(99m)Tc-radiolabeled GE11-modified peptide for ovarian tumor targeting

BACKGROUND: Ovarian cancer is a serious threat for women health and the early diagnosis of this cancer might improves the survival rate of patients. The use of the targeted radiopharmaceuticals could be a non-invasive and logical method for tumor imaging. The aim of this study was to radiolabel GE11 peptide as a new specific probe for imaging of ovarian tumor. METHODS: HYNIC-SSS-GE11 peptide was labeled with (99m)Tc using tricine as a coligand. The (99m)Tc-tricine-HYNIC-SSS-GE11 peptide was evaluated for specific cellular binding in three cell lines with different levels of EGFR expression. Tumor targeting was assessed in SKOV3 tumor bearing mice. RESULTS: By using tricine as a coligand, labeling yield was more than 98% and the stability of the radiolabelled peptide in human serum up to 4 h was 96%. The in vitro cell uptake test showed that this radiolabeled peptide had a good affinity to SKOV3 cells with dissociation constant of 73 nM. The in vivo results showed a tumor/muscle ratio of 3.2 at 4 h following injection of (99m)Tc-tricine-HYNIC-SSS-GE11 peptide. CONCLUSIONS: Results of this study showed that (99m)Tc-tricine-HYNIC-SSS-GE11 peptide could be a promising tool for diagnosis and staging of ovarian cancer. GRAPHICAL ABSTRACT: (99m)Tc-tricine-HYNIC-SSS-GE11, a novl targeted agent for ovarian tumor imaging [Image: see text]