Identification of a Met-Binding Peptide from a Phage Display Library

• Published in: Clinical cancer research 2007-10, Vol.13 (20), p.6049-6055
• Main Authors: PING ZHAO, GRABINSKI, Tessa, HAY, Rick, CAO, Brian, CHONGFENG GAO, SKINNER, R. Scot, GIAMBERNARDI, Troy, YANLI SU, HUDSON, Eric, RESAU, James, GROSS, Milton, VANDE WOUDE, George F
• Format: Article
• Language: English
• Subjects: Animals; Antineoplastic agents; Biological and medical sciences; Cell Proliferation; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Gene Expression Regulation, Neoplastic; Hepatocyte Growth Factor - metabolism; Humans; Medical sciences; Met; Mice; Mice, Nude; Neoplasm Transplantation; NIH 3T3 Cells; nuclear imaging; Peptide Library; Peptides - chemistry; phage display; Pharmacology. Drug treatments; Proto-Oncogene Proteins c-met - metabolism; receptor tyrosine kinase
• ISSN: 1078-0432; 1557-3265
• DOI: 10.1158/1078-0432.CCR-07-0035

Purpose: Aberrant c-Met expression has been implicated in most types of human cancer. We are developing Met-directed imaging and therapeutic agents. Experimental Design: To seek peptides that bind specifically to receptor Met, the Met-expressing cell lines S114 and SK-LMS-1 were used for biopanning with a random peptide phage display library. Competition ELISA, fluorescence-activated cell sorting analysis, an internalization assay, and a cell proliferation assay were used to characterize a Met-binding peptide in vitro . To evaluate the utility of the peptide as a diagnostic agent in vivo , 125 I-labeled peptide was injected i.v. into nude mice bearing s.c. xenografts of the Met-expressing and hepatocyte growth factor (HGF)/scatter factor–expressing SK-LMS-1/HGF, and total body scintigrams were obtained between 1 and 24 h postinjection. Results: One Met-binding peptide (YLFSVHWPPLKA), designated Met-pep1, reacts with Met on the cell surface and competes with HGF/scatter factor binding to Met in a dose-dependent manner. Met-pep1 is internalized by Met-expressing cells after receptor binding. Met-pep1 inhibits human leiomyosarcoma SK-LMS-1 cell proliferation in vitro . In SK-LMS-1 mouse xenografts, tumor-associated activity was imaged as early as 1 h postinjection and remained visible in some animals as late as 24 h postinjection. Conclusions: Met-pep1 specifically interacts with Met: it is internalized by Met-expressing cells and inhibits tumor cell proliferation in vitro ; it is a potential diagnostic agent for tumor imaging.