Sialyl Lewis X-dependent lung colonization of B16 melanoma cells through a selectin-like endothelial receptor distinct from E- or P-selectin.

Endothelial carbohydrate binding proteins, E- and P-selectins, are thought to mediate sialyl Lewis A/X-dependent hematogenous cancer metastasis. We tested this hypothesis using sialyl Lewis X-dependent B16 melanoma lung targeting and its inhibition with selectin ligand mimicry peptide, IELLQAR. In E/P-selectin doubly deficient mutant mice, sialyl Lewis X-expressing B16 melanoma cells colonized the lung, and IELLQAR inhibited this colonization. However, tumors grown in E/P-selectin-deficient mice were significantly smaller than those grown in wild-type mice. These results indicate that the IELLQAR peptide receptor expressed in the lung vasculature plays a major role in sialyl Lewis X-dependent cancer cells targeting to the lung.