Amino acids and peptides. XXXI. Preparation of analogs of the laminin-related peptide YIGSR and their inhibitory effect on experimental metastasis.

Analogs of a partial sequence peptide of laminin, i.e., Tyr-Ile-Gly-Ser-Arg (YIGSR) analogs and Cys-Asp-Pro-Gly-Tyr-Ile-Gly-Ser-Arg (CDPGYIGSR) analogs, were prepared by the solid-phase method and their inhibitory effects on experimental metastasis of B16-BL6 melanoma cells were examined. YIGSR analogs in which Ile was replaced by other hydrophobic amino acids (Met, Leu, Phe) were inhibitory. Cys-containing analogs of YIGSR were also prepared, but were less active than the parent peptide, YIGSR. Among them, CYIGSR was easily oxidized to form a disulfide bond. A Cys-containing YIGSR analog cyclized through a disulfide bond, cyclo(CYIGSRC)G, was prepared. The disulfide bond formation was performed on the resin by the silyl chloride-sulfoxide method and by the iodine oxidation method. The yield of the silyl chloride-sulfoxide method was much better than that of the iodine oxidation method.