Inhibition of experimental metastasis of murine fibrosarcoma cells by oligopeptide analogues to the fibronectin cell binding site

We have analyzed the effect of the synthetic oligopeptides Gly‐Arg‐Gly‐Asp‐Ser‐Pro (GRGDSP) and Gly‐Arg‐Gly‐Glu‐Ser‐Pro (GRGESP), analogues to the fibronectin cell‐binding sequence, on the formation of experimental lung metastasis. SR‐BALB were injected alone or in conjunction with GRGDSP or GRGESP in the tail vein of BALB/c mice. Co‐injection with GRGESP reduced by approximately 70% the number of metastatic colonies per mouse. However, co‐injection with the closely related peptide GRGDSP, containing the conservative substitution Glu/Asp, did not affect metastatic behavior. GRGESP peptide anti‐metastatic activity was not due to a toxic effect on tumor cells or on mice. In vitro adhesion assays testing for a possible effect of the peptide on cell‐matrix interactions indicated that the GRGESP peptide did not affect cell adhesion to the matrix proteins tested. Copyright © 1989 Wiley‐Liss, Inc., A Wiley Company.