TY - JOUR
T1 - Metabolism and DNA binding studies of 4-hydroxyestradiol and estradiol-3,4-quinone in vitro and in female ACI rat mammary gland in vivo
AU - Li, Kai Ming
AU - Todorovic, Rosa
AU - Devanesan, Prabu
AU - Higginbotham, Sheila
AU - Köfeler, Harald
AU - Ramanathan, Ragulan
AU - Gross, Michael L.
AU - Rogan, Eleanor G.
AU - Cavalieri, Ercole L.
N1 - Funding Information:
This research was supported by US Public Health Service grants P01 CA49210 and R01 CA49917 from the National Cancer Institute. Core support at the Eppley Institute was provided by grant P30 CA36727 from the National Cancer Institute. The Washington University Mass Spectrometry Laboratory is supported by grant P41 RR00954 from the National Center for Research Resources of the National Institutes of Health.
PY - 2004/2
Y1 - 2004/2
N2 - Studies of estrogen metabolism, formation of DNA adducts, carcinogenicity, cell transformation and mutagenicity have led to the hypothesis that reaction of certain estrogen metabolites, predominantly catechol estrogen-3,4-quinones, with DNA can generate the critical mutations initiating breast, prostate and other cancers. The endogenous estrogens estrone (E1) and estradiol (E2) are oxidized to catechol estrogens (CE), 2- and 4-hydroxylated estrogens, which can be further oxidized to CE quinones. To determine possible DNA adducts of E1(E2)-3,4-quinones [E1(E2)-3,4-Q], we reported previously that the reaction of E1(E2)-3,4-Q with dG produces the depurinating adduct 4-hydroxyE1(E2)-1-N7Gua [4-OHE1(E2)-1-N7Gua] by 1,4-Michael addition (Stack et al., Chem. Res. Toxicol., 1996, 9, 851). We report here that reaction of E1(E2)-3,4-Q with Ade results in the formation of 4-OHE1(E2)-1-N3Ade by 1,4-Michael addition. The N7Gua and N3Ade depurinating adducts formed both in vitro and in rat mammary gland in vivo were analyzed by HPLC with electrochemical detection and, for some samples, by LC/MS/MS. When E2-3,4-Q was reacted with DNA in vitro, the depurinating adducts 4-OHE1(E2)-1-N3Ade and 4-OHE1(E2)-1-N7Gua, which are rapidly lost from DNA by cleavage of the glycosyl bond, were formed (>99% of the total adducts), as well as traces of stable adducts, which remain in DNA unless removed by repair. Similar results were obtained when 4-OHE2 was oxidized by horseradish peroxidase, lactoperoxidase, tyrosinase or phenobarbital-induced rat liver microsomes in the presence of DNA. When 4-OHE2 or E2-3,4-Q was injected into the mammary glands of female ACI rats in vivo and the mammary tissue was excised 1 h later, the depurinating adducts 4-OHE2-1-N3Ade and 4-OHE2-1-N7Gua constituted >99% of the total adducts formed. In addition, 4-OHE2 conjugates formed by reaction of E2-3,4-Q with glutathione were also detected. These results demonstrate that the 4-CE are metabolized to CE-3,4-Q, which react with DNA to form primarily depurinating adducts. These adducts can generate the critical mutations that initiate cancer (Chakravarti et al., Oncogene, 2001, 20, 7945; Chakravarti et al., Proc. Am. Assoc. Cancer Res., 2003, 44, 180).
AB - Studies of estrogen metabolism, formation of DNA adducts, carcinogenicity, cell transformation and mutagenicity have led to the hypothesis that reaction of certain estrogen metabolites, predominantly catechol estrogen-3,4-quinones, with DNA can generate the critical mutations initiating breast, prostate and other cancers. The endogenous estrogens estrone (E1) and estradiol (E2) are oxidized to catechol estrogens (CE), 2- and 4-hydroxylated estrogens, which can be further oxidized to CE quinones. To determine possible DNA adducts of E1(E2)-3,4-quinones [E1(E2)-3,4-Q], we reported previously that the reaction of E1(E2)-3,4-Q with dG produces the depurinating adduct 4-hydroxyE1(E2)-1-N7Gua [4-OHE1(E2)-1-N7Gua] by 1,4-Michael addition (Stack et al., Chem. Res. Toxicol., 1996, 9, 851). We report here that reaction of E1(E2)-3,4-Q with Ade results in the formation of 4-OHE1(E2)-1-N3Ade by 1,4-Michael addition. The N7Gua and N3Ade depurinating adducts formed both in vitro and in rat mammary gland in vivo were analyzed by HPLC with electrochemical detection and, for some samples, by LC/MS/MS. When E2-3,4-Q was reacted with DNA in vitro, the depurinating adducts 4-OHE1(E2)-1-N3Ade and 4-OHE1(E2)-1-N7Gua, which are rapidly lost from DNA by cleavage of the glycosyl bond, were formed (>99% of the total adducts), as well as traces of stable adducts, which remain in DNA unless removed by repair. Similar results were obtained when 4-OHE2 was oxidized by horseradish peroxidase, lactoperoxidase, tyrosinase or phenobarbital-induced rat liver microsomes in the presence of DNA. When 4-OHE2 or E2-3,4-Q was injected into the mammary glands of female ACI rats in vivo and the mammary tissue was excised 1 h later, the depurinating adducts 4-OHE2-1-N3Ade and 4-OHE2-1-N7Gua constituted >99% of the total adducts formed. In addition, 4-OHE2 conjugates formed by reaction of E2-3,4-Q with glutathione were also detected. These results demonstrate that the 4-CE are metabolized to CE-3,4-Q, which react with DNA to form primarily depurinating adducts. These adducts can generate the critical mutations that initiate cancer (Chakravarti et al., Oncogene, 2001, 20, 7945; Chakravarti et al., Proc. Am. Assoc. Cancer Res., 2003, 44, 180).
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U2 - 10.1093/carcin/bgg191
DO - 10.1093/carcin/bgg191
M3 - Article
C2 - 14578156
AN - SCOPUS:1242353081
SN - 0143-3334
VL - 25
SP - 289
EP - 297
JO - Carcinogenesis
JF - Carcinogenesis
IS - 2
ER -