Preparation and cellular-interaction investigation of 177 Lu/FITC labeled NGR peptides

Aminopeptidase N (CD13) as the malignant cell surface marker is overexpressed on many tumor cells including lung cancer and the neovascular cell membranes. A tripeptide structure, Asn-Gly-Arg (NGR), can specifically bind to CD13. In this study, we successfully labeled various NGR peptides derivatives with FITC or 177Lu at high efficiency. The 177Lu labeling of the NGR peptides was stable in vitro. The cellular uptake of the 177Lu-labeled cyclic NGR peptides was different by varying the structure of peptides.