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 Tc using tricine as a coligand. The 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 Tc-tricine-HYNIC-SSS-GE11 peptide.

CONCLUSIONS

Results of this study showed that Tc-tricine-HYNIC-SSS-GE11 peptide could be a promising tool for diagnosis and staging of ovarian cancer. Tc-tricine-HYNIC-SSS-GE11, a novl targeted agent for ovarian tumor imaging.