Ullrich Martin, Brandt Florian, Löser Reik, Pietzsch Jens, Wodtke Robert
Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, Dresden 01328, Germany.
School of Science, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstraße 4, Dresden 01069, Germany.
ACS Omega. 2023 Jun 22;8(26):24003-24009. doi: 10.1021/acsomega.3c02755. eCollection 2023 Jul 4.
The development of novel ligands for G-protein-coupled receptors (GPCRs) typically entails the characterization of their binding affinity, which is often performed with radioligands in a competition or saturation binding assay format. Since GPCRs are transmembrane proteins, receptor samples for binding assays are prepared from tissue sections, cell membranes, cell homogenates, or intact cells. As part of our investigations on modulating the pharmacokinetics of radiolabeled peptides for improved theranostic targeting of neuroendocrine tumors with a high abundance of the somatostatin receptor sub-type 2 (SST), we characterized a series of Cu-labeled [Tyr]octreotate (TATE) derivatives in vitro in saturation binding assays. Herein, we report on the SST binding parameters measured toward intact mouse pheochromocytoma cells and corresponding cell homogenates and discuss the observed differences taking the physiology of SST and GPCRs in general into account. Furthermore, we point out method-specific advantages and limitations.
开发用于G蛋白偶联受体（GPCR）的新型配体通常需要对其结合亲和力进行表征，这通常在竞争或饱和结合试验中用放射性配体来完成。由于GPCR是跨膜蛋白，用于结合试验的受体样品是从组织切片、细胞膜、细胞匀浆或完整细胞中制备的。作为我们关于调节放射性标记肽的药代动力学以改善对具有高丰度生长抑素受体2型（SST）的神经内分泌肿瘤进行治疗诊断靶向研究的一部分，我们在体外饱和结合试验中对一系列铜标记的[酪氨酸]奥曲肽（TATE）衍生物进行了表征。在此，我们报告了针对完整小鼠嗜铬细胞瘤细胞和相应细胞匀浆测得的SST结合参数，并结合SST和GPCR的一般生理学情况讨论了观察到的差异。此外，我们指出了方法的特定优点和局限性。
