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Mo C, Sun P, Liang H, Chen Z, Wang M, Fu L, Huang S, Tang G. Synthesis and preclinical evaluation of a novel probe [ 18F]AlF-NOTA-IPB-GPC3P for PET imaging of GPC3 positive tumor. Bioorg Chem 2024; 147:107352. [PMID: 38640719 DOI: 10.1016/j.bioorg.2024.107352] [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: 02/12/2024] [Revised: 03/23/2024] [Accepted: 04/05/2024] [Indexed: 04/21/2024]
Abstract
Glypican-3 (GPC3) is markedly overexpressed in hepatocellular carcinoma (HCC) and not expressed in normal liver tissues. In this study, a novel peptide PET imaging agent ([18F]AlF-NOTA-IPB-GPC3P) was developed to target GPC3 expressed in tumors. The overall radiochemical yield of [18F]AlF-NOTA-IPB-GPC3P was 10-15 %, and its lipophilicity, expressed as the logD value at a pH of 7.4, was -1.18 ± 0.06 (n = 3). Compared to the previously reported tracer [18F]AlF-GP2633, [18F]AlF-NOTA-IPB-GPC3P exhibited higher cellular uptake (15.13 vs 5.96) and internalized rate (80.63 % vs 35.93 %) in Huh7 cells at 120 min. Micro-PET/CT and biodistribution studies further demonstrated that [18F]AlF-NOTA-IPB-GPC3P exhibited significantly increased tumor uptake and prolonged tumor residence in Huh7 tumors compared to [18F]AlF-GP2633 (4.66 ± 0.22 % ID/g vs 0.72 ± 0.09 % ID/g at 60 min, p < 0.001; 5.05 ± 0.23 % ID/g vs 0.35 ± 0.08 % ID/g at 120 min, p < 0.001, respectively). Furthermore, the tumor-to-organ ratios of [18F]AlF-NOTA-IPB-GPC3P surpassed those of [18F]AlF-GP2633. Our results support the utilization of [18F]AlF-NOTA-IPB-GPC3P as a PET imaging agent targeting the GPC3 receptor for tumor detection.
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Affiliation(s)
- Chunwei Mo
- Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, GDMPA Key Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Guangzhou, Guangdong Province 510515, China
| | - Penghui Sun
- Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, GDMPA Key Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Guangzhou, Guangdong Province 510515, China
| | - Haoran Liang
- Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, GDMPA Key Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Guangzhou, Guangdong Province 510515, China
| | - Zihao Chen
- Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, GDMPA Key Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Guangzhou, Guangdong Province 510515, China
| | - Meng Wang
- Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, GDMPA Key Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Guangzhou, Guangdong Province 510515, China
| | - Lilan Fu
- Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, GDMPA Key Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Guangzhou, Guangdong Province 510515, China
| | - Shun Huang
- Department of Nuclear Medicine, The Tenth Affiliated Hospital, Southern Medical University (Dongguan People's Hospital), Dongguan 523059, China.
| | - Ganghua Tang
- Department of Nuclear Medicine, Nanfang Hospital, Southern Medical University, GDMPA Key Laboratory for Quality Control and Evaluation of Radiopharmaceuticals, Guangzhou, Guangdong Province 510515, China.
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Bendre S, Merkens H, Kuo HT, Ng P, Wong AAWL, Lau WS, Zhang Z, Kurkowska S, Chen CC, Uribe C, Bénard F, Lin KS. Development, preclinical evaluation and preliminary dosimetry profiling of SB03178, a first-of-its-kind benzo[h]quinoline-based fibroblast activation protein-α-targeted radiotheranostic for cancer imaging and therapy. Eur J Med Chem 2024; 268:116238. [PMID: 38367492 DOI: 10.1016/j.ejmech.2024.116238] [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: 01/14/2024] [Revised: 02/03/2024] [Accepted: 02/12/2024] [Indexed: 02/19/2024]
Abstract
Fibroblast activation protein-α (FAP) is a marker of cancer-associated fibroblasts (CAFs) that constitute a significant portion of most carcinomas. Since it plays a critical role in tumor growth and metastasis, its timely detection to identify tumor lesions in early developmental stages using targeted radiopharmaceuticals has gained significant impetus. In the present work, two novel FAP-targeted precursors SB03178 and SB04033 comprising of an atypical benzo[h]quinoline construct were synthesized and either chelated to diagnostic radionuclide gallium-68 or therapeutic radionuclide lutetium-177, with ≥90% radiochemical purities and 22-76% decay-corrected radiochemical yields. natGa-labeled complexes displayed dose-dependent FAP inhibition, with binding potency of natGa-SB03178 being ∼17 times higher than natGa-SB04033. To evaluate their pharmacokinetic profiles, PET imaging and ex vivo biodistribution analyses were executed in FAP-overexpressing HEK293T:hFAP tumor-bearing mice. While both tracers displayed clear tumor visualization that was primarily FAP-arbitrated, with negligible uptake in most peripheral tissues, [68Ga]Ga-SB03178 demonstrated higher tumor uptake and superior tumor-to-background contrast ratios than [68Ga]Ga-SB04033. 177Lu-labeled SB03178 was subjected to tumor retention studies, mouse dosimetry profiling and mouse-to-human dose extrapolations also using the HEK293T:hFAP tumor model. [177Lu]Lu-SB03178 exhibited a combination of high and sustained tumor uptake, with excellent tumor-to-critical organ uptake ratios resulting in a high radiation absorbed dose to the tumor and a low estimated whole-body dose to humans. Our preliminary findings are considerably encouraging to support clinical development of [68Ga]Ga-/[177Lu]Lu-SB03178 theranostic pair for use in a vast majority of FAP-overexpressing neoplasms, particularly carcinomas.
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Affiliation(s)
- Shreya Bendre
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Helen Merkens
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Hsiou-Ting Kuo
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Pauline Ng
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Antonio A W L Wong
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Wing Sum Lau
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Zhengxing Zhang
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Sara Kurkowska
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Chao-Cheng Chen
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada
| | - Carlos Uribe
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada; Department of Molecular Imaging and Therapy, BC Cancer, Vancouver, BC, V5Z4E6, Canada; Department of Radiology, University of British Columbia, Vancouver, BC, V5Z1M9, Canada
| | - François Bénard
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada; Department of Molecular Imaging and Therapy, BC Cancer, Vancouver, BC, V5Z4E6, Canada; Department of Radiology, University of British Columbia, Vancouver, BC, V5Z1M9, Canada
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC, V5Z1L3, Canada; Department of Molecular Imaging and Therapy, BC Cancer, Vancouver, BC, V5Z4E6, Canada; Department of Radiology, University of British Columbia, Vancouver, BC, V5Z1M9, Canada.
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Escudero-Castellanos A, Kurth J, Imlimthan S, Menéndez E, Pilatis E, Moon ES, Läppchen T, Rathke H, Schwarzenböck SM, Krause BJ, Rösch F, Rominger A, Gourni E. Translational assessment of a DATA-functionalized FAP inhibitor with facile 68Ga-labeling at room temperature. Eur J Nucl Med Mol Imaging 2023; 50:3202-3213. [PMID: 37284857 PMCID: PMC10541845 DOI: 10.1007/s00259-023-06285-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/19/2023] [Indexed: 06/08/2023]
Abstract
PURPOSE The present study aims at evaluating the preclinical and the clinical performance of [68Ga]Ga-DATA5m.SA.FAPi, which has the advantage to be labeled with gallium-68 at room temperature. METHODS [68Ga]Ga-DATA5m.SA.FAPi was assessed in vitro on FAP-expressing stromal cells, followed by biodistribution and in vivo imaging on prostate and glioblastoma xenografts. Moreover, the clinical assessment of [68Ga]Ga-DATA5m.SA.FAPi was conducted on six patients with prostate cancer, aiming on investigating, biodistribution, biokinetics, and determining tumor uptake. RESULTS [68Ga]Ga-DATA5m.SA.FAPi is quantitatively prepared in an instant kit-type version at room temperature. It demonstrated high stability in human serum, affinity for FAP in the low nanomolar range, and high internalization rate when associated with CAFs. Biodistribution and PET studies in prostate and glioblastoma xenografts revealed high and specific tumor uptake. Elimination of the radiotracer mainly occurred through the urinary tract. The clinical data are in accordance with the preclinical data concerning the organ receiving the highest absorbed dose (urinary bladder wall, heart wall, spleen, and kidneys). Different to the small-animal data, uptake of [68Ga]Ga-DATA5m.SA.FAPi in tumor lesions is rapid and stable and tumor-to-organ and tumor-to-blood uptake ratios are high. CONCLUSION The radiochemical, preclinical, and clinical data obtained in this study strongly support further development of [68Ga]Ga-DATA5m.SA.FAPi as a diagnostic tool for FAP imaging.
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Affiliation(s)
| | - Jens Kurth
- Department of Nuclear Medicine, Rostock University Medical Centre, Rostock, Germany
| | - Surachet Imlimthan
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Elena Menéndez
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Eirinaios Pilatis
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Euy Sung Moon
- Department of Chemistry-TRIGA site, Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - Tilman Läppchen
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Hendrik Rathke
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | | | - Bernd J Krause
- Department of Nuclear Medicine, Rostock University Medical Centre, Rostock, Germany
| | - Frank Rösch
- Department of Chemistry-TRIGA site, Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - Axel Rominger
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Eleni Gourni
- Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
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Lai C, Cao R, Li R, He C, Wang X, Shi H, Qu C, Qian K, Song S, Chen WH, Cheng Z. Fibroblast Activation Protein Targeting Probe with Gly-Pro Sequence for PET of Glioblastoma. Mol Pharm 2023; 20:4120-4128. [PMID: 37487027 DOI: 10.1021/acs.molpharmaceut.3c00248] [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: 07/26/2023]
Abstract
As an important cancer-associated fibroblast-specific biomarker, fibroblast activation protein (FAP) has become an attractive target for tumor diagnosis and treatment. However, most FAP-based radiotracers showed inadequate uptake and short retention in tumors. In this study, we designed and synthesized a novel FAP ligand (DOTA-GPFAPI-04) through assembling three functional moieties: a quinoline-based FAP inhibitor for specifically targeting FAP, a FAP substrate Gly-Pro as a linker for increasing the FAP protein interaction, and a 2,2',2″,2‴-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA) chelator for radiolabeling with different radionuclides. The FAP targeting ability of DOTA-GPFAPI-04 was investigated by molecular docking studies. DOTA-GPFAPI-04 was then radiolabeled with 68Ga to give [68Ga]Ga-DOTA-GPFAPI-04 for positron emission tomography (PET) imaging of glioblastoma. [68Ga]Ga-DOTA-GPFAPI-04 exhibited a purity of >98% and high stability analyzed by radio-HPLC in saline and mouse serum. Cell uptake studies demonstrated the targeting specificity of the probe. Further in vivo pharmacokinetic studies in normal mice demonstrated the quick clearance of the probe. Moreover, compared with the widely studied [68Ga]Ga-FAPI-04, [68Ga]Ga-DOTA-GPFAPI-04 showed much higher U87MG tumor uptake values (4.467 ± 0.379 for [68Ga]Ga-DOTA-GPFAPI-04 and 1.267 ± 0.208% ID/g for [68Ga]Ga-FAPI-04 at 0.5 h post-injection, respectively). The area under the curve based on time-activity curve (TAC) analysis for tumor radioactivity in small animal models was 422.5 for [68Ga]Ga-DOTA-GPFAPI-04 and 98.14 for [68Ga]Ga-FAPI-04, respectively, demonstrating that the former had longer tumor retention time. The tumor-to-muscle (T/M) ratio for [68Ga]Ga-DOTA-GPFAPI-04 reached 9.15 in a U87MG xenograft animal model. PET imaging and blocking assays showed that [68Ga]Ga-DOTA-GPFAPI-04 had specific tumor uptake. In summary, this study demonstrates the successful synthesis and evaluation of a novel FAPI targeting probe, [68Ga]Ga-DOTA-GPFAPI-04, with a Gly-Pro sequence. It shows favorable in vivo glioblastoma imaging properties and relatively long tumor retention, highlighting DOTA-GPFAPI-04 as a promising molecular scaffold for developing FAP targeting tumor theranostic agents.
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Affiliation(s)
- Chaoquan Lai
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
- State Key Laboratory of Drug Research, Molecular Imaging Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Rui Cao
- State Key Laboratory of Drug Research, Molecular Imaging Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Renda Li
- State Key Laboratory of Drug Research, Molecular Imaging Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Chunfeng He
- State Key Laboratory of Drug Research, Molecular Imaging Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xiao Wang
- Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Shanghai 200032, China
| | - Hui Shi
- State Key Laboratory of Drug Research, Molecular Imaging Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Chunrong Qu
- State Key Laboratory of Drug Research, Molecular Imaging Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Kun Qian
- State Key Laboratory of Drug Research, Molecular Imaging Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Shaoli Song
- Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Shanghai 200032, China
| | - Wen-Hua Chen
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
| | - Zhen Cheng
- State Key Laboratory of Drug Research, Molecular Imaging Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- Shandong Laboratory of Yantai Drug Discovery, Bohai Rim Advanced Research Institute for Drug Discovery, Yantai, Shandong 264117, China
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Chandekar KR, Prashanth A, Vinjamuri S, Kumar R. FAPI PET/CT Imaging-An Updated Review. Diagnostics (Basel) 2023; 13:2018. [PMID: 37370912 DOI: 10.3390/diagnostics13122018] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023] Open
Abstract
Despite revolutionizing the field of oncological imaging, Positron Emission Tomography (PET) with [18F]Fluorodeoxyglucose (FDG) as its workhorse is limited by a lack of specificity and low sensitivity in certain tumor subtypes. Fibroblast activation protein (FAP), a type II transmembrane glycoprotein, is expressed by cancer-associated fibroblasts (CAFs) that form a major component of the tumor stroma. FAP holds the promise to be a pan-cancer target, owing to its selective over-expression in a vast majority of neoplasms, particularly epithelial cancers. Several radiolabeled FAP inhibitors (FAPI) have been developed for molecular imaging and potential theranostic applications. Preliminary data on FAPI PET/CT remains encouraging, with extensive multi-disciplinary clinical research currently underway. This review summarizes the existing literature on FAPI PET/CT imaging with an emphasis on diagnostic applications, comparison with FDG, pitfalls, and future directions.
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Affiliation(s)
- Kunal Ramesh Chandekar
- Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Arun Prashanth
- Department of Nuclear Medicine, MIOT International Hospital, Chennai 600089, India
| | - Sobhan Vinjamuri
- Department of Nuclear Medicine, Royal Liverpool and Broadgreen University Hospital, Liverpool L7-8YE, UK
| | - Rakesh Kumar
- Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi 110029, India
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Bendre S, Kuo HT, Merkens H, Zhang Z, Wong AAWL, Bénard F, Lin KS. Synthesis and Preclinical Evaluation of Novel 68Ga-Labeled ( R)-Pyrrolidin-2-yl-boronic Acid-Based PET Tracers for Fibroblast Activation Protein-Targeted Cancer Imaging. Pharmaceuticals (Basel) 2023; 16:798. [PMID: 37375746 DOI: 10.3390/ph16060798] [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: 05/03/2023] [Revised: 05/20/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
Fibroblast activation protein (FAP) is a membrane-tethered serine protease overexpressed in the reactive stromal fibroblasts of >90% human carcinomas, which makes it a promising target for developing radiopharmaceuticals for the imaging and therapy of carcinomas. Here, we synthesized two novel (R)-pyrrolidin-2-yl-boronic acid-based FAP-targeted ligands: SB02055 (DOTA-conjugated (R)-(1-((6-(3-(piperazin-1-yl)propoxy)quinoline-4-carbonyl)glycyl)pyrrolidin-2-yl)boronic acid) and SB04028 (DOTA-conjugated ((R)-1-((6-(3-(piperazin-1-yl)propoxy)quinoline-4-carbonyl)-D-alanyl)pyrrolidin-2-yl)boronic acid). natGa- and 68Ga-complexes of both ligands were evaluated in preclinical studies and compared to previously reported natGa/68Ga-complexed PNT6555. Enzymatic assays showed that FAP binding affinities (IC50) of natGa-SB02055, natGa-SB04028 and natGa-PNT6555 were 0.41 ± 0.06, 13.9 ± 1.29 and 78.1 ± 4.59 nM, respectively. PET imaging and biodistribution studies in HEK293T:hFAP tumor-bearing mice showed that while [68Ga]Ga-SB02055 presented with a nominal tumor uptake (1.08 ± 0.37 %ID/g), [68Ga]Ga-SB04028 demonstrated clear tumor visualization with ~1.5-fold higher tumor uptake (10.1 ± 0.42 %ID/g) compared to [68Ga]Ga-PNT6555 (6.38 ± 0.45 %ID/g). High accumulation in the bladder indicated renal excretion of all three tracers. [68Ga]Ga-SB04028 displayed a low background level uptake in most normal organs, and comparable to [68Ga]Ga-PNT6555. However, since its tumor uptake was considerably higher than [68Ga]Ga-PNT6555, the corresponding tumor-to-organ uptake ratios for [68Ga]Ga-SB04028 were also significantly greater than [68Ga]Ga-PNT6555. Our data demonstrate that (R)-(((quinoline-4-carbonyl)-d-alanyl)pyrrolidin-2-yl)boronic acid is a promising pharmacophore for the design of FAP-targeted radiopharmaceuticals for cancer imaging and radioligand therapy.
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Affiliation(s)
- Shreya Bendre
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - Hsiou-Ting Kuo
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - Helen Merkens
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - Zhengxing Zhang
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - Antonio A W L Wong
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - François Bénard
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
- Department of Functional Imaging, BC Cancer Research Institute, Vancouver, BC V5Z 4E6, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
- Department of Functional Imaging, BC Cancer Research Institute, Vancouver, BC V5Z 4E6, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
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DiMagno SG, Babich JW. Advanced Fibroblast Activation Protein-Ligand Developments: FAP Imaging Agents: A Review of the Structural Requirements. PET Clin 2023:S1556-8598(23)00028-7. [PMID: 37117123 DOI: 10.1016/j.cpet.2023.03.002] [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: 04/30/2023]
Abstract
Fibroblast activation protein-α (FAP) has attracted increasing attention as a selective marker of cancer-associated fibroblasts (CAFs) and more broadly, of activated fibroblasts in tissues undergoing remodeling of their ECM due to chronic inflammation, fibrosis, or wound healing. Since FAP is critical to the initiation of metastatic growth, its expression will serve as a molecular marker to detect tumors at an earlier stage of development compared to currently available methods. The design of high affinity small molecule FAP inhibitor will allow for noninvasive imaging of activated fibroblast in cancer patients. Small molecule inhibitors of FAP are being developed for targeted radiotherapy of tumors.
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Affiliation(s)
- Stephen G DiMagno
- Ratio Therapeutics, Inc., One Design Center Place, Suite# 19-601, Boston, MA 02210, USA
| | - John W Babich
- Ratio Therapeutics, Inc., One Design Center Place, Suite# 19-601, Boston, MA 02210, USA.
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Bendre S, Zhang Z, Colpo N, Zeisler J, Wong AAWL, Bénard F, Lin KS. Synthesis and Evaluation of 68Ga-Labeled (2 S,4 S)-4-Fluoropyrrolidine-2-Carbonitrile and (4 R)-Thiazolidine-4-Carbonitrile Derivatives as Novel Fibroblast Activation Protein-Targeted PET Tracers for Cancer Imaging. Molecules 2023; 28:molecules28083481. [PMID: 37110717 PMCID: PMC10145249 DOI: 10.3390/molecules28083481] [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: 03/18/2023] [Revised: 04/08/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
Fibroblast activation protein α (FAP-α) is a cell-surface protein overexpressed on cancer-associated fibroblasts that constitute a substantial component of tumor stroma and drive tumorigenesis. FAP is minimally expressed by most healthy tissues, including normal fibroblasts. This makes it a promising pan-cancer diagnostic and therapeutic target. In the present study, we synthesized two novel tracers, [68Ga]Ga-SB03045 and [68Ga]Ga-SB03058, bearing a (2S,4S)-4-fluoropyrrolidine-2-carbonitrile or a (4R)-thiazolidine-4-carbonitrile pharmacophore, respectively. [68Ga]Ga-SB03045 and [68Ga]Ga-SB03058 were evaluated for their FAP-targeting capabilities using substrate-based in vitro binding assays, and in PET/CT imaging and ex vivo biodistribution studies in an HEK293T:hFAP tumor xenograft mouse model. The IC50 values of natGa-SB03045 (1.59 ± 0.45 nM) and natGa-SB03058 (0.68 ± 0.09 nM) were found to be lower than those of the clinically validated natGa-FAPI-04 (4.11 ± 1.42 nM). Contrary to the results obtained in the FAP-binding assay, [68Ga]Ga-SB03058 demonstrated a ~1.5 fold lower tumor uptake than that of [68Ga]Ga-FAPI-04 (7.93 ± 1.33 vs. 11.90 ± 2.17 %ID/g), whereas [68Ga]Ga-SB03045 (11.8 ± 2.35 %ID/g) exhibited a tumor uptake comparable to that of [68Ga]Ga-FAPI-04. Thus, our data suggest that the (2S,4S)-4-fluoropyrrolidine-2-carbonitrile scaffold holds potential as a promising pharmacophore for the design of FAP-targeted radioligands for cancer diagnosis and therapy.
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Affiliation(s)
- Shreya Bendre
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - Zhengxing Zhang
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - Nadine Colpo
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - Jutta Zeisler
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - Antonio A W L Wong
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
| | - François Bénard
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
- Department of Functional Imaging, BC Cancer, Vancouver, BC V5Z 4E6, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada
- Department of Functional Imaging, BC Cancer, Vancouver, BC V5Z 4E6, Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
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Albumin-Mediated Size Exclusion Chromatography: The Apparent Molecular Weight of PSMA Radioligands as Novel Parameter to Estimate Their Blood Clearance Kinetics. Pharmaceuticals (Basel) 2022; 15:ph15091161. [PMID: 36145382 PMCID: PMC9500755 DOI: 10.3390/ph15091161] [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: 08/11/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 11/17/2022] Open
Abstract
A meticulously adjusted pharmacokinetic profile and especially fine-tuned blood clearance kinetics are key characteristics of therapeutic radiopharmaceuticals. We, therefore, aimed to develop a method that allowed the estimation of blood clearance kinetics in vitro. For this purpose, 177Lu-labeled PSMA radioligands were subjected to a SEC column with human serum albumin (HSA) dissolved in a mobile phase. The HSA-mediated retention time of each PSMA ligand generated by this novel 'albumin-mediated size exclusion chromatography' (AMSEC) was converted to a ligand-specific apparent molecular weight (MWapp), and a normalization accounting for unspecific interactions between individual radioligands and the SEC column matrix was applied. The resulting normalized MWapp,norm. could serve to estimate the blood clearance of renally excreted radioligands by means of their influence on the highly size-selective process of glomerular filtration (GF). Based on the correlation between MW and the glomerular sieving coefficients (GSCs) of a set of plasma proteins, GSCcalc values were calculated to assess the relative differences in the expected GF/blood clearance kinetics in vivo and to select lead candidates among the evaluated radioligands. Significant differences in the MWapp,norm. and GSCcalc values, even for stereoisomers, were found, indicating that AMSEC might be a valuable and high-resolution tool for the preclinical selection of therapeutic lead compounds for clinical translation.
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10
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Meng L, Fang J, Zhao L, Wang T, Yuan P, Zhao Z, Zhuang R, Lin Q, Chen H, Chen X, Zhang X, Guo Z. Rational Design and Pharmacomodulation of Protein-Binding Theranostic Radioligands for Targeting the Fibroblast Activation Protein. J Med Chem 2022; 65:8245-8257. [PMID: 35658448 DOI: 10.1021/acs.jmedchem.1c02162] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The fibroblast activation protein (FAP), overexpressed on cancer-associated fibroblasts (CAFs), has become a valuable target for tumor diagnosis and therapy. However, most FAP-based radioligands show insufficient tumor uptake and retention. In this study, three novel albumin-binding FAP ligands (denoted as FSDD0I, FSDD1I, and FSDD3I) were labeled with 68Ga and 177Lu to overcome these limitations. Cell-based studies and molecular docking assays were performed to identify the specificity and protein-binding properties for FAP. Positron emission tomography (PET) scans in human hepatocellular carcinoma patient-derived xenografts (HCC-PDXs) animal models revealed longer blood retention of 68Ga-FSDD0I than 68Ga-FAPI-04, 68Ga-FSDD1I, and 68Ga-FSDD3I. Remarkably, 68Ga-FSDD3I had prominent tumor-to-nontarget (T/NT) ratios. The prominent tumor retention properties of 177Lu-FSDD0I in single photon emission computed tomography (SPECT) imaging and biodistribution studies were demonstrated. In summary, this study reports a proof-of-concept study of albumin-binding radioligands for FAP-targeted imaging and targeted radionuclide therapy (TRT).
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Affiliation(s)
- Lingxin Meng
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Jianyang Fang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Liang Zhao
- Department of Nuclear Medicine & Minnan PET Center, The First Affiliated Hospital of Xiamen University, Xiamen 361003, China.,Department of Radiation Oncology, The First Affiliated Hospital of Xiamen University, Xiamen 361003, China
| | - Tingting Wang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Pu Yuan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Zuoquan Zhao
- Department of Nuclear Medicine, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences, Beijing 100037, China
| | - Rongqiang Zhuang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Qin Lin
- Department of Radiation Oncology, The First Affiliated Hospital of Xiamen University, Xiamen 361003, China
| | - Haojun Chen
- Department of Nuclear Medicine & Minnan PET Center, The First Affiliated Hospital of Xiamen University, Xiamen 361003, China
| | - Xiaoyuan Chen
- Departments of Diagnostic Radiology, Surgery, Chemical and Biomolecular Engineering, and Biomedical Engineering, Yong Loo Lin School of Medicine and Faculty of Engineering, National University of Singapore, Singapore 119074, Singapore.,Clinical Imaging Research Centre, Centre for Translational Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore.,Nanomedicine Translational Research Program, NUS Center for Nanomedicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Xianzhong Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Zhide Guo
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
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11
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Xu M, Zhang P, Ding J, Chen J, Huo L, Liu Z. Albumin Binder-Conjugated Fibroblast Activation Protein Inhibitor Radiopharmaceuticals for Cancer Therapy. J Nucl Med 2022; 63:952-958. [PMID: 34593598 PMCID: PMC9157728 DOI: 10.2967/jnumed.121.262533] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/25/2021] [Indexed: 11/16/2022] Open
Abstract
Fibroblast activation protein (FAP) has become an attractive target for diagnosis and therapy, and a series of FAP inhibitor (FAPI)-based radiotracers has been developed and had excellent performance for diagnosis outcomes in clinical applications. Yet, their fast clearance and insufficient tumor retention have hampered their further clinical application in cancer treatment. In this study, we developed 2 albumin binder-conjugated FAPI radiotracers, TEFAPI-06 and TEFAPI-07. They were derived from FAPI-04 and were optimized by conjugating 2 types of well-studied albumin binders, 4-(p-iodophenyl) butyric acid moiety (TEFAPI-06) and truncated Evans blue moiety (TEFAPI-07), to try to overcome the above limitations at the expense of prolonging the blood circulation. Methods: TEFAPI-06 and TEFAPI-07 were synthesized and labeled with 68Ga, 86Y, and 177Lu successfully. A series of cell assays was performed to identify the binding affinity and FAP specificity in vitro. PET imaging, SPECT imaging, and biodistribution studies were performed to evaluate the pharmacokinetics in pancreatic cancer patient-derived xenograft (PDX) animal models. The cancer treatment efficacy of 177Lu-TEFAPI-06 and 177Lu-TEFAPI-07 were evaluated in pancreatic cancer PDX-bearing mice. Results: The binding affinities (dissociation constants) to FAP of 68Ga-TEFAPI-06 and 68Ga-TEFAPI-07 were 10.16 ± 2.56 nM and 7.81 ± 2.28 nM, respectively, which were comparable with that of 68Ga-FAPI-04. Comparative PET imaging of HT-1080-FAP and HT-1080 tumor-bearing mice and a blocking study showed the FAP-targeting ability in vivo of these 2 tracers. Compared with 177Lu-FAPI-04, PET imaging, SPECT imaging, and biodistribution studies of TEFAPI-06 and TEFAPI-07 demonstrated their remarkably enhanced tumor accumulation and retention, respectively. Notable tumor growth inhibition by 177Lu-TEFAPI-06 and 177Lu-TEFAPI-07 were observed, whereas the control group and the group treated by 177Lu-FAPI-04 showed a slight therapeutic effect. Conclusion: Two albumin binder-conjugated FAPI radiopharmaceuticals have been developed and evaluated in vitro and in vivo. Significantly improved tumor uptake and retention were observed, compared with the original FAPI tracer. Both 177Lu-TEFAPI-06 and 177Lu-TEFAPI-07 showed remarkable growth inhibition of PDX tumors, whereas the side effects were almost negligible, demonstrating that these radiopharmaceuticals are promising for further clinical translational studies.
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Affiliation(s)
- Mengxin Xu
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Pu Zhang
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Jie Ding
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China; and
| | - Junyi Chen
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Li Huo
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China; and
| | - Zhibo Liu
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China;
- Peking University-Tsinghua University Center for Life Sciences, Beijing, China
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12
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Zboralski D, Hoehne A, Bredenbeck A, Schumann A, Nguyen M, Schneider E, Ungewiss J, Paschke M, Haase C, von Hacht JL, Kwan T, Lin KK, Lenore J, Harding TC, Xiao J, Simmons AD, Mohan AM, Beindorff N, Reineke U, Smerling C, Osterkamp F. Preclinical evaluation of FAP-2286 for fibroblast activation protein targeted radionuclide imaging and therapy. Eur J Nucl Med Mol Imaging 2022; 49:3651-3667. [PMID: 35608703 PMCID: PMC9399058 DOI: 10.1007/s00259-022-05842-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/10/2022] [Indexed: 12/18/2022]
Abstract
PURPOSE Fibroblast activation protein (FAP) is a membrane-bound protease that has limited expression in normal adult tissues but is highly expressed in the tumor microenvironment of many solid cancers. FAP-2286 is a FAP-binding peptide coupled to a radionuclide chelator that is currently being investigated in patients as an imaging and therapeutic agent. The potency, selectivity, and efficacy of FAP-2286 were evaluated in preclinical studies. METHODS FAP expression analysis was performed by immunohistochemistry and autoradiography on primary human cancer specimens. FAP-2286 was assessed in biochemical and cellular assays and in in vivo imaging and efficacy studies, and was further evaluated against FAPI-46, a small molecule-based FAP-targeting agent. RESULTS Immunohistochemistry confirmed elevated levels of FAP expression in multiple tumor types including pancreatic, breast, and sarcoma, which correlated with FAP binding by FAP-2286 autoradiography. FAP-2286 and its metal complexes demonstrated high affinity to FAP recombinant protein and cell surface FAP expressed on fibroblasts. Biodistribution studies in mice showed rapid and persistent uptake of 68Ga-FAP-2286, 111In-FAP-2286, and 177Lu-FAP-2286 in FAP-positive tumors, with renal clearance and minimal uptake in normal tissues. 177Lu-FAP-2286 exhibited antitumor activity in FAP-expressing HEK293 tumors and sarcoma patient-derived xenografts, with no significant weight loss. In addition, FAP-2286 maintained longer tumor retention and suppression in comparison to FAPI-46. CONCLUSION In preclinical models, radiolabeled FAP-2286 demonstrated high tumor uptake and retention, as well as potent efficacy in FAP-positive tumors. These results support clinical development of 68Ga-FAP-2286 for imaging and 177Lu-FAP-2286 for therapeutic use in a broad spectrum of FAP-positive tumors.
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Affiliation(s)
- Dirk Zboralski
- 3B Pharmaceuticals GmbH, Magnusstraße 11, 12489, Berlin, Germany.
| | - Aileen Hoehne
- 3B Pharmaceuticals GmbH, Magnusstraße 11, 12489, Berlin, Germany
| | - Anne Bredenbeck
- 3B Pharmaceuticals GmbH, Magnusstraße 11, 12489, Berlin, Germany
| | - Anne Schumann
- 3B Pharmaceuticals GmbH, Magnusstraße 11, 12489, Berlin, Germany
| | | | | | - Jan Ungewiss
- 3B Pharmaceuticals GmbH, Magnusstraße 11, 12489, Berlin, Germany
| | - Matthias Paschke
- 3B Pharmaceuticals GmbH, Magnusstraße 11, 12489, Berlin, Germany
| | - Christian Haase
- 3B Pharmaceuticals GmbH, Magnusstraße 11, 12489, Berlin, Germany
| | - Jan L von Hacht
- 3B Pharmaceuticals GmbH, Magnusstraße 11, 12489, Berlin, Germany
| | | | | | | | | | - Jim Xiao
- Clovis Oncology, Inc, Boulder, CO, USA
| | | | - Ajay-Mohan Mohan
- Berlin Experimental Radionuclide Imaging Center, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Nicola Beindorff
- Berlin Experimental Radionuclide Imaging Center, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ulrich Reineke
- 3B Pharmaceuticals GmbH, Magnusstraße 11, 12489, Berlin, Germany
| | | | - Frank Osterkamp
- 3B Pharmaceuticals GmbH, Magnusstraße 11, 12489, Berlin, Germany
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13
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Lindner T, Giesel FL, Kratochwil C, Serfling SE. Radioligands Targeting Fibroblast Activation Protein (FAP). Cancers (Basel) 2021; 13:cancers13225744. [PMID: 34830898 PMCID: PMC8616197 DOI: 10.3390/cancers13225744] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/11/2021] [Accepted: 11/11/2021] [Indexed: 01/07/2023] Open
Abstract
Simple Summary FAP-targeted radiotracers, recently introduced in cancer treatment, accumulate in Cancer-Associated Fibroblasts (CAFs). CAFs are present in tumor lesions but do not correspond to genuine cancer cells, although they behave in an abnormal and disease-promoting manner. One of their characteristic features, the expression of the surface protein FAP, can be utilized to discriminate between cancerous and healthy tissues. By the choice of an appropriate radionuclide, FAP-targeted tracers can be used for imaging or therapy in many cancer types. Therefore, the first successful application of FAP-targeted imaging has led to an enormous and growing interest in nuclear medicine and radiopharmacy. Abstract Targeting fibroblast activation protein (FAP) in cancer-associated fibroblasts (CAFs) has attracted significant attention in nuclear medicine. Since these cells are present in most cancerous tissues and FAP is rarely expressed in healthy tissues, anti-FAP tracers have a potential as pan-tumor agents. Compared to the standard tumor tracer [18F]FDG, these tracers show better tumor-to-background ratios (TBR) in many indications. Unlike [18F]FDG, FAP-targeted tracers do not require exhausting preparations, such as dietary restrictions on the part of the patient, and offer the possibility of radioligand therapy (RLT) in a theragnostic approach. Although a radiolabeled antibody was clinically investigated as early as the 1990s, the breakthrough event for FAP-targeting in nuclear medicine was the introduction and clinical application of the so-called FAPI-tracers in 2018. From then, the development and application of FAP-targeted tracers became hot topics for the radiopharmaceutical and nuclear medicine community, and attracted the interest of pharmaceutical companies. The aim of this review is to provide a comprehensive overview of the development of FAP-targeted radiopharmaceuticals and their application in nuclear medicine.
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Affiliation(s)
- Thomas Lindner
- Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany;
- Correspondence:
| | - Frederik L. Giesel
- Department of Nuclear Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany;
| | - Clemens Kratochwil
- Department of Nuclear Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany;
| | - Sebastian E. Serfling
- Department of Nuclear Medicine, University Hospital Würzburg, 97080 Würzburg, Germany;
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14
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Imlimthan S, Moon ES, Rathke H, Afshar-Oromieh A, Rösch F, Rominger A, Gourni E. New Frontiers in Cancer Imaging and Therapy Based on Radiolabeled Fibroblast Activation Protein Inhibitors: A Rational Review and Current Progress. Pharmaceuticals (Basel) 2021; 14:1023. [PMID: 34681246 PMCID: PMC8540221 DOI: 10.3390/ph14101023] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/29/2021] [Accepted: 09/29/2021] [Indexed: 12/13/2022] Open
Abstract
Over the past decade, the tumor microenvironment (TME) has become a new paradigm of cancer diagnosis and therapy due to its unique biological features, mainly the interconnection between cancer and stromal cells. Within the TME, cancer-associated fibroblasts (CAFs) demonstrate as one of the most critical stromal cells that regulate tumor cell growth, progression, immunosuppression, and metastasis. CAFs are identified by various biomarkers that are expressed on their surfaces, such as fibroblast activation protein (FAP), which could be utilized as a useful target for diagnostic imaging and treatment. One of the advantages of targeting FAP-expressing CAFs is the absence of FAP expression in quiescent fibroblasts, leading to a controlled targetability of diagnostic and therapeutic compounds to the malignant tumor stromal area using radiolabeled FAP-based ligands. FAP-based radiopharmaceuticals have been investigated strenuously for the visualization of malignancies and delivery of theranostic radiopharmaceuticals to the TME. This review provides an overview of the state of the art in TME compositions, particularly CAFs and FAP, and their roles in cancer biology. Moreover, relevant reports on radiolabeled FAP inhibitors until the year 2021 are highlighted-as well as the current limitations, challenges, and requirements for those radiolabeled FAP inhibitors in clinical translation.
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Affiliation(s)
- Surachet Imlimthan
- Department of Nuclear Medicine, the Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; (S.I.); (H.R.); (A.A.-O.); (A.R.)
| | - Euy Sung Moon
- Department of Chemistry—TRIGA Site, Johannes Gutenberg—University Mainz, 55128 Mainz, Germany; (E.S.M.); (F.R.)
| | - Hendrik Rathke
- Department of Nuclear Medicine, the Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; (S.I.); (H.R.); (A.A.-O.); (A.R.)
| | - Ali Afshar-Oromieh
- Department of Nuclear Medicine, the Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; (S.I.); (H.R.); (A.A.-O.); (A.R.)
| | - Frank Rösch
- Department of Chemistry—TRIGA Site, Johannes Gutenberg—University Mainz, 55128 Mainz, Germany; (E.S.M.); (F.R.)
| | - Axel Rominger
- Department of Nuclear Medicine, the Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; (S.I.); (H.R.); (A.A.-O.); (A.R.)
| | - Eleni Gourni
- Department of Nuclear Medicine, the Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; (S.I.); (H.R.); (A.A.-O.); (A.R.)
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15
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Lin JJ, Chuang CP, Lin JY, Huang FT, Huang CW. Rational Design, Pharmacomodulation, and Synthesis of [ 68Ga]Ga-Alb-FAPtp-01, a Selective Tumor-Associated Fibroblast Activation Protein Tracer for PET Imaging of Glioma. ACS Sens 2021; 6:3424-3435. [PMID: 34415143 DOI: 10.1021/acssensors.1c01316] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Dynamic changes in the tumor-associated fibroblast activation protein (FAP) expression in tumors of different stages may be helpful for prognostic evaluation and treatment response monitoring, making this protein a promising surveillance biomarker for timely diagnosis of malignant tumors and effective planning of patient care. To prospectively verify the diagnostic efficacy value of the developed FAP tracers, [68Ga]Ga-FAPtp and [68Ga]Ga-Alb-FAPtp-01, dynamic/static positron emission tomography (PET)/computed tomography scans were acquired for tumor-targeting studies in vivo and in comparison with the well-established clinically used tracer [68Ga]Ga-FAPI-04. The optimized rationally designed FAP-targeting PET tracer, [68Ga]Ga-Alb-FAPtp-01, with albumin-binding capability demonstrated prominent tumor uptake over time. The mean standard uptake value (SUV) and the tumor/muscle (T/M) ratio were as high as 1.775 ± 0.179 SUV and T/M = 5.9, 1.533 ± 0.222 SUV and T/M = 6.7, and 1.425 ± 0.204 SUV and T/M = 9.5, respectively, at 1, 2, and 3 h. Its improved tumor uptake and pharmacokinetics suggest that the [68Ga]Ga-Alb-FAPtp-01 tracer can noninvasively detect FAP activation in vivo, permitting a precise definition of its roles in tumors of different stages and yielding insights regarding FAP-targeted radiotherapeutic strategies at the molecular level.
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Affiliation(s)
- Jia-Jia Lin
- Center for Advanced Molecular Imaging and Translation (CAMIT), Department of Medical Research, Chang Gung Memorial Hospital, Linkou, Taoyuan 333, Taiwan
- Department of Nuclear Medicine, New Taipei Municipal TuCheng Hospital, New Taipei City 236, Taiwan
| | - Chia-Pao Chuang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei 106, Taiwan
| | - Jia-Yu Lin
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei 106, Taiwan
| | - Feng-Ting Huang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei 106, Taiwan
| | - Chiun-Wei Huang
- Center for Advanced Molecular Imaging and Translation (CAMIT), Department of Medical Research, Chang Gung Memorial Hospital, Linkou, Taoyuan 333, Taiwan
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