Formation of 8-hydroxydeoxyguanosine within DNA of mouse keratinocytes exposed in culture to UVB and H2O2

Abstract

Exposure to UV light contributes to the development of skin cancer. The importance of reactive oxygen species in UV-radiation carcinogenesis has been recognized for some time and several associated DNA base modifications have been identified. In particular, 8-hydroxydeoxyguanosine (8-OHdG) has been well studied as an indicator of oxidative damage to calf thymus DNA exposed to a variety of oxygen-generating systems, including UV light. However, to date, few studies of 8-OHdG have been conducted in cell or animal systems and those in vitro investigations that studied UV exposure have used UVC (2 (dose—response range: 210–630 mJ/cm²). UVB exposure at 630 mJ/cm² combined with 5 mM H₂O₂ elevated 8-OHdG formation up to 280% above that in control cells, whereas H₂O₂ alone had no effect. These results suggest that factors which increase the generation of reactive oxygen species by UV light may be potent cofactors of UV-radiation carcinogenesis.