Insulin-like growth factor-1 induces migration and expression of laminin-5 in cultured human corneal epithelial cells.
OBJECTIVE
The effects of insulin-like growth factor (IGF)-1 on laminin (Ln)-5 and the associated integrins during in vitro HCEC migration were examined. Also investigated were the effects of IGF-1 on the migration of human corneal epithelial cells (HCECs).


METHODS
HCEC migration was examined by wound-healing and chemoattraction assays. For migration inhibition assays, HCECs were pretreated with inhibitors of the IGF-1 receptor (alphaIR3), the PI3-K/AKT pathway (LY294002), and the MEK-ERK pathway (PD98059). The expression levels of Ln-5 and fibronectin (Fn) were determined by Western blot analysis, and the expression levels of the beta1 and alpha3 integrins were determined by confocal microscopy and Western blot analysis. The migration inhibition with anti-integrin alpha3 and beta1 antibodies was also determined.


RESULTS
HCEC migration was significantly increased in the presence of IGF-1 and Ln-5. IGF-1 enhanced the production of Ln-5 in both a dose- and time-dependent manner, and this upregulation was blocked by pretreatment with alphaIR3 or LY294002. IGF-1 treatment upregulated expression of beta1 integrin, but not alpha3 integrin. The HCEC migration facilitated by IGF-1 was inhibited with the anti-integrin antibody for beta1. However, there was no cross-talk between Ln-5 and integrin beta1 production.


CONCLUSIONS
The results reveal that IGF-1 induces HCEC migration through the independent production of Ln-5 and beta1 integrin, which are directed at least in part by activation of the PI3-K/AKT pathway, but are not affected by the MEK-ERK pathway.
Lee
Hyung Keun
HK
Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
Lee
Joon H
JH
Kim
Min
M
Kariya
Yoshinobu
Y
Miyazaki
Kaoru
K
Kim
Eung Kweon
EK
D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000096:biosynthesis*; D002465:Cell Movement / Q000187:drug effects*; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D019573:Epithelium, Corneal / Q000166:cytology* / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D019012:Integrin beta1 / Q000096:biosynthesis; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009025:Morpholines / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors; D015854:Up-Regulation; D000097794:Kalinin
D015815:Cell Adhesion Molecules; D002867:Chromones; D005419:Flavonoids; D007334:Insulin-Like Growth Factor I; D019012:Integrin beta1; D009025:Morpholines; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017526:Receptor, IGF Type 1; D000097794:Kalinin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one