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Corlett A, Sani MA, Van Zuylekom J, Ang CS, von Guggenberg E, Cullinane C, Blyth B, Hicks RJ, Roselt PD, Thompson PE, Hutton CA, Haskali MB. A New Turn in Peptide-Based Imaging Agents: Foldamers Afford Improved Theranostics Targeting Cholecystokinin-2 Receptor-Positive Cancer. J Med Chem 2021; 64:4841-4856. [PMID: 33826325 DOI: 10.1021/acs.jmedchem.0c02213] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Proteins adopt unique folded secondary and tertiary structures that are responsible for their remarkable biological properties. This structural complexity is key in designing efficacious peptides that can mimic the three-dimensional structure needed for biological function. In this study, we employ different chemical strategies to induce and stabilize a β-hairpin fold of peptides targeting cholecystokinin-2 receptors for theranostic application (combination of a targeted therapeutic and a diagnostic companion). The newly developed peptides exhibited enhanced folding capacity as demonstrated by circular dichroism (CD) spectroscopy, ion-mobility spectrometry-mass spectrometry, and two-dimensional (2D) NMR experiments. Enhanced folding characteristics of the peptides led to increased biological potency, affording four optimal Ga-68 labeled radiotracers ([68Ga]Ga-4b, [68Ga]Ga-11b-13b) targeting CCK-2R. In particular, [68Ga]Ga-12b and [68Ga]Ga-13b presented improved metabolic stability, enhanced cell internalization, and up to 6 fold increase in tumor uptake. These peptides hold great promise as next-generation theranostic radiopharmaceuticals.
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Affiliation(s)
- Alicia Corlett
- Department of Nuclear Medicine, The Royal Melbourne Hospital, Melbourne, VIC 3000, Australia
| | | | - Jessica Van Zuylekom
- The Centre for Molecular Imaging and Translational Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia
| | - Ching-Seng Ang
- The Mass Spectrometry and Proteomics Facility, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville 3010, Australia
| | | | - Carleen Cullinane
- The Centre for Molecular Imaging and Translational Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Benjamin Blyth
- The Centre for Molecular Imaging and Translational Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Rodney J Hicks
- The Centre for Molecular Imaging and Translational Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Peter D Roselt
- The Radiopharmaceutical Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia
| | - Philip E Thompson
- Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University (Parkville Campus), Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Parkville VIC 3052, Australia
| | | | - Mohammad B Haskali
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC 3010, Australia.,The Radiopharmaceutical Research Laboratory, The Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia
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