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

FERRAGUT, FÁTIMA; FERNÁNDEZ, MARISA M.; CÁRDERAS DELGADO, VICTOR M.; BRACALENTE, CANDELARIA; BRAVO, ALICIA I.; CAGNONI, ALEJANDO J.; NUÑEZ, MYRIAM; MOROSI, LUCIANO; QUINTA, HÉCTOR R.; ESPELT, MARÍA V.; TRONCOSO, MARÍA F.; WOLFENSTEIN-TODEL, CARLOTA; MARIÑO, KARINA V.; MALCHIODI, EMILIO L.; RABINOVICH, GABRIEL A.; ELOLA, MARÍA T.

BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 p. 2255 - 2268

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 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. Methods: We 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.Results: We 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.Conclusions: Our data indicate that Gal-8 interacts with ALCAM at the surface of breast cancer cells through glycosylation-dependent mechanisms. General significance: A novel heterophilic interaction between ALCAM and Gal-8 is demonstrated here, suggesting its physiologic relevance in the biology of breast cancer cells.