Role of reactive oxygen species in epithelial-mesenchymal transition and apoptosis of human lens epithelial cells

AIM: To investigate the role of reactive oxygen species (ROS) in epithelial-mesenchymal transition (EMT) and apoptosis of human lens epithelial cells (HLECs). METHODS: Flow cytometry was used to assess ROS production after transforming growth factor beta 2 (TGF-beta 2) induction. Apoptosis of HLECs after H2O2 and TGF-beta 2 interference with or without ROS scavenger N-acetylcysteine (NAC) were assessed by flow cytometry. The corresponding protein expression levels of the EMT marker alpha-smooth muscle actin (alpha-SMA), the extracellular matrix (ECM), marker fibronectin (Fn), and apoptosis-associated proteins were detected by using Western blotting in the presence of an ROS scavenger (NAC). Wound-healing and Transwell assays were used to assess the migration capability of HLECs. RESULTS: TGF-beta 2 stimulates ROS production within 8h in HLECs. Additionally, TGF-beta 2 induced HLECs cell apoptosis, EMT/ECM synthesis protein markers expression, and pro-apoptotic proteins production; nonetheless, NAC treatment prevented these responses. Similarly, TGF-beta 2 promoted HLECs cell migration, whereas NAC inhibited cell migration. We further determined that although ROS initiated apoptosis, it only induced the accumulation of the EMT marker alpha-SMA protein, but not COL-1 or Fn. CONCLUSION: ROS contribute to TGF-beta 2-induced EMT/ECM synthesis and cell apoptosis of HLECs; however, ROS alone are not sufficient for EMT/ECM synthesis.