Molecular and Cellular Biochemistry

, Volume 279, Issue 1–2, pp 105–112

Inorganic arsenic compounds cause oxidative damage to DNA and protein by inducing ROS and RNS generation in human keratinocytes



Arsenic is a naturally occurring element that is present in food, soil, and water. Inorganic arsenic can accumulate in human skin and is associated with increased risk of skin cancer. Oxidative stress due to arsenic exposure is proposed as one potential mode of carcinogenic action. The purpose of this study is to investigate the specific reactive oxygen and nitrogen species that are responsible for the arsenic-induced oxidative damage to DNA and protein. Our results demonstrated that exposure of human keratinocytes to trivalent arsenite caused the generation of 8-hydroxyl-2′-deoxyguanine (8-OHdG) and 3-nitrotyrosine (3-NT) in a concentration- and time-dependent manner. Pentavalent arsenate had similar effects, but to a significantly less extent. The observed oxidative damage can be suppressed by pre-treating cells with specific antioxidants. Furthermore, we found that pre-treating cells with Nω-nitro-l-arginine methyl ester (l-NAME), an inhibitor of nitric oxide synthase (NOS), or with 5,10,15,20-tetrakis (N-methyl-4′-pyridyl) porphinato iron (III) chloride (FeTMPyP), a decomposition catalyst of peroxynitrite, suppressed the generation of both 8-OHdG and 3-NT, which indicated that peroxynitrite, a product of the reaction of nitric oxide and superoxide, played an important role in arsenic-induced oxidative damage to both DNA and protein. These findings highlight the involvement of peroxynitrite in the molecular mechanism underlying arsenic-induced human skin carcinogenesis.

Key Words

arsenic DNA damage keratinocytes oxidative stress 


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Copyright information

© Springer Science + Business Media, Inc. 2005

Authors and Affiliations

  1. 1.Program of Toxicology, College of PharmacyUniversity of New Mexico Health Science CenterAlbuquerqueUSA
  2. 2.College of Pharmacy, MSC09 5360University of New MexicoAlbuquerqueUSA

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