title: Mechanisms of apoptosis on human lens epithelium after ultraviolet light exposure.
abstract: OBJECTIVE
  The purpose of this study is to understand the mechanism of apoptosis occurring on a cultured human lens epithelial cell line after exposure to ultraviolet (UV) light. We intended to confirm the presence of cellular toxicity and apoptosis and to reveal the roles of p53, caspase 3 and NOXA in these processes.
  
  
  METHODS
  Cells were irradiated with an ultraviolet lamp. Cellular toxicity was measured by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Hoechst staining and fluorescent anti-caspase 3 antibodies were used for apoptosis investigation. The quantities of p53, caspase 3, and NOXA were measured by Western blotting for to investigate the apoptosis pathway.
  
  
  RESULTS
  Cellular toxicity on the human lens epithelium markedly increased with time after UV exposure. On Hoechst staining, we found that apoptosis also remarkably increased after exposure to ultraviolet light, compared with a control group. In the immunochemical study using anti-caspase 3 antibodies, active caspase 3 significantly increased after exposure to ultraviolet light. On Western blotting, p53 decreased, while caspase 3 and NOXA increased.
  
  
  CONCLUSIONS
  Exposure of cultured human lens epithelial cell lines to ultraviolet light induces apoptosis, which promotes the expression of NOXA and caspase 3 increases without increasing p53. This may suggest that UV induced apoptosis is caused by a p53-independent pathway in human lens epithelial cells.
authors.affiliation: Department of Ophthalmology, Chosun University School of Medicine, Gwangju, Korea.
authors.forename: Seong-Taeck
authors.initials: ST
authors.lastname: Kim
authors.forename: Jae-Woong
authors.initials: JW
authors.lastname: Koh
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D004847:Epithelial Cells / Q000528:radiation effects; D006801:Humans; D007908:Lens, Crystalline / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: C498702:PMAIP1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D053148:Caspase 3