EGF-Induced Cell Migration Is Mediated by ERK and PI3K/AKT Pathways in Cultured Human Lens Epithelial Cells

Cataract is considered as the most common cause of blindness, which is curable only by surgery. Postsurgery, however, many patients gradually develop the complication of posterior capsule opacification (PCO) or secondary cataract, arising from stimulated cell proliferation and cell migration within the lens capsule. The migration of human lens epithelial cells (HLECs) plays crucial roles in the remodeling of lens capsule and cataract formation, but less is known about the cell-signaling mechanism of migration. We observed that epithelial growth factor (EGF) induced cell migration in cultured human lens epithelial cells through the ERK and PI3K/AKT pathways. EGF induced cell migration in a dose-dependent manner; EGF-induced EGFR phosphorylation and downstream activation of c-Jun N-terminal protein kinase (JNK), p38 MAP kinase (p38), extracellular signal-regulated kinase (ERK1/2) and AKT, were inhibited by PD153035 (EGFR inhibitor), JNKi (JNK inhibitor), SB203580 (p38 inhibitor), U0126 (MEK/ERK inhibitor), and LY294002 (PI3K/AKT inhibitor), respectively. Furthermore, we found that EGF induced activity of matrix metalloproteinase-2 (MMP-2) in cultured HLECs. EGF-induced MMP-2 activity was significantly inhibited by treatment of PD153035, U0126, and LY294002, but not SB203580 and JNK inhibitor, suggesting that ERK and the phosphatidylinositol- 3-kinase (PI3K)/AKT pathways selectively mediate EGF-stimulated MMP-2 activity and cell migration in cultured HLECs in vitro. Taken together, our results suggest that the cell-signaling pathways involved in EGF-stimulated cell migration may constitute potential therapeutic targets in the treatment of PCO.