UV Induces Phosphorylation of Protein Kinase B (Akt) at Ser-473 and Thr-308 in Mouse Epidermal C1 41 Cells Through Hydrogen Peroxide

Details

• Personal Author:
  Castranova, Vincent ; Ding M ; Huang C ; Leonard, Stephen S. ; Li J ; Shi X ; Vallyathan V ; Wang L
• Description:
  The exposure of mammalian cells to UV irradiation leads to the activation of transcription factors and protein kinases, which are believed to be responsible for the carcinogenic effects of excessive sun exposure. The present study investigated the effect of UV exposure on reactive oxygen species (ROS) generation and protein kinase B (Akt) phosphorylation in epidermal cells and determined if a relationship exists between these UV responses. Exposure of mouse epidermal JB6 Cl 41 cells to UV radiation led to specific phosphorylation of Akt at Ser-473 and Thr-308 in a time-dependent manner. This phosphorylation was confirmed by the observation that overexpression of Akt mutant, Akt-T308/S473A, attenuated phosphorylation of Akt at Ser-473 and Thr-308. UV radiation also generated ROS as measured by electron spin resonance (ESR) in JB6 Cl 41 cells. The generation of ROS by UV radiation was measured further by H(2)O(2) and O(-.2) fluorescence staining assays. The mechanism of ROS generation involved reduction of molecular oxygen to O(-.2), which generated H(2)O(2) through dismutation. H(2)O(2) produced .OH via a metal-independent pathway. The scavenging of UV-generated H(2)O(2) by N-acety-l-cyteine (NAC, a general antioxidant) or catalase (a specific H(2)O(2) inhibitor) inhibited Akt phosphorylation at Ser-473 and Thr-308, whereas the pretreatment of cells with sodium formate (an .OH radical scavenger) or superoxide dismutase (an O(-.2) radical scavenger) did not show any inhibitory effects. Furthermore, treatment of cells with H(2)O(2) increased UV-induced phosphorylation of Akt at Ser-473 and Thr-308. These results demonstrate that UV radiation generates a whole spectrum of ROS including O(-.2), .OH, and H(2)O(2) and induces phosphorylation of Akt at Ser-473. Among the various ROS, H(2)O(2) seems most potent in mediating UV-induced phosphorylation of Akt at Ser-473 and Thr-308. It is possible that Akt may play a role in the carcinogenesis effects by UV radiation. [Description provided by NIOSH]
• Subjects:
  Animals Carcinogens Environmental Monitoring Laboratories Neoplasms Occupational Health Radiation Safety Skin Skin Diseases Ultraviolet Rays

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• Keywords:
  Animal-studies Exposure-assessment Exposure-levels Exposure-methods Laboratory-animals Laboratory-testing Mammalian-cells Proteins Radiation-detection Radiation-effects Radiation-exposure Radiation-measurement Radiation-monitoring Skin-cancer Skin-exposure Skin-tests Ultraviolet-light Ultraviolet-radiation

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• ISSN:
  0021-9258
• Publisher:
  JBC Papers
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  New York ; OSHA Region 2 ; OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  276
• Issue:
  43
• NIOSHTIC Number:
  nn:20021754
• Citation:
  J Biol Chem 2001 Oct; 276(43):40234-40240
• Contact Point Address:
  NYU, Sch Med, Nelson Inst Environm Med, 550 1St Ave, New York, NY 10016 USA
• Email:
  chuanshu@env.med.nyu.edu
• Federal Fiscal Year:
  2002
• Peer Reviewed:
  True
• Source Full Name:
  Journal of Biological Chemistry
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:b8aea9ccb56e90a30a884b81879fabe0e8e1a23dd369dced2431e50f054af4af9432026c7bd83db21f4c57d534b20cdda2a09ae8e0f32d1dee49d19f1d94af6a
• Download URL:
  https://stacks.cdc.gov/view/cdc/198863/cdc_198863_DS1.pdf
• File Type:
  [PDF - 336.69 KB ]