Fibronectin supports bronchial epithelial cell adhesion and survival in the absence of growth factors

Cell-extracellular matrix interactions support the ability of cells to migrate into areas of inflammation and injury. The present study evaluated the ability of different matrix proteins to support bronchial epithelial cell attachment and survival. Collagens were able to support attachment and survival of normal cultured human bronchial epithelial cells but only in the presence of added soluble growth factors such as insulin, epidermal growth factor, platelet-derived growth factor, and bovine pituitary extract. In contrast, fibronectin was able to support attachment and survival of normal human bronchial epithelial cells in growth factor-deficient medium. In addition, fibronectin, in the absence of added growth factors, was able to induce integrin clustering, focal adhesion formation, and phosphorylation of focal adhesion kinase. A 120-kDa chymotryptic fragment of fibronectin containing the Arg-Gly-Asp peptide sequence was able to reproduce the effects of the whole fibronectin molecule. This study supports the concept that fibronectin has specialized roles in injury and repair.