The epidermal growth factor (EGF) receptor plays a central role in numerous aspects of keratinocyte biology. In normal epidermis, the EGF receptor is important for autocrine growth of this renewing tissue, suppression of terminal differentiation, promotion of cell survival, and regulation of cell mi
Differential response to keratinocyte growth factor receptor and epidermal growth factor receptor ligands of proliferating and differentiating intestinal epithelial cells
✍ Scribed by Vincenzo Visco; Francesca Belleudi; Cinzia Marchese; Laura Leone; Laura Aimati; Giorgia Cardinali; Daniela Kovacs; Luigi Frati; Maria Rosaria Torrisi
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 889 KB
- Volume
- 200
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
Abstract
The expression of the keratinocyte growth factor receptor (KGFR) has been analyzed on intestinal epithelial Caco‐2 cells upon confluence‐induced spontaneous differentiation. Western blot and immunofluorescence analysis showed that the expression of functional KGFRs, differently from that of epidermal growth factor receptor (EGFR), was up‐modulated in post‐confluent differentiated cultures compared with the pre‐confluent cells. Confocal microscopy and immunoelectron microscopy revealed that the up‐regulated KGFRs displayed a basolateral polarized distribution on the cell surfaces in the monolayer. In vivo immunohistochemical analysis on normal human colon tissue sections showed that KGFRs, differently from EGFRs, were mostly distributed on the more differentiated cells located on the upper portion of the intestinal crypt. Bromodeoxyuridine incorporation assay and Ki67 labeling indicated that the differentiated cells were able to proliferate in response to the two ligands of KGFR, KGF and FGF‐10, whereas they were not stimulated by the EGFR ligands TGFα and EGF. Western blot and quantitative immunofluorescence analysis of the expression of carcinoembryonic antigen (CEA) in post‐confluent cells revealed that incubation with KGF induced an increase of cell differentiation. Taken together these results indicate that up‐modulation of KGFR may be required to promote proliferation and differentiation in differentiating cells and that, among the cells componing the intestinal epithelial monolayer, the target cells for KGFR ligands appear to be different during differentiation from those responsive to EGFR ligands. © 2004 Wiley‐Liss, Inc.
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