Integral Membrane Adhesion Glycoproteins: What is their Fate During Metastasis?

Abstract

Data from a large number of laboratories over several decades have shown that adhesive interactions among cells and between cells and extracellular matrix (ECM) are essential to early cell lineage segregation, cell recognition, cell migration and maintenance of normal tissue architecture in the adult. Adhesive interactions are also a fundamental feature of the complex metastatic process. Part of the job of understanding both normal and aberrant adhesive behavior is very basic: identification of the molecules involved at adhesion sites. This job is becoming increasingly complicated for several reasons. We have learned that any one cell type has the ability to adhere to more than one type of extracellular matrix ligand (1, 2) and that cells can adhere to one another not by one, but by several kinds of adhesive complexes (reviewed in 3). Thus, the cells of mature tissues appear to express a repertoire of adhesive molecules. In several well-documented situations, it is clear that the repertoires of different tissue types are distinct. For example, nervous tissue expresses calcium dependent and independent cell-cell adhesion molecules that are distinguishable from analagous molecules expressed by epithelial or connective tissue cells (4, 5, 6, 7).

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