, Moneva B, Pallitsch K, Lieder B, Zacher AS, Ponti S, Benčurová K, Yang J, Högler S, Kodajova P, Kenner L, Hacker M, Wadsak W. Development and In Vivo Evaluation of Small-Molecule Ligands for Positron Emission Tomography of Immune Checkpoint Modulation Targeting Programmed Cell Death 1 Ligand 1. J Med Chem 2024; 67:4036-4062. [PMID: 38442487 PMCID: PMC10945501 DOI: 10.1021/acs.jmedchem.3c02342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/15/2024] [Accepted: 02/21/2024] [Indexed: 03/07/2024]
Abstract
A substantial portion of patients do not benefit from programmed cell death protein 1/programmed cell death 1 ligand 1 (PD-1/PD-L1) checkpoint inhibition therapies, necessitating a deeper understanding of predictive biomarkers. Immunohistochemistry (IHC) has played a pivotal role in assessing PD-L1 expression, but small-molecule positron emission tomography (PET) tracers could offer a promising avenue to address IHC-associated limitations, i.e., invasiveness and PD-L1 expression heterogeneity. PET tracers would allow for improved quantification of PD-L1 through noninvasive whole-body imaging, thereby enhancing patient stratification. Here, a large series of PD-L1 targeting small molecules were synthesized, leveraging advantageous substructures to achieve exceptionally low nanomolar affinities. Compound 5c emerged as a promising candidate (IC50 = 10.2 nM) and underwent successful carbon-11 radiolabeling. However, a lack of in vivo tracer uptake in xenografts and notable accumulation in excretory organs was observed, underscoring the challenges encountered in small-molecule PD-L1 PET tracer development. The findings, including structure-activity relationships and in vivo biodistribution data, stand to illuminate the path forward for refining small-molecule PD-L1 PET tracers.
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Affiliation(s)
- Karsten Bamminger
- CBmed
GmbH - Center for Biomarker Research in Medicine, 8010 Graz, Austria
- Department
of Biomedical Imaging and Image-guided Therapy, Division of Nuclear
Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Verena Pichler
- CBmed
GmbH - Center for Biomarker Research in Medicine, 8010 Graz, Austria
- Department
of Pharmaceutical Sciences, Division of Pharmaceutical Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Chrysoula Vraka
- Department
of Biomedical Imaging and Image-guided Therapy, Division of Nuclear
Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Tanja Limberger
- CBmed
GmbH - Center for Biomarker Research in Medicine, 8010 Graz, Austria
- Institute
of Clinical Pathology, Medical University
of Vienna, 1090 Vienna, Austria
| | - Boryana Moneva
- Department
of Biomedical Imaging and Image-guided Therapy, Division of Nuclear
Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | | | - Barbara Lieder
- Institute
of Physiological Chemistry, University of
Vienna, 1090 Vienna, Austria
- Institute
of Clinical Nutrition, University of Hohenheim, 70599 Stuttgart, Germany
| | - Anna Sophia Zacher
- Department
of Biomedical Imaging and Image-guided Therapy, Division of Nuclear
Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Stefanie Ponti
- Department
of Biomedical Imaging and Image-guided Therapy, Division of Nuclear
Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Katarína Benčurová
- Department
of Biomedical Imaging and Image-guided Therapy, Division of Nuclear
Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Jiaye Yang
- Institute
of Clinical Pathology, Medical University
of Vienna, 1090 Vienna, Austria
| | - Sandra Högler
- Unit
of Laboratory Animal Pathology, University
of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Petra Kodajova
- Unit
of Laboratory Animal Pathology, University
of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Lukas Kenner
- CBmed
GmbH - Center for Biomarker Research in Medicine, 8010 Graz, Austria
- Institute
of Clinical Pathology, Medical University
of Vienna, 1090 Vienna, Austria
- Unit
of Laboratory Animal Pathology, University
of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Marcus Hacker
- Department
of Biomedical Imaging and Image-guided Therapy, Division of Nuclear
Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Wolfgang Wadsak
- CBmed
GmbH - Center for Biomarker Research in Medicine, 8010 Graz, Austria
- Department
of Biomedical Imaging and Image-guided Therapy, Division of Nuclear
Medicine, Medical University of Vienna, 1090 Vienna, Austria
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Kiem D, Ocker M, Greil R, Neureiter D, Melchardt T. Enhancing anti-CD274 (PD-L1) targeting through combinatorial immunotherapy with bispecific antibodies and fusion proteins: from preclinical to phase II clinical trials. Expert Opin Investig Drugs 2024; 33:229-242. [PMID: 38354028 DOI: 10.1080/13543784.2024.2319317] [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: 12/03/2023] [Accepted: 02/12/2024] [Indexed: 02/24/2024]
Abstract
INTRODUCTION Immune checkpoint inhibitors have achieved great success in the treatment of many different types of cancer. Programmed cell death protein ligand 1 (PD-L1, CD274) is a major immunosuppressive immune checkpoint and a target for several already approved monoclonal antibodies. Despite this, novel strategies are under development, as the overall response remains low. AREAS COVERED In this review, an overview of the current biomarkers for response to PD-L1 inhibitor treatment is given, followed by a discussion of potential novel biomarkers, including tumor mutational burden and circulating tumor DNA. Combinatorial immunotherapy is a potential novel strategy to increase the response to PD-L1 inhibitor treatment and currently, several interesting bispecific antibodies as well as bispecific fusion proteins are undergoing early clinical investigation. We focus on substances targeting PD-L1 and a secondary target, and a secondary immunomodulatory target like CTLA-4, TIGIT, or CD47. EXPERT OPINION Overall, the presented studies show anti-tumor activity of these combinatorial immunotherapeutic approaches. However, still relatively low response rates suggest a need for better biomarkers.
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Affiliation(s)
- Dominik Kiem
- III Medical Department, Paracelsus Medical University, Salzburg, Austria
| | - Matthias Ocker
- Medical Department, Division of Hematology, Oncology, and Cancer Immunology, Campus, Charité Mitte, Charité University Medicine Berlin, Berlin, Germany
- EO Translational Insights Consulting GmbH, Berlin, Germany
- Tacalyx GmbH, Berlin, Germany
| | - Richard Greil
- III Medical Department, Paracelsus Medical University, Salzburg, Austria
- Cancer Cluster Salzburg, Salzburg, Austria
| | - Daniel Neureiter
- Cancer Cluster Salzburg, Salzburg, Austria
- Institute of Pathology, Paracelsus Medical University, University Hospital Salzburg (SALK), Salzburg, Austria
| | - Thomas Melchardt
- III Medical Department, Paracelsus Medical University, Salzburg, Austria
- Cancer Cluster Salzburg, Salzburg, Austria
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Krutzek F, Donat CK, Stadlbauer S. Chelator impact: investigating the pharmacokinetic behavior of copper-64 labeled PD-L1 radioligands. EJNMMI Radiopharm Chem 2024; 9:14. [PMID: 38372838 PMCID: PMC10876507 DOI: 10.1186/s41181-024-00243-5] [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: 10/24/2023] [Accepted: 02/05/2024] [Indexed: 02/20/2024] Open
Abstract
BACKGROUND Programmed cell death ligand 1 (PD-L1) plays a critical role in the tumor microenvironment and overexpression in several solid cancers has been reported. This was associated with a downregulation of the local immune response, specifically of T-cells. Immune checkpoint inhibitors showed a potential to break this localized immune paralysis, but only 30% of patients are considered responders. New diagnostic approaches are therefore needed to determine patient eligibility. Small molecule radiotracers targeting PD-L1, may serve as such diagnostic tools, addressing the heterogeneous PD-L1 expression between and within tumor lesions, thus aiding in therapy decisions. RESULTS Four biphenyl-based small-molecule PD-L1 ligands were synthesized using a convergent synthetic route with a linear sequence of up to eleven steps. As a chelator NODA-GA, CB-TE2A or DiAmSar was used to allow radiolabeling with copper-64 ([64Cu]Cu-14-[64Cu]Cu-16). In addition, a dimeric structure based on DiAmSar was synthesized ([64Cu]Cu-17). All four radioligands exhibited high proteolytic stability (> 95%) up to 48 h post-radiolabeling. Saturation binding yielded moderate affinities toward PD-L1, ranging from 100 to 265 nM. Real-time radioligand binding provided more promising KD values around 20 nM for [64Cu]Cu-14 and [64Cu]Cu-15. In vivo PET imaging in mice bearing both PC3 PD-L1 overexpressing and PD-L1-mock tumors was performed at 0-2, 4-5 and 24-25 h post injection (p.i.). This revealed considerably different pharmacokinetic profiles, depending on the substituted chelator. [64Cu]Cu-14, substituted with NODA-GA, showed renal clearance with low liver uptake, whereas substitution with the cross-bridged cyclam chelator CB-TE2A resulted in a primarily hepatobiliary clearance. Notably, the monomeric DiAmSar radioligand [64Cu]Cu-16 demonstrated a higher liver uptake than [64Cu]Cu-15, but was still renally cleared as evidenced by the lack of uptake in gall bladder and intestines. The dimeric structure [64Cu]Cu-17 showed extensive accumulation and trapping in the liver but was also cleared via the renal pathway. Of all tracer candidates and across all timepoints, [64Cu]Cu-17 showed the highest accumulation at 24 h p.i. in the PD-L1-overexpressing tumor of all timepoints and all radiotracers, indicating drastically increased circulation time upon dimerization of two PD-L1 binding motifs. CONCLUSIONS This study shows that chelator choice significantly influences the pharmacokinetic profile of biphenyl-based small molecule PD-L1 radioligands. The NODA-GA-conjugated radioligand [64Cu]Cu-14 exhibited favorable renal clearance; however, the limited uptake in tumors suggests the need for structural modifications to the binding motif for future PD-L1 radiotracers.
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Affiliation(s)
- Fabian Krutzek
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328, Dresden, Germany
| | - Cornelius K Donat
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328, Dresden, Germany
| | - Sven Stadlbauer
- Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328, Dresden, Germany.
- School of Science, Faculty of Chemistry and Food Chemistry, Technical University Dresden, 01069, Dresden, Germany.
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7
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Ahmadi M, Ritter CA, von Woedtke T, Bekeschus S, Wende K. Package delivered: folate receptor-mediated transporters in cancer therapy and diagnosis. Chem Sci 2024; 15:1966-2006. [PMID: 38332833 PMCID: PMC10848714 DOI: 10.1039/d3sc05539f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 12/31/2023] [Indexed: 02/10/2024] Open
Abstract
Neoplasias pose a significant threat to aging society, underscoring the urgent need to overcome the limitations of traditional chemotherapy through pioneering strategies. Targeted drug delivery is an evolving frontier in cancer therapy, aiming to enhance treatment efficacy while mitigating undesirable side effects. One promising avenue utilizes cell membrane receptors like the folate receptor to guide drug transporters precisely to malignant cells. Based on the cellular folate receptor as a cancer cell hallmark, targeted nanocarriers and small molecule-drug conjugates have been developed that comprise different (bio) chemistries and/or mechanical properties with individual advantages and challenges. Such modern folic acid-conjugated stimuli-responsive drug transporters provide systemic drug delivery and controlled release, enabling reduced dosages, circumvention of drug resistance, and diminished adverse effects. Since the drug transporters' structure-based de novo design is increasingly relevant for precision cancer remediation and diagnosis, this review seeks to collect and debate the recent approaches to deliver therapeutics or diagnostics based on folic acid conjugated Trojan Horses and to facilitate the understanding of the relevant chemistry and biochemical pathways. Focusing exemplarily on brain and breast cancer, recent advances spanning 2017 to 2023 in conjugated nanocarriers and small molecule drug conjugates were considered, evaluating the chemical and biological aspects in order to improve accessibility to the field and to bridge chemical and biomedical points of view ultimately guiding future research in FR-targeted cancer therapy and diagnosis.
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Affiliation(s)
- Mohsen Ahmadi
- Leibniz Institute for Plasma Science and Technology (INP), Center for Innovation Competence (ZIK) Plasmatis Felix Hausdorff-Str. 2 17489 Greifswald Germany
| | - Christoph A Ritter
- Institute of Pharmacy, Section Clinical Pharmacy, University of Greifswald Greifswald Germany
| | - Thomas von Woedtke
- Leibniz Institute for Plasma Science and Technology (INP), Center for Innovation Competence (ZIK) Plasmatis Felix Hausdorff-Str. 2 17489 Greifswald Germany
- Institute for Hygiene and Environmental Medicine, Greifswald University Medical Center Ferdinand-Sauerbruch-Straße 17475 Greifswald Germany
| | - Sander Bekeschus
- Leibniz Institute for Plasma Science and Technology (INP), Center for Innovation Competence (ZIK) Plasmatis Felix Hausdorff-Str. 2 17489 Greifswald Germany
- Clinic and Policlinic for Dermatology and Venereology, Rostock University Medical Center Strempelstr. 13 18057 Rostock Germany
| | - Kristian Wende
- Leibniz Institute for Plasma Science and Technology (INP), Center for Innovation Competence (ZIK) Plasmatis Felix Hausdorff-Str. 2 17489 Greifswald Germany
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Fan X, Nijman HW, de Bruyn M, Elsinga PH. ImmunoPET provides a novel way to visualize the CD103 + tissue-resident memory T cell to predict the response of immune checkpoint inhibitors. EJNMMI Res 2024; 14:5. [PMID: 38182929 PMCID: PMC10769965 DOI: 10.1186/s13550-023-01062-6] [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: 07/20/2023] [Accepted: 12/17/2023] [Indexed: 01/07/2024] Open
Abstract
BACKGROUND Immune checkpoint inhibitors (ICIs) have made significant progress in oncotherapy improving survival of patients. However, the benefits are limited to only a small subgroup of patients who could achieve durable responses. Early prediction of response may enable treatment optimization and patient stratification. Therefore, developing appropriate biomarkers is critical to monitoring efficacy and assessing patient response to ICIs. MAIN BODY Herein, we first introduce a new potential biomarker, CD103, expressed on tissue-resident memory T cells, and discuss the potential application of CD103 PET imaging in predicting immune checkpoint inhibitor treatment. In addition, we describe the current targets of ImmunoPET and compare these targets with CD103. To assess the benefit of PET imaging, a comparative analysis between ImmunoPET and other imaging techniques commonly employed for tumor diagnosis was performed. Additionally, we compare ImmunoPET and immunohistochemistry (IHC), a widely utilized clinical method for biomarker identification with respect to visualizing the immune targets. CONCLUSION CD103 ImmunoPET is a promising method for determining tumor-infiltrating lymphocytes (TILs) load and response to ICIs, thereby addressing the lack of reliable biomarkers in cancer immunotherapy. Compared to general T cell markers, CD103 is a specific marker for tissue-resident memory T cells, which number increases during successful ICI therapy. ImmunoPET offers noninvasive, dynamic imaging of specific markers, complemented by detailed molecular information from immunohistochemistry (IHC). Radiomics can extract quantitative features from traditional imaging methods, while near-infrared fluorescence (NIRF) imaging aids tumor detection during surgery. In the era of precision medicine, combining such methods will offer a more comprehensive approach to cancer diagnosis and treatment.
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Affiliation(s)
- Xiaoyu Fan
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Hans W Nijman
- Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Marco de Bruyn
- Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Philip H Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
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Krutzek F, Donat CK, Ullrich M, Stadlbauer S. Design, Synthesis, and Biological Evaluation of Small-Molecule-Based Radioligands with Improved Pharmacokinetic Properties for Imaging of Programmed Death Ligand 1. J Med Chem 2023; 66:15894-15915. [PMID: 38038981 PMCID: PMC10726354 DOI: 10.1021/acs.jmedchem.3c01355] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/11/2023] [Accepted: 11/15/2023] [Indexed: 12/02/2023]
Abstract
Small molecules offer some advantages for developing positron emission tomography (PET) tracers and are therefore a promising approach for imaging and therapy monitoring of programmed death ligand 1 (PD-L1) positive tumors. Here, we report six biphenyl PD-L1 radioligands using the NODA-GA-chelator for efficient copper-64 complexation. These radioligands contain varying numbers of sulfonic and/or phosphonic acid groups, serving as hydrophilizing units to lower the log D7.4 value down to -4.28. The binding affinities of compounds were evaluated using saturation binding and a real-time binding assay, with a highest binding affinity of 21 nM. Small-animal PET imaging revealed vastly different pharmacokinetic profiles depending on the quantity and type of hydrophilizing units. Of the investigated radioligands, [64Cu]Cu-3 showed the most favorable kinetics in vitro. This was also found in vivo, with a predominantly renal clearance and a specific uptake in the PD-L1-overexpressing tumor. With further modifications, this compound could be a promising candidate for the imaging of PD-L1 in the clinical setting.
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Affiliation(s)
- Fabian Krutzek
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical
Cancer Research, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Cornelius K. Donat
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical
Cancer Research, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Martin Ullrich
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical
Cancer Research, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Sven Stadlbauer
- Helmholtz-Zentrum
Dresden-Rossendorf, Institute of Radiopharmaceutical
Cancer Research, Bautzner Landstraße 400, 01328 Dresden, Germany
- Faculty
of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, Mommsenstraße 4, 01069 Dresden, Germany
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10
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Zhu D, Xu X, Zou P, Liu Y, Wang H, Han G, Lu C, Xie M. Synthesis and preliminary biological evaluation of a novel 99mTc-labeled small molecule for PD-L1 imaging. Bioorg Med Chem Lett 2023; 96:129496. [PMID: 37797805 DOI: 10.1016/j.bmcl.2023.129496] [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: 07/10/2023] [Revised: 09/26/2023] [Accepted: 10/02/2023] [Indexed: 10/07/2023]
Abstract
In recent years, PD-1/PD-L1 checkpoint blockade immunotherapy with remarkable efficacy has set off a heat wave. The expression level of PD-L1, which plays a predictive role in anti-PD-1/PD-L1 therapy, could be quantified by noninvasive imaging with radiotracers. Herein, we introduced the synthesis and preliminary biological evaluation of a novel 99mTc-labeled small molecule radiotracer [99mTc]G3C-CBM for PD-L1 imaging. [99mTc]G3C-CBM was achieved with high radiochemical purity (>96 %) and remained good stability in PBS and FBS. In competitive combination experiment, [99mTc]G3C-CBM was displaced by increasing concentrations of unlabeled G3C-CBM, resulting in an IC50 value of 41.25±2.23 nM for G3C-CBM. The uptake of [99mTc]G3C-CBM in A375-hPD-L1 cells (17.51±2.08 %) was approximately 6.47 folds of that in A375 cells (2.71±0.36 %) after co-incubation for 2 h. The biodistribution results showed that the radioactivity uptake in A375-hPD-L1 tumor reached the maximum (0.35±0.01 %ID/g) at 2 h post injection, and the optimum tumor/muscle ratio of 2.94±0.29 occurred at the same time. In addition, [99mTc]G3C-CBM was quickly cleared from the blood with a clearance half-life of just 119.25 min. These results indicate that [99mTc]G3C-CBM is a potential SPECT PD-L1 imaging agent and is worthy of further study.
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Affiliation(s)
- Dandan Zhu
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, China; NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Xiang Xu
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, China; NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Pei Zou
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Yaling Liu
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Hongyong Wang
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Guoqing Han
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China
| | - Chunxiong Lu
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, China; NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China.
| | - Minhao Xie
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, China; NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, China.
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Huang Y, Li C, Li Z, Wang Q, Huang S, Liu Q, Liang Y. Development and Preclinical Evaluation of [ 68Ga]BMSH as a New Potent Positron Emission Tomography Tracer for Imaging Programmed Death-Ligand 1 Expression. Pharmaceuticals (Basel) 2023; 16:1487. [PMID: 37895958 PMCID: PMC10610256 DOI: 10.3390/ph16101487] [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: 09/19/2023] [Revised: 10/07/2023] [Accepted: 10/15/2023] [Indexed: 10/29/2023] Open
Abstract
Immunotherapy targeting the programmed death-ligand 1 (PD-L1)/programmed cell death protein 1 (PD-1) pathway has shown remarkable efficacy against various cancers, but the overall response rate (ORR) is still low. PD-L1 expression in tumors may predict treatment response to immunotherapy. Indeed, ongoing clinical studies utilize a few PD-L1 radiotracers to assess PD-L1 expression as a predictive biomarker for immunotherapy. Here, we present a novel positron emission tomography (PET) radiotracer called [68Ga]BMSH, which is derived from a small molecule inhibitor specifically targeting the binding site of PD-L1. The inhibitor was modified to optimize its in vivo pharmacokinetic properties and enable chelation of 68Ga. In vitro evaluation revealed [68Ga]BMSH possessed a strong binding affinity, high specificity, and rapid internalization in PD-L1 overexpressing cells. Biodistribution studies showed that PD-L1 overexpressing tumors had an uptake of [68Ga]BMSH at 4.22 ± 0.65%ID/g in mice, while the number was 2.23 ± 0.41%ID/g in PD-L1 low-expressing tumors. Micro-PET/CT imaging of tumor-bearing mice further confirmed that, compared to [18F]FDG, [68Ga]BMSH can specifically identify tumors with varying levels of PD-L1 expression. Our findings suggest that the [68Ga]BMSH is a PD-L1 radioligand with ideal imaging properties, and its further application in the clinical screening of PD-L1 overexpressing tumors may improve ORR for immunotherapy.
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Affiliation(s)
- Yong Huang
- Department of Nuclear Medicine, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China; (Y.H.); (C.L.); (Z.L.); (Q.W.); (S.H.)
| | - Chengze Li
- Department of Nuclear Medicine, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China; (Y.H.); (C.L.); (Z.L.); (Q.W.); (S.H.)
| | - Zhongjing Li
- Department of Nuclear Medicine, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China; (Y.H.); (C.L.); (Z.L.); (Q.W.); (S.H.)
| | - Qiong Wang
- Department of Nuclear Medicine, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China; (Y.H.); (C.L.); (Z.L.); (Q.W.); (S.H.)
| | - Size Huang
- Department of Nuclear Medicine, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China; (Y.H.); (C.L.); (Z.L.); (Q.W.); (S.H.)
| | - Qi Liu
- International Cancer Center, Shenzhen University School of Medicine, Shenzhen University, Shenzhen 518057, China
- Institute of Biomedical Engineering, Shenzhen Graduate School, Peking University, Shenzhen 518055, China
| | - Ying Liang
- Department of Nuclear Medicine, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China; (Y.H.); (C.L.); (Z.L.); (Q.W.); (S.H.)
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12
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Krutzek F, Donat CK, Stadlbauer S. Exploring Hydrophilic PD-L1 Radiotracers Utilizing Phosphonic Acids: Insights into Unforeseen Pharmacokinetics. Int J Mol Sci 2023; 24:15088. [PMID: 37894769 PMCID: PMC10606431 DOI: 10.3390/ijms242015088] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/04/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023] Open
Abstract
Immune checkpoint inhibitor therapy targeting the PD-1/PD-L1 axis in cancer patients, is a promising oncological treatment. However, the number of non-responders remains high, causing a burden for the patient and the healthcare system. Consequently, a diagnostic tool to predict treatment outcomes would help with patient stratification. Molecular imaging provides said diagnostic tool by offering a whole-body quantitative assessment of PD-L1 expression, hence supporting therapy decisions. Four PD-L1 radioligand candidates containing a linker-chelator system for radiometalation, along with three hydrophilizing units-one sulfonic and two phosphonic acids-were synthesized. After labeling with 64Cu, log D7.4 values of less than -3.03 were determined and proteolytic stability confirmed over 94% intact compound after 48 h. Binding affinity was determined using two different assays, revealing high affinities up to 13 nM. µPET/CT imaging was performed in tumor-bearing mice to investigate PD-L1-specific tumor uptake and the pharmacokinetic profile of radioligands. These results yielded an unexpected in vivo distribution, such as low tumor uptake in PD-L1 positive tumors, high liver uptake, and accumulation in bone/bone marrow and potentially synovial spaces. These effects are likely caused by Ca2+-affinity and/or binding to macrophages. Despite phosphonic acids providing high water solubility, their incorporation must be carefully considered to avoid compromising the pharmacokinetic behavior of radioligands.
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Affiliation(s)
- Fabian Krutzek
- Helmholtz Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Medicinal Radiochemistry, Bautzner Landstraße 400, 01328 Dresden, Germany; (F.K.); (C.K.D.)
| | - Cornelius K. Donat
- Helmholtz Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Medicinal Radiochemistry, Bautzner Landstraße 400, 01328 Dresden, Germany; (F.K.); (C.K.D.)
| | - Sven Stadlbauer
- Helmholtz Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Department of Medicinal Radiochemistry, Bautzner Landstraße 400, 01328 Dresden, Germany; (F.K.); (C.K.D.)
- School of Science, Faculty of Chemistry and Food Chemistry, Technical University Dresden, 01069 Dresden, Germany
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