IN-VIVO BINDING OF THE RADIOIODINATED PEPTIDE YIGSR ON B16 MELANOMA-CELLS

It has been reported that metastatic melanoma cell lines selectively b ind in vitro with the synthetic laminin pentapeptide tyrosyl-isoleucyl -glycyl-seryl-arginine (YIGSR), The aim of this study was to investiga te whether the same peptide can bind on melanoma cells in vivo as well . Iodine-125-labeled YIGSR was administered to B16 melanoma-bearing an imals, Microscopic autoradiography of tumor and organ sections taken 2 4 h after peptide administration showed that the peptide did accumulat e on the surface of certain tumor cells. The peptide binding cells wer e frequent in metastatic sites and tumors grown for 24 days and rare i n tumors grown for 10 days. A similarly radiolabeled control pentapept ide (peptide DRLKY) did not bind to any tumor cell, It is suggested th at the YIGSR binding tumor cells may represent a distinct melanoma cel l population with a high metastatic potential.