Identification of estrogen-modified nucleosides from calf thymus DNA reacted with 6-hydroxyestrogen 6-sulfates.
Two estrogen sulfates, pyridinium 3-methoxyestra-1,3, 5(10)-trien-6alpha-yl sulfate (3MeE-6alpha-S) and its 6beta-isomer (3MeE-6beta-S), synthesized as model compounds to demonstrate the carcinogenesis of estrogen, were found to react with calf thymus DNA to produce steroid-modified DNA adducts. Digestion of the DNA by nuclease P1 and phosphodiesterase I followed by alkaline phosphatase gave a deoxyribonucleoside fraction, of which N2-[3-methoxyestra-1,3, 5(10)-trien-6alpha-yl]deoxyguanosine, N2-[3-methoxyestra-1,3, 5(10)-trien-6beta-yl]deoxyguanosine, N6-[3-methoxyestra-1,3, 5(10)-trien-6beta-yl]deoxyadenosine, and N6-[3-methoxyestra-1,3, 5(10)-trien-6alpha-yl]deoxyadenosine (identified as a base adduct) were identified using HPLC by comparing them with authentic specimens prepared by reacting dG and dA with both sulfates. No steroid-dC adduct was detected in the digestion products of the DNA adduct, although dC reacted with the sulfates to form N4-[3-methoxyestra-1,3,5(10)-trien-6beta-yl]deoxycytidine. These results mean that estrogen 6-sulfate has an ability to modify DNA via the amino group of a guanine or adenine residue in DNA. The present studies imply that a sequential metabolism (hydroxylation and sulfation) at the C6-position of the estrogen molecule causes damage to DNA.
Itoh
S
S
Hokkaido College of Pharmacy, 7-1, Katsuraoka-cho, Otaru, Hokkaido 047-0264, Japan.
Hirai
T
T
Totsuka
Y
Y
Takagi
H
H
Tashiro
Y
Y
Wada
K
K
Wakabayashi
K
K
Shibutani
S
S
Yoshizawa
I
I
D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000737:chemistry*; D004249:DNA Damage / Q000187:drug effects; D004967:Estrogens / Q000737:chemistry*; D002393:Estrogens, Catechol / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D009705:Nucleosides / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013950:Thymus Gland / Q000737:chemistry*
C116355:6-hydroxyestrogen 6-sulfate; D004967:Estrogens; D002393:Estrogens, Catechol; D009705:Nucleosides; D004247:DNA