TY - JOUR
T1 - Oxidative DNA adducts detected in vitro from redox activity of cigarette smoke constituents
AU - Vadhanam, Manicka V.
AU - Thaiparambil, Jose
AU - Gairola, C. Gary
AU - Gupta, Ramesh C.
PY - 2012/11/19
Y1 - 2012/11/19
N2 - Cigarette smoke contains a variety of carcinogens, cocarcinogens, mutagens, and tumor promoters. In addition to polycyclic aromatic carcinogens and tobacco-specific nitrosamines, cigarette smoke also contains an abundance of catechols, aldehydes, and other constituents, which are DNA damaging directly or indirectly; therefore, they can also contribute to cigarette smoke-mediated carcinogenicity. In this study, we investigated the potential of cigarette smoke constituents to induce oxidative damage to DNA through their capacity to redox cycle. When DNA (300 μg/mL) was incubated with cigarette smoke condensate (0.2 mg of tobacco particulate matter/mL) and CuCl2 as a catalyst (50-100 μM), a variety of oxidative DNA adducts were detected by 32P-postlabeling/TLC. Of the total adduct burden (2114 ± 419 adducts/106 nucleotides), over 40% of all adducts were attributed to the benchmark oxidative DNA lesion, 8-oxodeoxyguanosine (8-oxodG). Adducts were formed dose dependently. Essentially, similar adduct profiles were obtained when cigarette smoke condensate was substituted with ortho- and para- dihydroxybenzenes. Vehicle treatment with Cu2+ or CSC alone did not induce any significant amount of oxidative DNA damage. Furthermore, coincubation of cigarette smoke condensate and ortho-dihydroxybenzene with DNA resulted in a higher amount of oxidative DNA adducts than obtained with the individual entity, suggesting that adducts presumably originated from catechols or catechol-like compounds in cigarette smoke condensate. Adducts resulting from both cigarette smoke condensate and pure dihydroxybenzenes were chromatographically identical to adducts formed by reaction of DNA with H 2O2, which is known to produce 8-oxodG, and many other oxidative DNA adducts. When the cigarette smoke condensate-DNA reaction was performed in the presence of ellagic acid, a known antioxidant, the adduct formation was inhibited dose dependently, further suggesting that adducts originated from oxidative pathway. Our data thus provide evidence of the capacity of catechols or catechol-like constituents in cigarette smoke to produce oxidative DNA damage, which may contribute to the tumor-promoting activity of cigarette smoke.
AB - Cigarette smoke contains a variety of carcinogens, cocarcinogens, mutagens, and tumor promoters. In addition to polycyclic aromatic carcinogens and tobacco-specific nitrosamines, cigarette smoke also contains an abundance of catechols, aldehydes, and other constituents, which are DNA damaging directly or indirectly; therefore, they can also contribute to cigarette smoke-mediated carcinogenicity. In this study, we investigated the potential of cigarette smoke constituents to induce oxidative damage to DNA through their capacity to redox cycle. When DNA (300 μg/mL) was incubated with cigarette smoke condensate (0.2 mg of tobacco particulate matter/mL) and CuCl2 as a catalyst (50-100 μM), a variety of oxidative DNA adducts were detected by 32P-postlabeling/TLC. Of the total adduct burden (2114 ± 419 adducts/106 nucleotides), over 40% of all adducts were attributed to the benchmark oxidative DNA lesion, 8-oxodeoxyguanosine (8-oxodG). Adducts were formed dose dependently. Essentially, similar adduct profiles were obtained when cigarette smoke condensate was substituted with ortho- and para- dihydroxybenzenes. Vehicle treatment with Cu2+ or CSC alone did not induce any significant amount of oxidative DNA damage. Furthermore, coincubation of cigarette smoke condensate and ortho-dihydroxybenzene with DNA resulted in a higher amount of oxidative DNA adducts than obtained with the individual entity, suggesting that adducts presumably originated from catechols or catechol-like compounds in cigarette smoke condensate. Adducts resulting from both cigarette smoke condensate and pure dihydroxybenzenes were chromatographically identical to adducts formed by reaction of DNA with H 2O2, which is known to produce 8-oxodG, and many other oxidative DNA adducts. When the cigarette smoke condensate-DNA reaction was performed in the presence of ellagic acid, a known antioxidant, the adduct formation was inhibited dose dependently, further suggesting that adducts originated from oxidative pathway. Our data thus provide evidence of the capacity of catechols or catechol-like constituents in cigarette smoke to produce oxidative DNA damage, which may contribute to the tumor-promoting activity of cigarette smoke.
UR - http://www.scopus.com/inward/record.url?scp=84869380738&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84869380738&partnerID=8YFLogxK
U2 - 10.1021/tx300312f
DO - 10.1021/tx300312f
M3 - Article
C2 - 22994544
AN - SCOPUS:84869380738
SN - 0893-228X
VL - 25
SP - 2499
EP - 2504
JO - Chemical Research in Toxicology
JF - Chemical Research in Toxicology
IS - 11
ER -