Loss of Wnt-5a protein expression in breast carcinoma patients is associated with a shorter recurrence-free survival as well as increased motility in mammary cell lines. Based on sequence analysis of Wnt-5a 13 peptide fragments were identified and investigated for their ability to mimic the effects of the Wnt-5 a protein on mammary cell adhesion and motility. Two of these peptides significantly increased adhesion and impaired the motility of non-tumourigenic brest cancer cell lines, both low in engogenous Wnt-5a expression. To identify the shortest possible peptide that still had an anti-motile effect, sequential deletions of two amino acids from the N-terminal side of the shorter of these two peptides were performed. The effect on tumour cell adhesion was gradually lost, and when only 6 amino acids remained the effect was not detectabel. However, formylation of the N-terminal methionine of this hexapeptide restored its effect on adhesion and reduced tumour cell motility. The novel formyl-Met-Asp-Gly-Cys-Glu-Leu peptide ligand can serve as a lead substance for anti-metastatic treatment in the <<50 % of human breast cancers where the endogenous expression of Wnt-5a is reduced.
