Glycosylation-dependent binding of galectin-8 to activated leukocyte cell adhesion molecule (ALCAM/CD166) promotes its surface segregation on breast cancer cells

FERNANDEZ, MM; FERRAGUT, F; CARDENAS, V; BRACALANTE, C; BRAVO, A; CAGNONI, A; NUÑEZ, M; MOROSI, L; HR QUINTÁ; ESPELT, MV; TRONCOSO, MF; WOLFENSTEIN-TODEL, C; MARIÑO, K; MALCHIODI, E; RABINOVICH, GA; ELOLA, MT

BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016

0304-4165

Background: We previously demonstrated that the activated leukocyte cell adhesion molecule(ALCAM/CD166) can interact with galectin-8 (Gal-8) in endothelial cells. ALCAM is a member ofthe immunoglobulin superfamily that promotes homophilic and heterophilic cell-cell interactions.Gal-8 is a ?tandem-repeat?-type galectin, known as a matricellular protein involved in cell adhesion.Here, we analyzed the physical interaction between both molecules in breast cancer cells and thefunctional relevance of this phenomenon.Methods: We performed binding assays by surface plasmon resonance to study the interactionbetween Gal-8 and the recombinant glycosylated ALCAM ectodomain or endogenous ALCAMfrom MDA-MB-231 breast cancer cells. We also analyzed the binding of ALCAM-silenced orcontrol breast cancer cells to immobilized Gal-8 by SPR. In internalization assays, we evaluated theinfluence of Gal-8 on ALCAM surface localization.Results: We showed that recombinant glycosylated ALCAM and endogenous ALCAM from breastcarcinoma cells physically interacted with Gal-8 in a glycosylation-dependent fashion displaying adifferential behavior compared to non-glycosylated ALCAM. Moreover, ALCAM-silenced breastcancer cells exhibited reduced binding to Gal-8 relative to control cells. Importantly, exogenouslyaddedGal-8 provoked ALCAM segregation, probably trapping this adhesion molecule at thesurface of breast cancer cells.Conclusions: Our data indicate that Gal-8 interacts with ALCAM at the surface of breast cancercells through glycosylation-dependent mechanisms.