Assessment of DNA damage at the dimer level: measurement of the formamide lesion.
UVC-radiation-induced DNA damage was measured in mouse fibroblast cells using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in conjunction with isotopically labeled internal standards. The thymine glycol and formamide lesions were assayed in the form of modified dinucleoside monophosphates. The 8-oxo-7,8-dihydroguanine lesion was measured as the modified nucleoside. DNA damage in cells treated with tirapazamine was also measured. Tirapazamine is a chemotherapeutic agent that acts via a free radical mechanism. The two agents, UVC radiation and tirapazamine, produce markedly different profiles of DNA damage, reflecting their respective mechanisms of action. Both agents produce significant amounts of thymine glycol and formamide damage, but only the former produced a measurable amount of the 8-oxo-7,8-dihydroguanine lesion. The merits of measuring DNA damage at the dimer level are discussed.
Greene
Kellee F
KF
Roswell Park Cancer Institute, Cellular Stress Biology, Buffalo, New York 14263, USA.
Budzinski
Edwin E
EE
Iijima
Herbert
H
Dawidzik
Jean B
JB
DeFedericis
Han-Chun
HC
Patrzyc
Helen B
HB
Evans
Marianne S
MS
Bailey
Douglas T
DT
Freund
Harold G
HG
Box
Harold C
HC
D000818:Animals; D002853:Chromatography, Liquid; D004247:DNA / Q000187:drug effects* / Q000528:radiation effects*; D004249:DNA Damage; D019281:Dimerization; D005347:Fibroblasts / Q000187:drug effects / Q000528:radiation effects; D005559:Formamides / Q000494:pharmacology*; D006147:Guanine / Q000031:analogs & derivatives / Q000494:pharmacology; D013058:Mass Spectrometry; D051379:Mice; D008809:Mice, Inbred C3H; D018384:Oxidative Stress; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology; D000077704:Tirapazamine; D014227:Triazines / Q000494:pharmacology; D014466:Ultraviolet Rays
D005559:Formamides; D011838:Radiation-Sensitizing Agents; D014227:Triazines; D000077704:Tirapazamine; C031066:formamide; C024829:8-hydroxyguanine; D006147:Guanine; D004247:DNA