REGULATION OF NORMAL AND TRANSFORMED TRACHEOBRONCHIAL EPITHELIAL-CELL PROLIFERATION BY AUTOCRINE GROWTH-FACTORS

Several peptide growth factors have been identified as autocrine regulators of normal tracheobronchial epithelial cells, including the transforming growth factors alpha and beta. Using in vitro tissue culture models of multistep neoplastic transformation as well as cell lines derived from human bronchogenic tumors, a significant number of growth factors have been found to function as autocrine factors for neoplastic tracheobronchial cells as well. In several instances, the regulation of the autocrine pathway is disrupted in neoplastic tracheobroncial cells compared with their normal counterparts. These results indicate that there are multiple aberrations in growth factor pathways occurring in tracheobronchial epithelial cells during progression to the neoplastic phenotype.