TY - JOUR
T1 - Formation of 8-hydroxydeoxyguanosine within DNA of mouse keratinocytes exposed in culture to uvb and H2O2
AU - Beehler, Blake C.
AU - Przybyszewski, Joseph
AU - Box, Harold B.
AU - Kulesz-martin, Molly F.
N1 - Funding Information:
We are grateful to Dr Thomas Nicotera for helpful discussion and assistance with the initial configuration and calibration of the electrochemical system. We also appreciate the help of Dr Leslie Blumenson in the statistical analysis of our data. Our thanks to Lori Ratajczak for her excellent secretarial skills in preparing this manuscript. This study was supported by PHS grant NIH CA44808.
PY - 1992/11
Y1 - 1992/11
N2 - 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 (<290 nm), not the UVB (290-320 nm) or UVA (320-400 nm) ranges to which organisms are exposed through sunlight. The objective of this study was to measure 8-OHdG formation in the DNA of cultured mouse keratinocytes exposed to UVB. Using HPLC with electrochemical detection, background levels of 8-OHdG were ∼6 fmol/μg DNA in DNA isolated and digested to the nucleoside level. UVB induced 8-OHdG up to 100% above that for mock-treated cells at a dose of 630 mJ/cm2 (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.
AB - 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 (<290 nm), not the UVB (290-320 nm) or UVA (320-400 nm) ranges to which organisms are exposed through sunlight. The objective of this study was to measure 8-OHdG formation in the DNA of cultured mouse keratinocytes exposed to UVB. Using HPLC with electrochemical detection, background levels of 8-OHdG were ∼6 fmol/μg DNA in DNA isolated and digested to the nucleoside level. UVB induced 8-OHdG up to 100% above that for mock-treated cells at a dose of 630 mJ/cm2 (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.
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U2 - 10.1093/carcin/13.11.2003
DO - 10.1093/carcin/13.11.2003
M3 - Article
C2 - 1423868
AN - SCOPUS:0026443280
SN - 0143-3334
VL - 13
SP - 2003
EP - 2007
JO - Carcinogenesis
JF - Carcinogenesis
IS - 11
ER -