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K.–S. Lee, J. Lyu, C.–K. Joo; IGF–1 Activates EGF Receptor in Human Corneal Epithelial Cells . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2116.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Wound healing requires a complex processes to cover defect area and quickly re–establish the barrier function of the injury. These include the proliferation and migration of epithelial cells. The several growth factors involved in corneal wound healing. Insulin–like growth factor 1 (IGF–1) of these factors has been known as a stimulator the proliferation and migration of epithelial cells to coverage the defected area. However, the cellular mechanism that regulates the separated process is unclear. Methods: To investigate the cellular responses for IGF–1 in corneal epithelial cells, we tested the proliferation and migration using the SV40 transformed cells (HCET). HECT cells (4X102) were seed, incubated for 24 hrs in serum free–medium, and treated with IGF–1. The rate of growth was determined by using the Proliferation Reagent WST–1. The migration assays were performed by the 8 mm–pore Tissue Culture Inserts. HCET were treated with IGF–1(50ng/ml) or EGF(25ng/ml), with a neutralizing antibody to anti–EGFR or anti–IGF–1R to establish the intracellular mechanism. Western blotting was then subjected with antibodies to anti–phospho–ERK and anti–phospho–Akt. Results: ERK and AKT were rapidly activated by IGF–1. Interestingly, the activation of ERK was reduced by the inhibition of EGFR, but not by the inhibition of IGF–1R. In contrast, Akt activation was not changed by their inhibition. HCET cells treated with IGF–1 revealed the increased proliferation and migration rate compared with control cells. However, the proliferation and migration caused by IGF–1 showed the different signal pathways. The growth rate of the HCET cells incubated with IGF–1 and a neutralizing antibody to anti–EGFR was decreased compared with cells incubated with IGF–1 and IgG. The migration of HCET cells was regulated by the IGF–1R, rather than EFGR. Conclusions: In this study, we found that IGF activates both IGF–1R and EGFR in corneal epithelial cells, and that IGF can promote the compartmentalized responses through different pathway during wound healing. Our finding provides, to our knowledge, for the first time the dual function of IGF in corneal epithelial cells.
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