Synthesis of a novel 99m Tc labeled GE11 peptide for EGFR SPECT imaging

• Published in: International journal of radiation biology Vol. 96; no. 11; pp. 1443 - 1451
• Main Authors: Jiao, Honglei, Zhao, Xinming, Han, Jingya, Zhang, Jingmian, Wang, Jianfang
• Format: Journal Article
• Language: English
• Published: England 01.11.2020
• Subjects: 99mTc-labeled peptide conjugates; NSCLC; radionuclide imaging; EGFR; SPECT
• ISSN: 0955-3002; 1362-3095
• DOI: 10.1080/09553002.2020.1811419

This study investigated a novel SPECT agent for the noninvasive imaging of EGFR-overexpressing tumors. The EGFR-targeting peptide GE11 was synthesized with the introduction of four amino acids (GGGC) to its C-terminal to act as a strong chelator and radiolabeled using Tc. The radiochemical yield of the Tc-peptide-GE11 were evaluated using RP-HPLC. Cellular assays of the probe were performed on two NSCLC cell lines: A549 (high expression) and H23 (low expression). Biodistribution and SPECT imaging were performed in BALB/c nude mice bearing A549 and H23 NSCLC xenografts. The Tc-peptide-GE11 was prepared at high efficiency with radiochemical yield of 98.40 ± 1.00 % and it showed favorable stability. The cellular uptake was significantly higher in A549 than in H23 at all time points (especially at 1 h, which was 10.34 ± 0.72 and 2.04 ± 0.18, respectively). A nearly 56% reduction in probe uptake was observed after pretreatment with excess unlabeled peptides. The performance of SPECT imaging and biodistribution demonstrated higher uptake of the Tc-peptide-GE11 in A549 xenograft than in H23 xenografts. The new SPECT tracer c-peptide-GE11 showed EGFR specificity, favorable pharmacokinetics and great potential for EGFR-targeted imaging.