1
|
Šlachtová V, Motornov V, Beier P, Vrabel M. Bioorthogonal Cycloadditions of C3-Trifluoromethylated 1,2,4-Triazines with trans-Cyclooctenes. Chemistry 2024; 30:e202400839. [PMID: 38739300 DOI: 10.1002/chem.202400839] [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: 02/29/2024] [Revised: 05/13/2024] [Accepted: 05/13/2024] [Indexed: 05/14/2024]
Abstract
1,2,4-triazines are a valuable class of heterodienes that can be employed in inverse electron-demand Diels-Alder reactions. However, their broader application in bioorthogonal chemistry is limited due to their low reactivity. This article focuses on 3-(trifluoromethyl)-1,2,4-triazines, which can be efficiently prepared in a one-pot reaction from NH-1,2,3-triazoles. These triazines are highly reactive in reactions with strained cyclooctenes, giving second-order rate constants as high as 230 M-1 s-1. Despite their high reactivity, the compounds remain sufficiently stable under biologically relevant conditions. We show that some of the compounds are fluorogenic, a property of potential use in bioimaging. In addition, we demonstrate the successful application of the triazines in labeling model biomolecules. Our work shows that the reactivity of 1,2,4-triazines can be enhanced by the 3-CF3-substitution, which we consider an important step toward the wider use of this promising class of reagents.
Collapse
Affiliation(s)
- Veronika Šlachtová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10, Prague, Czech Republic
| | - Vladimir Motornov
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10, Prague, Czech Republic
| | - Petr Beier
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10, Prague, Czech Republic
| | - Milan Vrabel
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 166 10, Prague, Czech Republic
| |
Collapse
|
2
|
Mitry MMA, Dallas ML, Boateng SY, Greco F, Osborn HMI. Selective activation of prodrugs in breast cancer using metabolic glycoengineering and the tetrazine ligation bioorthogonal reaction. Bioorg Chem 2024; 147:107304. [PMID: 38643563 DOI: 10.1016/j.bioorg.2024.107304] [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: 01/25/2024] [Revised: 03/14/2024] [Accepted: 03/19/2024] [Indexed: 04/23/2024]
Abstract
Increasing the selectivity of chemotherapies by converting them into prodrugs that can be activated at the tumour site decreases their side effects and allows discrimination between cancerous and non-cancerous cells. Herein, the use of metabolic glycoengineering (MGE) to selectively label MCF-7 breast cancer cells with tetrazine (Tz) activators for subsequent activation of prodrugs containing the trans-cyclooctene (TCO) moiety by a bioorthogonal reaction is demonstrated. Three novel Tz-modified monosaccharides, Ac4ManNTz 7, Ac4GalNTz 8, and Ac4SiaTz 16, were used for expression of the Tz activator within sialic-acid rich breast cancer cells' surface glycans through MGE. Tz expression on breast cancer cells (MCF-7) was evaluated versus the non-cancerous L929 fibroblasts showing a concentration-dependant effect and excellent selectivity with ≥35-fold Tz expression on the MCF-7 cells versus the non-cancerous L929 fibroblasts. Next, a novel TCO-N-mustard prodrug and a TCO-doxorubicin prodrug were analyzed in vitro on the Tz-bioengineered cells to probe our hypothesis that these could be activated via a bioorthogonal reaction. Selective prodrug activation and restoration of cytotoxicity were demonstrated for the MCF-7 breast cancer cells versus the non-cancerous L929 cells. Restoration of the parent drug's cytotoxicity was shown to be dependent on the level of Tz expression where the Ac4ManNTz 7 and Ac4GalNTz 8 derivatives (20 µM) lead to the highest Tz expression and full restoration of the parent drug's cytotoxicity. This work suggests the feasibility of combining MGE and tetrazine ligation for selective prodrug activation in breast cancer.
Collapse
Affiliation(s)
- Madonna M A Mitry
- Reading School of Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD. UK; Dept. of Pharmaceutical Chemistry, Faculty of Pharmacy, Ain Shams University, Cairo 11566, Egypt.
| | - Mark L Dallas
- Reading School of Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD. UK.
| | - Samuel Y Boateng
- School of Biological Sciences, University of Reading, Whiteknights, Reading RG6 6UB, UK.
| | - Francesca Greco
- Reading School of Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD. UK.
| | - Helen M I Osborn
- Reading School of Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD. UK.
| |
Collapse
|
3
|
Doelman W, Ligthart NAM, van de Plassche MAT, de Geus MAR, Reinalda L, Isendoorn MME, Filippov DV, van Kasteren SI. Synthesis of Peptides Containing a Combination of Free and 2-trans-Cyclooctene Carbamate Protected Lysine Residues. Chembiochem 2024; 25:e202300786. [PMID: 38126970 DOI: 10.1002/cbic.202300786] [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: 11/22/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 12/23/2023]
Abstract
The allylic trans-cyclooctene (TCO) functionality facilitates powerful control over the spatiotemporal activity of bio-active molecules, enabling precision targeting of druglike and imaging modalities. However, the introduction of this function onto molecules remains chemically challenging, particularly for peptides. Modification with TCOs of this important class of biomolecules remains a challenge, primarily due to the sensitivity of the TCO group to the strong acids typically used in global deprotection during solid phase peptide synthesis. Here, we present a novel synthetic approach to site-selectively introduce TCO-groups in peptides. Our approach utilizes azide groups to mask amine functions, enabling selective introduction of the TCO on a single lysine residue. Staudinger reduction of the azides back to the corresponding amines proceeds without disturbing the sensitive TCO. We show that using our method, we can produce TCO-inactivated antigenic peptides of previously unseen complexity.
Collapse
Affiliation(s)
- W Doelman
- Leiden Institute of Chemistry, Leiden, the Netherlands
| | | | | | - M A R de Geus
- Leiden Institute of Chemistry, Leiden, the Netherlands
| | - L Reinalda
- Leiden Institute of Chemistry, Leiden, the Netherlands
| | | | - D V Filippov
- Leiden Institute of Chemistry, Leiden, the Netherlands
| | | |
Collapse
|
4
|
Hebels ER, Dietl S, Timmers M, Hak J, van den Dikkenberg A, Rijcken CJ, Hennink WE, Liskamp RMJ, Vermonden T. Versatile Click Linker Enabling Native Peptide Release from Nanocarriers upon Redox Trigger. Bioconjug Chem 2023; 34:2375-2386. [PMID: 38079189 PMCID: PMC10739580 DOI: 10.1021/acs.bioconjchem.3c00484] [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: 11/05/2023] [Revised: 11/19/2023] [Accepted: 11/20/2023] [Indexed: 12/21/2023]
Abstract
Nanocarriers have shown their ability to extend the circulation time of drugs, enhance tumor uptake, and tune drug release. Therapeutic peptides are a class of drug compounds in which nanocarrier-mediated delivery can potentially improve their therapeutic index. To this end, there is an urgent need for orthogonal covalent linker chemistry facilitating the straightforward on-the-resin peptide generation, nanocarrier conjugation, as well as the triggered release of the peptide in its native state. Here, we present a copper-free clickable ring-strained alkyne linker conjugated to the N-terminus of oncolytic peptide LTX-315 via standard solid-phase peptide synthesis (SPPS). The linker contains (1) a recently developed seven-membered ring-strained alkyne, 3,3,6,6-tetramethylthiacycloheptyne sulfoximine (TMTHSI), (2) a disulfide bond, which is sensitive to the reducing cytosolic and tumor environment, and (3) a thiobenzyl carbamate spacer enabling release of the native peptide upon cleavage of the disulfide via 1,6-elimination. We demonstrate convenient "clicking" of the hydrophilic linker-peptide conjugate to preformed pegylated core-cross-linked polymeric micelles (CCPMs) of 50 nm containing azides in the hydrophobic core under aqueous conditions at room temperature resulting in a loading capacity of 8 mass % of peptide to polymer (56% loading efficiency). This entrapment of hydrophilic cargo into/to a cross-linked hydrophobic core is a new and counterintuitive approach for this class of nanocarriers. The release of LTX-315 from the CCPMs was investigated in vitro and rapid release upon exposure to glutathione (within minutes) followed by slower 1,6-elimination (within an hour) resulted in the formation of the native peptide. Finally, cytotoxicity of LTX CCPMs as well as uptake of sulfocyanine 5-loaded CCPMs was investigated by cell culture, demonstrating successful tumor cell killing at concentrations similar to that of the free peptide treatment.
Collapse
Affiliation(s)
- Erik R. Hebels
- Division
of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht 3508 TB, The Netherlands
| | - Stefanie Dietl
- Division
of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht 3508 TB, The Netherlands
| | - Matt Timmers
- Division
of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht 3508 TB, The Netherlands
- Cristal
Therapeutics, Maastricht 6229 EV, The Netherlands
| | - Jaimie Hak
- Division
of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht 3508 TB, The Netherlands
| | - Antionette van den Dikkenberg
- Division
of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht 3508 TB, The Netherlands
| | | | - Wim E. Hennink
- Division
of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht 3508 TB, The Netherlands
| | - Rob M. J. Liskamp
- Cristal
Therapeutics, Maastricht 6229 EV, The Netherlands
- Department
of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht 6229 ER, The Netherlands
- School
of Chemistry, University of Glasgow, Glasgow G12 8QQ, U.K.
| | - Tina Vermonden
- Division
of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht 3508 TB, The Netherlands
| |
Collapse
|
5
|
Šlachtová V, Bellová S, La-Venia A, Galeta J, Dračínský M, Chalupský K, Dvořáková A, Mertlíková-Kaiserová H, Rukovanský P, Dzijak R, Vrabel M. Triazinium Ligation: Bioorthogonal Reaction of N1-Alkyl 1,2,4-Triazinium Salts. Angew Chem Int Ed Engl 2023; 62:e202306828. [PMID: 37436086 DOI: 10.1002/anie.202306828] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 07/12/2023] [Accepted: 07/12/2023] [Indexed: 07/13/2023]
Abstract
The development of reagents that can selectively react in complex biological media is an important challenge. Here we show that N1-alkylation of 1,2,4-triazines yields the corresponding triazinium salts, which are three orders of magnitude more reactive in reactions with strained alkynes than the parent 1,2,4-triazines. This powerful bioorthogonal ligation enables efficient modification of peptides and proteins. The positively charged N1-alkyl triazinium salts exhibit favorable cell permeability, which makes them superior for intracellular fluorescent labeling applications when compared to analogous 1,2,4,5-tetrazines. Due to their high reactivity, stability, synthetic accessibility and improved water solubility, the new ionic heterodienes represent a valuable addition to the repertoire of existing modern bioorthogonal reagents.
Collapse
Affiliation(s)
- Veronika Šlachtová
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 16000, Prague, Czech Republic
| | - Simona Bellová
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 16000, Prague, Czech Republic
| | - Agustina La-Venia
- Current address: Instituto de Química Rosario, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario-CONICET, Suipacha 531, S2002LRK, Rosario, Argentina
| | - Juraj Galeta
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 16000, Prague, Czech Republic
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 16000, Prague, Czech Republic
| | - Karel Chalupský
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 16000, Prague, Czech Republic
| | - Alexandra Dvořáková
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 16000, Prague, Czech Republic
| | - Helena Mertlíková-Kaiserová
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 16000, Prague, Czech Republic
| | - Peter Rukovanský
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 16000, Prague, Czech Republic
| | - Rastislav Dzijak
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 16000, Prague, Czech Republic
| | - Milan Vrabel
- Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo nám. 2, 16000, Prague, Czech Republic
| |
Collapse
|
6
|
Timmers M, Kipper A, Frey R, Notermans S, Voievudskyi M, Wilson C, Hentzen N, Ringle M, Bovino C, Stump B, Rijcken CJF, Vermonden T, Dijkgraaf I, Liskamp R. Exploring the Chemical Properties and Medicinal Applications of Tetramethylthiocycloheptyne Sulfoximine Used in Strain-Promoted Azide-Alkyne Cycloaddition Reactions. Pharmaceuticals (Basel) 2023; 16:1155. [PMID: 37631074 PMCID: PMC10459143 DOI: 10.3390/ph16081155] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/27/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
The recently developed compound, tetramethylthiocycloheptyne sulfoximine (TMTHSI), has shown to be a promising strained alkyne for strain-promoted azide-alkyne cycloaddition (SPAAC), metal-free click chemistry. This research explores the properties of TMTHSI-based compounds via three aspects: (1) large-scale production, (2) unique stability in acidic conditions and its subsequent use in peptide synthesis, and (3) the functionalization of antibodies. Here, it is shown that (1) scale-up is achieved on a scale of up to 100 g. (2) TMTHSI is remarkably stable against TFA allowing for the site-specific functionalization of peptides on resin. Finally, (3) the functionalization of an antibody with a model payload is very efficient, with antibody conjugation demonstrating more beneficial features such as a high yield and limited hydrophobicity as compared to other alkyne reagent conjugates. These results illustrate the high potential of TMTHSI for diverse bioconjugation applications, with production already being GMP-compatible and a highly efficient conversion resulting in attractive costs of goods.
Collapse
Affiliation(s)
- Matt Timmers
- Cristal Therapeutics, 6229 EV Maastricht, The Netherlands
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutic Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands
| | | | - Raphael Frey
- Lonza AG, Bioconjugates Development, Rottenstr., 3930 Visp, Switzerland (N.H.); (M.R.); (B.S.)
| | - Stef Notermans
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229 ER Maastricht, The Netherlands
| | | | - Claire Wilson
- School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
| | - Nina Hentzen
- Lonza AG, Bioconjugates Development, Rottenstr., 3930 Visp, Switzerland (N.H.); (M.R.); (B.S.)
| | - Michael Ringle
- Lonza AG, Bioconjugates Development, Rottenstr., 3930 Visp, Switzerland (N.H.); (M.R.); (B.S.)
| | - Clara Bovino
- Lonza AG, Bioconjugates Development, Rottenstr., 3930 Visp, Switzerland (N.H.); (M.R.); (B.S.)
| | - Bernhard Stump
- Lonza AG, Bioconjugates Development, Rottenstr., 3930 Visp, Switzerland (N.H.); (M.R.); (B.S.)
| | | | - Tina Vermonden
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutic Sciences, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Ingrid Dijkgraaf
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Rob Liskamp
- Cristal Therapeutics, 6229 EV Maastricht, The Netherlands
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229 ER Maastricht, The Netherlands
- School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
| |
Collapse
|
7
|
Maisonial-Besset A, Witkowski T, Quintana M, Besse S, Gaumet V, Cordonnier A, Alliot C, Vidal A, Denevault-Sabourin C, Tarrit S, Levesque S, Miot-Noirault E, Chezal JM. Synthesis and In Vitro Comparison of DOTA, NODAGA and 15-5 Macrocycles as Chelators for the 64Cu-Labelling of Immunoconjugates. Molecules 2022; 28:molecules28010075. [PMID: 36615280 PMCID: PMC9822305 DOI: 10.3390/molecules28010075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/12/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022] Open
Abstract
The development of 64Cu-based immuno-PET radiotracers requires the use of copper-specific bifunctional chelators (BFCs) that contain functional groups allowing both convenient bioconjugation and stable copper complexes to limit in vivo bioreduction, transmetallation and/or transchelation. The excellent in vivo kinetic inertness of the pentaazamacrocyclic [64Cu]Cu-15-5 complex prompted us to investigate its potential for the 64Cu-labelling of monoclonal antibodies (mAbs), compared with the well-known NODAGA and DOTA chelators. To this end, three NODAGA, DOTA and 15-5-derived BFCs, containing a pendant azadibenzocyclooctyne moiety, were synthesised and a robust methodology was determined to form covalent bonds between them and azide-functionalised trastuzumab, an anti-HER2 mAb, using strain-promoted azide-alkyne cycloaddition. Unlike the DOTA derivative, the NODAGA- and 15-5-mAb conjugates were radiolabelled with 64Cu, obtaining excellent radiochemical yields, under mild conditions. Although all the radioimmunoconjugates showed excellent stability in PBS or mouse serum, [64Cu]Cu-15-5- and [64Cu]Cu-NODAGA-trastuzumab presented higher resistance to transchelation when challenged by EDTA. Finally, the immunoreactive fraction of the radioimmunoconjugates (88-94%) was determined in HER-2 positive BT474 human breast cancer cells, confirming that the bioconjugation and radiolabelling processes implemented had no significant impact on antigen recognition.
Collapse
Affiliation(s)
- Aurélie Maisonial-Besset
- Université Clermont Auvergne, Inserm, Imagerie Moléculaire et Stratégies Théranostiques, UMR 1240, F-63000 Clermont-Ferrand, France
| | - Tiffany Witkowski
- Université Clermont Auvergne, Inserm, Imagerie Moléculaire et Stratégies Théranostiques, UMR 1240, F-63000 Clermont-Ferrand, France
| | - Mercedes Quintana
- Université Clermont Auvergne, Inserm, Imagerie Moléculaire et Stratégies Théranostiques, UMR 1240, F-63000 Clermont-Ferrand, France
| | - Sophie Besse
- Université Clermont Auvergne, Inserm, Imagerie Moléculaire et Stratégies Théranostiques, UMR 1240, F-63000 Clermont-Ferrand, France
| | - Vincent Gaumet
- Université Clermont Auvergne, Inserm, Imagerie Moléculaire et Stratégies Théranostiques, UMR 1240, F-63000 Clermont-Ferrand, France
| | - Axel Cordonnier
- Université Clermont Auvergne, Inserm, Imagerie Moléculaire et Stratégies Théranostiques, UMR 1240, F-63000 Clermont-Ferrand, France
| | | | | | - Caroline Denevault-Sabourin
- GICC EA7501, Team IMT, Université de Tours, UFR de Médecine, Bâtiment Vialle, 10 Boulevard Tonnellé, BP 3223, CEDEX 01, 37032 Tours, France
| | - Sébastien Tarrit
- Université Clermont Auvergne, Inserm, Imagerie Moléculaire et Stratégies Théranostiques, UMR 1240, F-63000 Clermont-Ferrand, France
| | - Sophie Levesque
- Department of Nuclear Medicine, Jean Perrin Comprehensive Cancer Centre, F-63011 Clermont-Ferrand, France
| | - Elisabeth Miot-Noirault
- Université Clermont Auvergne, Inserm, Imagerie Moléculaire et Stratégies Théranostiques, UMR 1240, F-63000 Clermont-Ferrand, France
| | - Jean-Michel Chezal
- Université Clermont Auvergne, Inserm, Imagerie Moléculaire et Stratégies Théranostiques, UMR 1240, F-63000 Clermont-Ferrand, France
- Correspondence:
| |
Collapse
|
8
|
Handula M, Verhoeven M, Chen KT, Haeck J, de Jong M, Dalm SU, Seimbille Y. Towards Complete Tumor Resection: Novel Dual-Modality Probes for Improved Image-Guided Surgery of GRPR-Expressing Prostate Cancer. Pharmaceutics 2022; 14:pharmaceutics14010195. [PMID: 35057090 PMCID: PMC8778164 DOI: 10.3390/pharmaceutics14010195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 02/01/2023] Open
Abstract
Nuclear and optical dual-modality probes can be of great assistance in prostate cancer localization, providing the means for both preoperative nuclear imaging and intraoperative surgical guidance. We developed a series of probes based on the backbone of the established GRPR-targeting radiotracer NeoB. The inverse electron demand of the Diels–Alder reaction was used to integrate the sulfo-cyanine 5 dye. Indium-111 radiolabeling, stability studies and a competition binding assay were carried out. Pilot biodistribution and imaging studies were performed in PC-3 tumor-bearing mice, using the best two dual-labeled probes. The dual-modality probes were radiolabeled with a high yield (>92%), were proven to be hydrophilic and demonstrated high stability in mouse serum (>94% intact labeled ligand at 4 h). The binding affinity for the GRPR was in the nanomolar range (21.9–118.7 nM). SPECT/CT images at 2 h p.i. clearly visualized the tumor xenograft and biodistribution studies, after scanning confirmed the high tumor uptake (8.47 ± 0.46%ID/g and 6.90 ± 0.81%ID/g for probe [111In]In-12 and [111In]In-15, respectively). Receptor specificity was illustrated with blocking studies, and co-localization of the radioactive and fluorescent signal was verified by ex vivo fluorescent imaging. Although optimal tumor-to-blood and tumor-to-kidney ratios might not yet have been reached due to the prolonged blood circulation, our probes are promising candidates for the preoperative and intraoperative visualization of GRPR-positive prostate cancer.
Collapse
Affiliation(s)
- Maryana Handula
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands; (M.H.); (M.V.); (S.U.D.)
| | - Marjolein Verhoeven
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands; (M.H.); (M.V.); (S.U.D.)
| | - Kuo-Ting Chen
- Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974301, Taiwan;
| | - Joost Haeck
- AMIE Core Facility, Erasmus MC, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands;
| | - Marion de Jong
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands; (M.H.); (M.V.); (S.U.D.)
| | - Simone U. Dalm
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands; (M.H.); (M.V.); (S.U.D.)
| | - Yann Seimbille
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 GD Rotterdam, The Netherlands; (M.H.); (M.V.); (S.U.D.)
- Life Sciences Division, TRIUMF, Vancouver, BC V6T 2A3, Canada
- Correspondence: ; Tel.: +31-10-703-8961
| |
Collapse
|