Epithelial-matrix interactions: Laminin downregulates enterocyte EGF receptor and IGF-I receptor expression

Intestinal crypt cells continuously proliferate to yield functional villus cells which terminally differentiate prior to sloughing into the intestinal lumen. Growth factors and extracellular matrix have been shown to regulate this process. To investigate how these effectors may interact, Epidermal Growth Factor (EGF) receptor and Insulin-like Growth Factor-I (IGF-I) receptor expression was evaluated in IEC-6 cells incubated on laminin or collagen I. EGF receptor and IGF-I receptor expression were decreased in cells grown on laminin. The data suggest that the mechanism by which laminin inhibits enterocyte growth is downregulation of growth factor receptors for important enterocyte mitogens.