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

MARISA M. FERNÁNDEZ; FÁTIMA FERRAGUT; VICTOR M. CÁRDENAS DELGADO; CANDELARIA BRACALENTE; ALICIA I BRAVO; ALEJANDRO J. CAGNONI; MYRIAM NÚÑEZ; LUCIANO MOROSI; HECTOR R QUINTA; MARÍA V ESPELT; MARÍA FERNANDA TRONCOSO; CARLOTA WOLFESTEIN-TODEL; MARIÑO, KARINA V.; EMILIO MAICHIODI; RABINOVICH, GABRIEL ADRIÁN; MARIA TERESA ELOLA

BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016

0304-4165

BackgroundWe 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 of the 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 the functional relevance of this phenomenon.MethodsWe performed binding assays by surface plasmon resonance to study the interaction between Gal-8 and the recombinant glycosylated ALCAM ectodomain or endogenous ALCAM from MDA-MB-231 breast cancer cells. We also analyzed the binding of ALCAM-silenced or control breast cancer cells to immobilized Gal-8 by SPR. In internalization assays, we evaluated the influence of Gal-8 on ALCAM surface localization.ResultsWe showed that recombinant glycosylated ALCAM and endogenous ALCAM from breast carcinoma cells physically interacted with Gal-8 in a glycosylation-dependent fashion displaying a differential behavior compared to non-glycosylated ALCAM. Moreover, ALCAM-silenced breast cancer cells exhibited reduced binding to Gal-8 relative to control cells. Importantly, exogenously-added Gal-8 provoked ALCAM segregation, probably trapping this adhesion molecule at the surface of breast cancer cells.ConclusionsOur data indicate that Gal-8 interacts with ALCAM at the surface of breast cancer cells through glycosylation-dependent mechanisms.General SignificanceA novel heterophilic interaction between ALCAM and Gal-8 is demonstrated here, suggesting its physiologic relevance in the biology of breast cancer cells.