A stabilized CXCL9(74-103)-derived peptide selectively inhibits proliferation, adhesion and metastasis of tumor cells that express high levels of heparan sulfate

Glycosaminoglycans/proteoglycans (GAGs/PGs) regulate numerous molecular and cellular interactions during tumor progression, and are as such potentially interesting targets for anti-cancer therapy. We previously demonstrated that an L-amino acid GAG-binding peptide derived from CXCL9, CXCL9(74-103), acted angiostatically. Here, we tested whether a CXCL9(74-103) version fully consisting of D-amino acids, to provide protease resistance and stability, retained its anti-angiogenic properties. D-CXCL9(74-103) interfered with in vitro endothelial spheroid sprouting induced by VEGF165 or FGF-2 and with FGF-2-induced vessel formation in vivo. Moreover, we investigated the anti-tumoral activity of L- and D-CXCL9(74-103) on HCT116 colon carcinoma and B16-BL6 melanoma cells. The inhibitory effect of L- and D-CXCL9(74-103) on proliferation, adhesion and metastasis was considerably different on heparan sulfate high B16-BL6 versus chrondroitin sulfate high, but heparan sulfate low HCT116 cells. D-CXCL9(74-103), with high affinity for heparan sulfate, reduced B16-BL6 2D and 3D proliferation, adhesion to endothelial cells and metastatic lung dissemination. In contrast, treatment with D-CXCL9(74-103) had no effect on HCT116 cells, as the D-peptide bound chondroitin sulfate with low affinity. Altogether, our results stress the importance of tumoral GAGs in adhesion and metastasis and highlight the potential of a D-amino acid peptide, D-CXCL9(74-103), to interfere with growth and metastasis of heparan sulfate high tumors.