Evaluation of Angiotensin-Converting Enzyme 2 Expression In Vivo with Novel 68Ga-Labeled Peptides Originated from the Coronavirus Receptor-Binding Domain

Linlin Li; Rongxi Wang; Li He; Hua Guo; Lei Fu; Guochang Wang; Jiarou Wang; Ziying Chen; Xingtong Peng; Xinyu Lu; Huimin Sui; Yuanyuan Jiang; Jie Zang; Lianghui Gao; Zhaohui Zhu

doi:10.1021/acsptsci.4c00316

Evaluation of Angiotensin-Converting Enzyme 2 Expression In Vivo with Novel ⁶⁸Ga-Labeled Peptides Originated from the Coronavirus Receptor-Binding Domain

ACS Pharmacol Transl Sci. 2024 Sep 12;7(10):3119-3130. doi: 10.1021/acsptsci.4c00316. eCollection 2024 Oct 11.

Authors

Linlin Li¹, Rongxi Wang¹, Li He², Hua Guo³, Lei Fu², Guochang Wang⁴, Jiarou Wang¹, Ziying Chen², Xingtong Peng⁵, Xinyu Lu⁵, Huimin Sui¹, Yuanyuan Jiang¹, Jie Zang⁴, Lianghui Gao², Zhaohui Zhu¹

Affiliations

¹ Department of Nuclear Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Beijing Key Laboratory of Molecular Targeted Diagnosis and Therapy in Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100730, China.
² Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
³ State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
⁴ Department of Nuclear Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, China.
⁵ Eight-Year Program of Clinical Medicine, Peking Union Medical College Hospital (PUMCH), Chinese Academy of Medical Sciences (CAMS) and Peking Union Medical College (PUMC), Beijing 100730, China.

PMID: 39416971
PMCID: PMC11475584 (available on 2025-09-12)
DOI: 10.1021/acsptsci.4c00316

Abstract

Angiotensin-converting enzyme 2 (ACE2) is not only a key to the renin-angiotensin-aldosterone system and related diseases, but also the main entry point on cell surfaces for certain coronaviruses, including severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2. By analyzing the different key binding sites from the receptor-binding domain (RBD) of SARS-CoV and SARS-CoV-2, nine new ACE2-targeting peptides (A1 to A9) were designed, synthesized and connected with a chelator, 1,4,7-triazacyclononane-N,N',N''-triacetic acid (NOTA). NOTA-A1, NOTA-A2, NOTA-A4, NOTA-A5, and NOTA-A8 were successfully labeled with [⁶⁸Ga]Ga³⁺ and were used for biological evaluation. [⁶⁸Ga]Ga-NOTA-A2, [⁶⁸Ga]Ga-NOTA-A5, and [⁶⁸Ga]Ga-NOTA-A8 showed specific binding to ACE2 via cell assays, and their binding sites and binding capacity were calculated by molecular docking and molecular dynamics simulations. In tumor-bearing mice, A549 tumors were visualized 60 min postinjection of [⁶⁸Ga]Ga-NOTA-A2, [⁶⁸Ga]Ga-NOTA-A5, or [⁶⁸Ga]Ga-NOTA-A8. These peptides also accumulated in the organs with high-level ACE2 expression, confirmed by immunohistochemical stain. Among them, [⁶⁸Ga]Ga-NOTA-A5 exhibited the highest tumor uptake and tumor/background ratio, and it successfully tracked the increased ACE2 levels in mice tissues after excessive Losartan treatment. In a first-in-human study, the distribution of [⁶⁸Ga]Ga-NOTA-A5 was evaluated with positron emission tomography/computed tomography (PET/CT) in three participants without adverse events. ⁶⁸Ga-labeled peptides originated from the coronavirus RBD, with [⁶⁸Ga]Ga-NOTA-A5 as a typical representative, seem to be safe and effective for the evaluation of ACE2 expression in vivo with PET/CT, facilitating further mechanism investigation and clinical evaluation of ACE2-related diseases.