Preclinical Evaluation of the GRPR-Targeting Antagonist RM26 Conjugated to the Albumin-Binding Domain for GRPR-Targeting Therapy of Cancer
Overview
Authors
Affiliations
The targeting of gastrin-releasing peptide receptors (GRPR) was recently proposed for targeted therapy, e.g., radiotherapy. Multiple and frequent injections of peptide-based therapeutic agents would be required due to rapid blood clearance. By conjugation of the GRPR antagonist RM26 (D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH) to an ABD (albumin-binding domain), we aimed to extend the blood circulation of peptides. The synthesized conjugate DOTA-ABD-RM26 was labelled with indium-111 and evaluated in vitro and in vivo. The labelled conjugate was stable in PBS and retained specificity and its antagonistic function against GRPR. The half-maximal inhibitory concentration (IC) of In-DOTA-ABD-RM26 in the presence of human serum albumin was 49 ± 5 nM. [In]In-DOTA-ABD-RM26 had a significantly longer residence time in blood and in tumors (without a significant decrease of up to 144 h pi) than the parental RM26 peptide. We conclude that the ABD-RM26 conjugate can be used for GRPR-targeted therapy and delivery of cytotoxic drugs. However, the undesirable elevated activity uptake in kidneys abolishes its use for radionuclide therapy. This proof-of-principle study justified further optimization of the molecular design of the ABD-RM26 conjugate.
GRPR Drives Metastasis via CRABP2 and FNDC4 Pathways in Lung Adenocarcinoma.
Kim D, Choi E, Ahn H, Kim Y Cells. 2025; 13(24.
PMID: 39768218 PMC: 11674891. DOI: 10.3390/cells13242128.
Evaluation of ABD-Linked RM26 Conjugates for GRPR-Targeted Drug Delivery.
Nagy A, Abouzayed A, Kanellopoulos P, Landmark F, Bezverkhniaia E, Tolmachev V ACS Omega. 2024; 9(34):36122-36133.
PMID: 39220525 PMC: 11359615. DOI: 10.1021/acsomega.4c00489.
Kanellopoulos P, Mattsson A, Abouzayed A, Obeid K, Nock B, Tolmachev V EJNMMI Radiopharm Chem. 2024; 9(1):13.
PMID: 38366299 PMC: 10873254. DOI: 10.1186/s41181-024-00242-6.
Cheng L, Yang T, Zhang J, Gao F, Yang L, Tao W Korean J Radiol. 2023; 24(6):574-589.
PMID: 37271211 PMC: 10248352. DOI: 10.3348/kjr.2022.1002.
Gomena J, Vari B, Olah-Szabo R, Biri-Kovacs B, Bosze S, Borbely A Int J Mol Sci. 2023; 24(4).
PMID: 36834815 PMC: 9967152. DOI: 10.3390/ijms24043400.