The anti-proliferative action of transforming growth factor-β1 on a rat intestinal epithelial cell line (rie-1) is dependent on cell population density and culture passage number

The migration of intestinal cells is important in the development and maintenance of normal epithelium, in a process that may be regulated by growth factors and cytokines. Although a number of growth factor receptors are expressed by intestinal cells, little progress has been made toward assignment of functional roles for these ligand-receptor systems. This study compares several growth factors and cytokines for their chemoattraction of the mouse small intestinal epithelial cell line. Epidermal and hepatocyte growth factors stimulated a rapid 30-fold chemotaxis of cells with delayed threefold migration toward transforming growth factor-β1. Despite stimulating proliferation, keratinocyte, fibroblast, or insulin-like growth factors did not stimulate directed migration. Chemotaxis required tyrosine kinase and phosphatidylinositol phospholipase C activities but not protein kinase C or mitogen-activated protein kinase activity. These findings suggest that the repertoire of growth factors capable of regulating directed intestinal epithelial cell migration is limited and that a divergence exists in the signal transduction pathways for directed vs. nondirected migration.

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Functional receptors for epidermal growth factor in an epithelial-cell line derived from the rat small intestine

Biochemical Journal ◽

10.1042/bj2250085 ◽

1985 ◽

Vol 225 (1) ◽

pp. 85-94 ◽

Cited By ~ 45

Author(s):

J Blay ◽

K D Brown

Keyword(s):

Growth Factor ◽

Epithelial Cell ◽

Epidermal Growth Factor ◽

Cell Line ◽

Intestinal Epithelial Cell ◽

Epithelial Cell Line ◽

Maximal Effect ◽

Intestinal Epithelial ◽

Egf Receptors ◽

Epidermal Growth

Epidermal growth factor (EGF) regulates the proliferation of cells of a rat intestinal epithelial-cell line (RIE-1) in culture. Confluent RIE-1 cells were stimulated to proliferate by EGF with a half-maximal effect at 1-2 ng/ml. In contrast, the growth of sparse RIE-1 cells was inhibited by the growth factor. Binding studies at 4 degrees C with 125I-EGF identified two classes of binding sites for EGF on RIE-1 cells, one of high affinity (KD = 1.8 × 10(-10)M; 1.8 × 10(4) receptors/cell) and one of lower affinity (KD = 5.2 × 10(-9)M; 6.3 × 10(4) receptors/cell). After binding to the cells at 37 degrees C, 125I-EGF was rapidly internalized and subsequently degraded. Degradation products were released into the medium after a lag of 15-30 min. The degradation of 125I-EGF did not occur at 4 degrees C and was inhibited at 37 degrees C by chloroquine, methylamine or NH4Cl, but not by colchicine. Exposure of RIE-1 cells to EGF caused a time- and dose-dependent loss of EGF receptors from the cell surface. The recovery of receptors after the removal of EGF was retarded in the absence of serum and prevented by the presence of cycloheximide or actinomycin D. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis separation of the 125I-EGF-receptor complex from RIE-1 cells after covalently cross-linking with disuccinimidyl suberate indicated a receptor of Mr congruent to 160 000. The demonstration of functional EGF receptors in this cell line provides further evidence that EGF may regulate intestinal-epithelial-cell physiology.

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