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

FERNÁNDEZ MM ; FERRAGUT F; CÁRDENAS DELGADO VM; BRACALENTE C; BRAVO AI; CAGNONI AJ; NUÑEZ M; MOROSI LG; QUINTA HR; ESPELT MV; TRONCOSO MF; WOLFENSTEIN-TODEL C; MARIÑO KV; MALCHIODI EL; RABINOVICH GA; ELOLA MT

BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 1860 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.Methods: We performed binding assays by surface plasmon resonance to study the interaction between ALCAM fully-glycosylated ectodomain or endogenous ALCAM from breast cancer cells with Gal-8. 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 in ALCAM endocytosis.Results: We showed that recombinant fully-glycosylated ALCAM and endogenous ALCAM from breast carcinoma cells physically interacted with Gal-8 in a glycan-dependent fashion and displayed 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, Gal-8 prevented ALCAM internalization by trapping this receptor at the cell surface.Conclusions: Our data indicate that ALCAM and Gal-8 interact at the surface of breast cancer cells.General Significance: A novel ALCAM heterophilic interaction with Gal-8 and its physiological relevance are demonstrated at the surface of breast cancer cells.