Role of Cell Surface Proteoglycans in Tumor Cell Recognition of Fibronectin

• Published in: Trends in Glycoscience and Glycotechnology Vol. 6; no. 27; pp. 1 - 16
• Main Authors: Iida, J., Milius, R.P., Oegema, T.R., Furcht, L.T., McCarthy, J.B.
• Format: Journal Article
• Language: English
• Published: FCCA(Forum: Carbohydrates Coming of Age) 1994
• Subjects: cell adhesion; fibronectin; proteoglycans; tumor cell; α4β1 integrin receptor
• ISSN: 0915-7352; 1883-2113
• DOI: 10.4052/tigg.6.1

Cell surface proteoglycans (PGs) play key roles in several aspects of cell behavior, including modulating responses to growth and differentiation factors and modulating cell adhesion and migration. Cell surface PGs are similar to their ECM counterparts, in the sense that they consist of core proteins that contain one to several glycosaminoglycans. One of the most striking features of cell surface PGs as a group is their structural diversity, both from the standpoint of the glycosaminoglycans and from the standpoints of the different core proteins that can be expressed as PGs. This purpose of this brief review is to summarize some of the evidence implicating an important role for cell surface PG in mediating cell adhesion to components of the ECM. The approach is to briefly review some of what is known regarding the structure and function of cell surface PGs, and to discuss this information with respect to integrin mediated cell adhesion, using fibronectin as a prototype ECM component. Collectively, much of the data suggest that cell surface PGs modulate cell adhesion to the ECM by acting in conjunction with other cell adhesion receptors such as integrins. Since fibronectin has multiple closely spaced cellular recognition sites that can bind cell surface PGs and integrin, a working model for cell adhesion to fibronectin is presented in which these sites act in conjunction with one another to cluster cell surface PGs and integrins on the cell surface, creating the necessary signals to promote adhesion. This working model can serve as a conceptual base from which to partially explain mechanism(s) by which fibronectin and other ECM components could transmit information into cells, and it has direct implications in helping to explain cell type-specific behavior associated with many pathological states, including tumor cell invasion and metastasis.