18F labeled RGD‐A7R peptide for dual integrin and VEGF‐targeted tumor imaging in mice bearing U87MG tumors. (8th October 2014)

• Record Type: Journal Article
• Authors: Ma, Yufei; Liang, Sheng; Guo, Jun; Guo, Rui; Wang, Hui
• Is Part Of: Journal of labelled compounds & radiopharmaceuticals. Volume 57:Number 11(2014)
• Page Start: 627
• Page End: 631
• Publication Date: 2014-10-08
• Subjects: Tracers (Chemistry) -- Periodicals; Radiopharmaceuticals -- Periodicals; 615.8424
• DOI: 10.1002/jlcr.3222
• Languages: English
• ISSNs: 0362-4803

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The aim of this study is to develop a novel Arg‐Gly‐Asp acid (RGD) and Ala‐Thr‐Trp‐Leu‐Pro‐Pro‐Arg (ATWLPPR A7R) peptide‐containing ligand for <sup>18</sup>F labeling as αvβ3 and vascular endothelial growth factor receptor‐targeted imaging agent. <sup>18</sup>F‐RGD‐A7R was prepared by conjugation with <sup>18</sup>F‐SFB. The final product was purified by high‐performance liquid chromatography and tested <italic>in vitro</italic> and <italic>in vivo</italic>. Cell‐binding assays of RGD‐A7R, RGD and RGD‐A7R, A7R were tested in U87MG cells (<sup>125</sup>I‐RGDyK and <sup>125</sup>I‐A7RY as radioligand, respectively). Preliminary biodistribution of the <sup>18</sup>F‐RGD‐A7R was also evaluated. The RGD‐A7R had good integrin binding affinity (50% inhibitory concentration (IC<sub>50</sub>) = 21.67 and 23.68 nM, slightly lower than unmodified RGD (40.02 nM) and A7R (50.18 nM)). The radiotracer had receptor‐mediated activity accumulation in U87MG tumor (1.90 ± 0.34 percentage of injected dose per gram (%ID/g) at 0.5 h postinjection), which is known to be integrin positive. After blocking with RGD‐A7R, the tumor uptake was reduced to 0.47 ± 0.06 %ID/g at 0.5 h postinjection. <sup>18</sup>F‐RGD‐A7R exhibited dual receptor targeting properties both <italic>in vitro</italic> and <italic>in vivo</italic>. The favorable characterizations of <sup>18</sup>F‐RGD‐A7RY, such as convenient synthesis, high specific activity, and high tumor uptake, warrant its further investigation for clinical cancer imaging.</p> </abstract>