Abstract
Introduction
Radiopharmaceuticals that target cancer-associated fibroblasts (CAFs) have become an increasingly attractive strategy for cancer theranostics. Recently, a series of fibroblast activation protein inhibitor (FAPI)-based radiopharmaceuticals have been successfully applied to the diagnosis of a variety of cancers and exhibited excellent tumor selectivity. Nevertheless, CAF-targeted radionuclide therapy encounters difficulties in cancer treatment, as the tumor uptake and retention of FAPIs are insufficient. To meet this challenge, we tried to conjugate albumin-binding moiety to FAPI molecule for prolonged circulation that may increase the accumulation and retention of radiopharmaceuticals in tumor.
Methods
Two fatty acids, lauric acid (C12) and palmitic acid (C16), were conjugated to FAPI-04 to give two albumin-binding FAPI radiopharmaceuticals, denoted as FAPI-C12 and FAPI-C16, respectively. They had been radiolabeled with gallium-68, yttrium-86, and lutecium-177 for stability study, binding affinity assay, PET and SPECT imaging, biodistribution, and radionuclide therapy study to systematically evaluate their potential for CAF-targeted radionuclide therapy.
Results
FAPI-C12 and FAPI-C16 showed high binding affinity to FAP with the IC50 of 6.80 ± 0.58 nM and 5.06 ± 0.69 nM, respectively. They were stable in both saline and plasma. The tumor uptake of [68Ga]Ga-FAPI-04 decreased by 56.9% until 30 h after treated with FAPI-C16 before, and the uptakes of [86Y]Y-FAPI-C12 and [86Y]Y-FAPI-C16 in HT-1080-FAP tumor were both much higher than that of HT-1080-Vehicle tumor which identified the high FAP specific of these two radiopharmaceuticals. Both FAPI-C12 and FAPI-C16 showed notably longer circulation and significantly enhanced tumor uptake than those of FAPI-04. [177Lu]Lu-FAPI-C16 had the higher tumor uptake at both 24 h (11.22 ± 1.18%IA/g) and 72 h (6.50 ± 1.19%IA/g) than that of [177Lu]Lu-FAPI-C12 (24 h, 7.54 ± 0.97%IA/g; 72 h, 2.62 ± 0.65%IA/g); both of them were much higher than [177Lu]Lu-FAPI-04 with the value of 1.24 ± 0.54%IA/g at 24 h after injection. Significant tumor volume inhibition of [177Lu]Lu-FAPI-C16 at the high activity of 29.6 MBq was observed, and the median survival was 28 days which was much longer than that of the [177Lu]Lu-FAPI-04 treated group of which the median survival was only 10 days.
Conclusion
This proof-of-concept study validates the hypothesis that conjugation of albumin binders may shift the pharmacokinetics and enhance the tumor uptake of FAPI-based radiopharmaceuticals. This could be a general strategy to transform the diagnostic FAP-targeted radiopharmaceuticals into their therapeutic pairs.
Similar content being viewed by others
References
Xouri G, Christian S. Origin and function of tumor stroma fibroblasts. Semin Cell Dev Biol. 2010;21:40–6. https://doi.org/10.1016/j.semcdb.2009.11.017.
Eble JA, Niland S. The extracellular matrix in tumor progression and metastasis. Clin Exp Metastasis. 2019;36:171–98. https://doi.org/10.1007/s10585-019-09966-1.
Valkenburg KC, de Groot AE, Pienta KJ. Targeting the tumour stroma to improve cancer therapy. Nat Rev Clin Oncol. 2018;15:366–81. https://doi.org/10.1038/s41571-018-0007-1.
Östman A, Augsten M. Cancer-associated fibroblasts and tumor growth-bystanders turning into key players. Curr Opin Genet Dev. 2009;19:67–73. https://doi.org/10.1016/j.gde.2009.01.003.
Sahai E, Astsaturov I, Cukierman E, Denardo DG, Werb Z. A framework for advancing our understanding of cancer-associated fibroblasts. Nat Rev Cancer. 2020;20:1–13. https://doi.org/10.1038/s41568-019-0238-1.
Cirri P, Chiarugi P. Cancer associated fibroblasts: the dark side of the coin. Am J Cancer Res. 2011;1:482–97. https://doi.org/10.1016/B978-0-12-385524-4.00004-0.
Chen X, Song E. Turning foes to friends: targeting cancer-associated fibroblasts. Nat Rev Drug Discovery. 2019;18:99–115. https://doi.org/10.1038/s41573-018-0004-1.
Koustoulidou S, Hoorens M, Dalm SU, Mahajan S, Jong MD. Cancer-associated fibroblasts as players in cancer development and progression and their role in targeted radionuclide imaging and therapy. Cancers. 2021;13:1100. https://doi.org/10.3390/cancers13051100.
Park JE, Lenter MC, Zimmermann RN, Garin-Chesa P, Old LJ, Rettig WJ. Fibroblast activation protein, a dual specificity serine protease expressed in reactive human tumor stromal fibroblasts. J Cell Biochem. 1999;274:36505–12. https://doi.org/10.1074/jbc.274.51.36505.
Altmann A, Haberkorn U, Siveke J. The latest developments in imaging of fibroblast activation protein. J Nucl Med. 2021;62:160–7. https://doi.org/10.2967/jnumed.120.244806.
Busek P, Mateu R, Zubal M, Kotackova L, Sedo A. Targeting fibroblast activation protein in cancer-prospects and caveats. Front Biosci (Landmark Ed). 2018;23:1933–68.
Lindner T, Loktev A, Giesel F, Kratochwil C, Altmann A, Haberkorn U. Targeting of activated fibroblasts for imaging and therapy. EJNMMI Radiopharmacy Chem. 2019;4:1–15. https://doi.org/10.1186/s41181-019-0069-0.
Loktev A, Lindner T, Mier W, Debus J, Altmann A, Jäger D, et al. A tumor-imaging method targeting cancer-associated fibroblasts. J Nucl Med. 2018;59:1423–9. https://doi.org/10.2967/jnumed.118.210443.
Lindner T, Loktev A, Altmann A, Giesel F, Kratochwil C, Debus J, et al. Development of quinoline-based theranostic ligands for the targeting of fibroblast activation protein. J Nucl Med. 2018;59:1415–22. https://doi.org/10.2967/jnumed.118.210443.
Kratochwil C, Flechsig P, Lindner T, Abderrahim L, Altmann A, Mier W, et al. 68Ga-FAPI PET/CT: tracer uptake in 28 different kinds of cancer. J Nucl Med. 2019;60:801–5. https://doi.org/10.2967/jnumed.119.227967.
Chen H, Pang Y, Wu J, Zhao L, Hao B, Wei J, et al. Comparison of [68Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT for the diagnosis of primary and metastatic lesions in patients with various types of cancer. Eur J Nucl Med Mol Imaging. 2020;47:1820–32. https://doi.org/10.1007/s00259-020-04769-z.
Giesel FL, Adeberg S, Syed M, Lindner T, Jiménez-Franco LD, Mavriopoulou E, et al. FAPI-74 PET/CT using either 18F-AlF or cold-kit 68Ga labeling: biodistribution, radiation dosimetry, and tumor delineation in lung cancer patients. J Nucl Med. 2021;62:201–7. https://doi.org/10.2967/jnumed.120.245084.
Loktev A, Lindner T, Burger EM, Altmann A, Giesel F, Kratochwil C, et al. Development of fibroblast activation protein-targeted radiotracers with improved tumor retention. J Nucl Med. 2019;60:1421–9. https://doi.org/10.2967/jnumed.118.224469.
Windisch P, Zwahlen DR, Koerber SA, Giesel FL, Debus J, Haberkorn U, et al. Clinical results of fibroblast activation protein (FAP) specific PET and implications for radiotherapy planning: systematic review. Cancers. 2020;12:2629. https://doi.org/10.3390/cancers12092629.
Zhang J, Hao W, Weiss OJ, Cheng Y, Niu G, Li F, et al. Safety, pharmacokinetics and dosimetry of a long-acting radiolabeled somatostatin analogue 177Lu-DOTA-EB-TATE in patients with advanced metastatic neuroendocrine tumors. J Nucl Med. 2018;59:1699–705. https://doi.org/10.2967/jnumed.118.209841.
Jie Z, Fan X, Wang H, Liu Q, Wang J, Li H, et al. First-in-human study of 177Lu-EB-PSMA-617 in patients with metastatic castration-resistant prostate cancer. Eur J Nucl Med Mol Imaging. 2019;46:148–58. https://doi.org/10.1007/s00259-018-4096-y.
Kramer V, Fernández R, Lehnert W, Jiménez-Franco LD, Soza-Ried C, Eppard E, et al. Biodistribution and dosimetry of a single dose of albumin-binding ligand [177Lu]Lu-PSMA-ALB-56 in patients with mCRPC. Eur J Nucl Med Mol Imaging. 2021;48:893–903. https://doi.org/10.1007/s00259-020-05022-3.
Kuo HT, Lin KS, Zhang Z, Uribe CF, Merkens H, Zhang C, et al. 177Lu-labeled albumin-binder-conjugated PSMA-targeting agents with extremely high tumor uptake and enhanced tumor-to-kidney absorbed dose ratio. J Nucl Med. 2021;62:521–7. https://doi.org/10.2967/jnumed.120.250738.
Liu Z, Chen X. Simple bioconjugate chemistry serves great clinical advances: albumin as a versatile platform for diagnosis and precision therapy. Chem Soc Rev. 2016;45:1432–56. https://doi.org/10.1039/c5cs00158g.
Drucker DJ, Dritselis A, Kirkpatrick P. Liraglutide. Nat Rev Drug Discovery. 2010;9:267–8. https://doi.org/10.1038/nrd3148.
Elbrønd B, Jakobsen G, Larsen S, Agerso H, Jensen LB, Rolan P, et al. Pharmacokinetics, pharmacodynamics, safety, and tolerability of a single-dose of NN2211, a long-acting glucagon-like peptide 1 derivative, in healthy male subjects. Diabetes Care. 2002;25:1398–404. https://doi.org/10.2337/diacare.25.8.1398.
Knudsen LB, Lau J. The discovery and development of liraglutide and semaglutide. Front Endocrinol. 2019;10:1–32. https://doi.org/10.3389/fendo.2019.00155.
Madsen K, Knudsen LB, Agersoe H, Nielsen PF, Thøgersen H, Wilken M, et al. Structure-activity and protraction relationship of long-acting glucagon-like peptide-1 derivatives: importance of fatty acid length, polarity, and bulkiness. J Med Chem. 2007;50:6126–32. https://doi.org/10.1021/jm070861j.
Kenyon MA, Hamilton JA. 13C NMR studies of the binding of medium-chain fatty acids to human serum albumin. J Lipid Res. 1994;35:458–67. https://doi.org/10.1016/S0022-2275(20)41196-4.
Wang Q, Wang Y, Ding J, Wang C, Zhou X, Gao W, et al. A bioorthogonal system reveals antitumour immune function of pyroptosis. Nature. 2020;579:421–6. https://doi.org/10.1038/s41586-020-2079-1.
Avila-Rodriguez MA, Nye JA, Nickles RJ. Production and separation of non-carrier-added 86Y from enriched 86Sr targets. Appl Radiat Isot. 2008;66:9–13. https://doi.org/10.1016/j.apradiso.2007.07.027.
Ren J, Xu M, Chen J, Ding J, Wang P, Huo L, et al. PET imaging facilitates antibody screening for synergistic radioimmunotherapy with a 177Lu-labeled αPD-L1 antibody. Theranostics. 2021;11:304–15. https://doi.org/10.7150/thno.45540.
Funding
This work was funded by the Natural Science Foundation of Beijing, China (Grant No. Z200018), the National Science Foundation for Post-doctoral Scientists of China (Grant No. 2020M670047), the Special Foundation of Beijing Municipal Education Commission (Grant No. 3500–12020123), the National Natural Science Foundation of China (No. NSFC U1867209 and No. NSFC 21778003), and the Ministry of Science and Technology of the People’s Republic of China (2017YFA0506300, 2020YFC2002702). Pu Zhang was supported in part by the Postdoctoral Fellowship of Peking-Tsinghua Center for Life Science.
Author information
Authors and Affiliations
Corresponding authors
Ethics declarations
Ethics approval
All animal care and experimental procedure were performed following the guidelines of the care and use of laboratory animals approved by the ethics committee of Peking University. This article does not contain any studies with human participants performed by any of the authors.
Conflict of interest
Pu Zhang, Mengxin Xu, Junyi Chen, and Zhibo Liu are the consultant of Borui Biotech. Co. Ltd.
Additional information
Publisher's note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
This article is part of the Topical Collection on Theragnostic
Supplementary Information
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Zhang, P., Xu, M., Ding, J. et al. Fatty acid-conjugated radiopharmaceuticals for fibroblast activation protein-targeted radiotherapy. Eur J Nucl Med Mol Imaging 49, 1985–1996 (2022). https://doi.org/10.1007/s00259-021-05591-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00259-021-05591-x