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

FERNÁNDEZ MARISA MARIEL; FERRAGUT F T; CÁRDENAS DELGADO VM; BRACALENTE CT; BRAVO A; CAGNONID A; MOROSIF L; QUINTA H; ESPELT MV; TRONCOSO MF; WOLFENSTEIN-TODEL C; MARIÑO K; MALCHIODI E.L; RABINOVICH G; 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 isa member of the immunoglobulin superfamily that promotes homophilic and heterophiliccell-cell interactions. Gal-8 is a ?tandem-repeat?-typegalectin, known as a matricellular protein involved in cell adhesion. Here, weanalyzed the physical interaction between both molecules in breast cancer cellsand the functional relevance of this phenomenon..Methods: We performed binding assays by surface plasmonresonance to study the interaction between Gal-8 and the ALCAM fully-glycosylatedectodomain or endogenous ALCAM from breast cancer cells. We also analyzed bindingof ALCAM-silenced or control breast cancer cells to immobilized Gal-8 by SPR.In internalization assays, we evaluated the influence of Gal-8 in ALCAM endocytosis.Results: We showed that fully-glycosylated recombinant ALCAM andendogenous ALCAM from breast carcinoma cells physically interact with Gal-8 in a glycosylation-dependentfashion displaying a differential behavior compared to non-glycosylated ALCAM. Moreover,ALCAM-silenced breast cancer cells exhibited reduced binding to Gal-8 relativeto control cells. Importantly, Gal-8 prevented ALCAM internalization bytrapping this receptor at the cell surface.Conclusions: Our data indicate that Gal-8interacts with ALCAM at the surface of breast cancer cells to modulate  its internatization throughglycosylation-dependent mechanisms.General Significance: A novel heterophilicinteraction between ALCAM and Gal-8 is demonstrated here, suggesting itsphysiologic relevance in  the biology ofbreast cancer cells.Keywords: ALCAM/CD166 / breast cancer cell / galectin-8 /physical interaction / lattices