Integrinβ 1-mediated signaling is involved in transforming growth factor-β 2-promoted migration in human lens epithelial cells

Purpose: Transforming growth factor-beta 2 (TGF-beta 2) is a potent growth inhibitor and apoptosis inducer. However, typically TGF-beta 2 loses its growth-inhibitory and apoptosis-inducing effects but stimulates the migratory capacity of epithelial cells. In this study, we investigate the possible involvement of integrin and integrin-mediated signaling in TGF-beta 2-promoted migration and adhesion in human lens epithelial cells. Methods: A human lens epithelial cell line (HLE B-3) was treated with 100 pg/ml TGF-beta 2 for 6 h, 12 h, and 24 h. In vitro wound healing assay and cell adhesion assay were performed to detect the effect of TGF-beta 2 on HLEC adhesion and migration. Integrin beta 1 expression changes in HLECs during the treatment of TGF-beta 2 were detected in protein levels and mRNA levels using confocal microscopy, flow cytometric analysis, and real time quantitative reverse transcription polymerase chain reaction (RT-PCR). Focal adhesion kinase (FAK) activity was examined by FAK phosphorylation and total tyrosine phosphorylation during treatment with TGF-beta 2 in HLEC. Production of endogenous TGF-beta 2 was measured by ELISA assay. Results: In this study, we found that TGF-beta 2 significantly stimulated cell adhesion and migration in HLECs. By immunofluorescence staining and western blotting, we observed that TGF-beta 2 markedly enhanced the expression of integrin beta 1 and the Tyr-phosphorylation of focal adhesion kinase (FAK). Real time quantitative RT-PCR also showed the mRNA level of integrin beta 1 was upregulated. Neutralizing anti-integrin beta 1 monoclonal antibody significantly (p < 0.05) inhibited TGF-beta 2-promoted HLEC adhesion and migration. Conclusions: TGF-beta 2 promoted HLEC adhesion and migration in vitro. Integrin beta 1 and integrin-mediated signaling are necessary for TGF-beta 2-promoted adhesion and migration in human lens epithelial cells.