title: Blue light activates phase 2 response proteins and slows growth of a431 epidermoid carcinoma xenografts.
abstract: BACKGROUND
  Recent studies suggest that light in the UVA range (320-400 nm) activates signaling pathways that are anti-inflammatory, antioxidative and play a critical role in protection against cancer. These effects have been attributed to NF-E2-related factor (NRF2)-mediated up-regulation of 'phase 2' genes that neutralize oxidative stress and metabolize electrophiles. We had previously shown that small doses of blue light (400-500 nm) had selective toxicity for cultured oral tumor cells and increased levels of peroxiredoxin phase 2 proteins, which led to our hypothesis that blue light activates NRF2 signaling.
  
  
  METHODS
  A431 epidermoid carcinoma cells were treated in culture and as nude mouse xenografts with doses of blue light. Cell lysates and tumor samples were tested for NRF2 activation, and for markers of proliferation and oxidative stress.
  
  
  RESULTS
  Blue light activated the phase 2 response in cultured A431 cells and reduced their viability dose dependently. Light treatment of tumors reduced tumor growth, and levels of proliferating cell nuclear antigen (PCNA), and oxidized proteins.
  
  
  CONCLUSIONS
  Cellular responses to these light energies are worth further study and may provide therapeutic interventions for inflammation and cancer.
authors.affiliation: Department of Oral Biology, Georgia Regents University, Augusta, GA, U.S.A. Division of Orthodontics, The Ohio State University, Columbus, OH, U.S.A.
authors.forename: Alpesh D
authors.initials: AD
authors.lastname: Patel
authors.affiliation: Department of Oral Biology, Georgia Regents University, Augusta, GA, U.S.A. Division of Periodontics, The Ohio State University, Columbus, OH, U.S.A.
authors.forename: Shaun
authors.initials: S
authors.lastname: Rotenberg
authors.affiliation: Department of Oral Biology, Georgia Regents University, Augusta, GA, U.S.A.
authors.forename: Regina L W
authors.initials: RL
authors.lastname: Messer
authors.affiliation: Department of Oral Biology, Georgia Regents University, Augusta, GA, U.S.A. Department of Restorative Dentistry, University of Washington, Seattle, WA, U.S.A.
authors.forename: John C
authors.initials: JC
authors.lastname: Wataha
authors.affiliation: Department of Oral Biology, Georgia Regents University, Augusta, GA, U.S.A. Department of Diagnostic and Biomedical Sciences, University of Texas School of Dentistry at Houston, Houston, TX, U.S.A.
authors.forename: Kalu U E
authors.initials: KU
authors.lastname: Ogbureke
authors.affiliation: Department of Oral Biology, Georgia Regents University, Augusta, GA, U.S.A.
authors.forename: Veronica V
authors.initials: VV
authors.lastname: McCloud
authors.affiliation: Department of Oral Biology, Georgia Regents University, Augusta, GA, U.S.A.
authors.forename: Petra
authors.initials: P
authors.lastname: Lockwood
authors.affiliation: Department of Oral Biology, Georgia Regents University, Augusta, GA, U.S.A.
authors.forename: Stephen
authors.initials: S
authors.lastname: Hsu
authors.affiliation: Department of Oral Biology, Georgia Regents University, Augusta, GA, U.S.A. College of Dental Medicine, Western University of Health Sciences, Pomona, CA, U.S.A. lewisj@westernu.edu.
authors.forename: Jill B
authors.initials: JB
authors.lastname: Lewis
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology* / Q000532:radiotherapy; D049109:Cell Proliferation / Q000528:radiation effects*; D005260:Female; D051547:Heme Oxygenase-1 / Q000378:metabolism*; D006801:Humans; D008027:Light; D051379:Mice; D008819:Mice, Nude; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: D051267:NF-E2-Related Factor 2; D018809:Proliferating Cell Nuclear Antigen; D051547:Heme Oxygenase-1
keywords: NRF2; blue light; heme oxygenase; oxidative stress; xenograft