Abstract 5179: Inhibition of U937-cell adhesion to human endothelial cells by glycosylated lysozyme mutants

The evascularization of cells is an important step in defense reactions and the spreading of metastases. During inflammation, the endothelium of the affected tissue becomes activated and interacts with cells bearing cognate structures such as sialyl Lewis X (sLex) substances. In this study, we present the sLex-antagonist hLysII/IV-FUCTVI by which a significant inhibition of adhesion is achieved at 1ng/ml (0.07 nM), making it the most potent known inhibitors of adhesion described to date. In our study we overexpressed the glycosylated human lysozyme mutant hLysII/IV in CHO cells stably expressing fucosyltransferases FUCIII, IV, V, VI, or VII. Digestional analysis with endo- and exoglycosidases showed that hLysII/IV-FUCTVI contains predominantly biantennary complex N-glycans with a variable number of lactosamine repeats; these were terminally sialylated and fucosylated, suggesting the presence of the sLex antigen. In contrast, hLysII/IV-FUCTIII and IV were not terminally sialylated and hLysII/IV-FUCV and VII were not terminally fucosylated. In a static adhesion assay, binding of U937 to activated HUVEC cells was exclusively blocked in the presence of medium supernatant containing hLysII/IV-FUCTVI and by affinity-purified hLysII/IV-FUCTVI. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5179. doi:1538-7445.AM2012-5179