Fig. 1.

Identification of small peptide affinity ligands for targeted molecular probes using phage display. A: a cyclic RPMC peptide motif was identified in this study as a potential high-affinity ligand for colorectal cancer. B: fluorescently labeled cyclic RPMC was avidly internalized by HT-29 colorectal cancer cells to a far greater extent than with a labeled control peptide as shown in C. D: uptake was greater with incubation at 37°C than E, at 4°C. Samples of colon cancer (F) and normal colon mucosa (G) from tissue microarrays incubated with labeled cyclic RPMC and TOPRO-3, a nuclear counterstain, show preferential binding of the labeled peptide to malignant tissue. Reproduced with permission from Ref. 65.