Galectin-3 binding and metastasis

Galectin-3 (gal-3) is a member of a growing family of carbohydrate-binding proteins. It consists of two functional domains: an amino-(N)-terminal domain, which is cleavable by collagenases and is responsible for dimerization as well as secretion of the protein, and a carboxy-(C)-terminal domain with affinity for carbohydrates containing N-acetylactosamine residues. Gal-3 is present in the nucleus, the cytoplasm, and also the extracellular matrix of many normal and neoplastic cell types. However, an array of reports show an up-regulation of this protein in transformed and metastatic cell lines (1,2). Moreover, in many human carcinomas, an increased expression of gal-3 correlates with progressive tumor stages (3,6).