33 Citations (Scopus)

Abstract

Specific metabolites of estrogens, catechol estrogen-3,4-quinones, if produced in relatively large amounts, can become chemical carcinogens by reacting with DNA to form predominandy depurinating DNA adducts. Estradiol (E2)-3,4-quinone (Q) reacts with DNA to form predominantly the depurinating DNA adducts, 4-hydroxyestradiol (OHE2)-1-N3Ade and 4-OHE2-1-N7Gua. The depurinating adducts induce mutations by error-prone repair. We have conducted a study in which selected natural chemopreventing agents, N-acetylcysteine (NAcCys), melatonin, reduced lipoic acid, and resveratrol, have been tested for their ability to prevent the reaction of E2-3,4-Q with DNA. When DNA was incubated with E 2-3,4-Q or lactoperoxidase-activated 4-OHE2 in the presence of an antioxidant, the formation of the N3Ade and N7Gua adducts was reduced. E2-3,4-Q or lactoperoxidase-oxidized 4-OHE2 (87 μM final concentration) was incubated with calf-thymus DNA and one of the antioxidants at different ratios (1:0, 1:0.3, 1:1, and 1:3 with respect to E2-3,4-Q or 4-OHE2) at 37°C. After 10 h, the DNA was precipitated, and the supernatant was analyzed by using ultraperformance liquid chromatography/tandem mass spectrometry (LC/MS/MS). As anticipated, resveratrol and melatonin did not affect the formation of the depurinating adducts when E2-3,4-Q was reacted with DNA in their presence. On the other hand, NAcCys and lipoic acid (reduced form) showed a significant inhibition of the formation of the depurinating adducts by E2-3,4-Q. With reaction of lactoperoxidase-activated 4-OHE2 with DNA, resveratrol achieved the highest level of inhibition, NAcCys and reduced lipoic acid produced moderate inhibition, and melatonin had the least inhibition. These results demonstrate that all four selected compounds can inhibit the formation of depurinating estrogen-DNA adducts and set the stage for studies of their ability to inhibit adduct formation and malignant transformation in mammary epithelial cells. This approach is highly useful for identifying agents to prevent the initiation of human cancers, especially breast and prostate cancer.

Original languageEnglish (US)
Pages (from-to)1947-1953
Number of pages7
JournalChemical Research in Toxicology
Volume20
Issue number12
DOIs
StatePublished - Dec 1 2007

Fingerprint

DNA Adducts
Estrogens
Lactoperoxidase
DNA
Thioctic Acid
Acetylcysteine
Melatonin
Prostatic Neoplasms
Antioxidants
Breast Neoplasms
Liquid chromatography
Metabolites
Tandem Mass Spectrometry
estradiol-3,4-quinone
Liquid Chromatography
Carcinogens
Mass spectrometry
Estradiol
Breast
Repair

ASJC Scopus subject areas

  • Toxicology

Cite this

Inhibition of depurinating estrogen-DNA adduct formation by natural compounds. / Zahid, Muhammad; Gaikwad, Nilesh W.; Rogan, Eleanor G; Cavalieri, Ercole.

In: Chemical Research in Toxicology, Vol. 20, No. 12, 01.12.2007, p. 1947-1953.

Research output: Contribution to journalArticle

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abstract = "Specific metabolites of estrogens, catechol estrogen-3,4-quinones, if produced in relatively large amounts, can become chemical carcinogens by reacting with DNA to form predominandy depurinating DNA adducts. Estradiol (E2)-3,4-quinone (Q) reacts with DNA to form predominantly the depurinating DNA adducts, 4-hydroxyestradiol (OHE2)-1-N3Ade and 4-OHE2-1-N7Gua. The depurinating adducts induce mutations by error-prone repair. We have conducted a study in which selected natural chemopreventing agents, N-acetylcysteine (NAcCys), melatonin, reduced lipoic acid, and resveratrol, have been tested for their ability to prevent the reaction of E2-3,4-Q with DNA. When DNA was incubated with E 2-3,4-Q or lactoperoxidase-activated 4-OHE2 in the presence of an antioxidant, the formation of the N3Ade and N7Gua adducts was reduced. E2-3,4-Q or lactoperoxidase-oxidized 4-OHE2 (87 μM final concentration) was incubated with calf-thymus DNA and one of the antioxidants at different ratios (1:0, 1:0.3, 1:1, and 1:3 with respect to E2-3,4-Q or 4-OHE2) at 37°C. After 10 h, the DNA was precipitated, and the supernatant was analyzed by using ultraperformance liquid chromatography/tandem mass spectrometry (LC/MS/MS). As anticipated, resveratrol and melatonin did not affect the formation of the depurinating adducts when E2-3,4-Q was reacted with DNA in their presence. On the other hand, NAcCys and lipoic acid (reduced form) showed a significant inhibition of the formation of the depurinating adducts by E2-3,4-Q. With reaction of lactoperoxidase-activated 4-OHE2 with DNA, resveratrol achieved the highest level of inhibition, NAcCys and reduced lipoic acid produced moderate inhibition, and melatonin had the least inhibition. These results demonstrate that all four selected compounds can inhibit the formation of depurinating estrogen-DNA adducts and set the stage for studies of their ability to inhibit adduct formation and malignant transformation in mammary epithelial cells. This approach is highly useful for identifying agents to prevent the initiation of human cancers, especially breast and prostate cancer.",
author = "Muhammad Zahid and Gaikwad, {Nilesh W.} and Rogan, {Eleanor G} and Ercole Cavalieri",
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T1 - Inhibition of depurinating estrogen-DNA adduct formation by natural compounds

AU - Zahid, Muhammad

AU - Gaikwad, Nilesh W.

AU - Rogan, Eleanor G

AU - Cavalieri, Ercole

PY - 2007/12/1

Y1 - 2007/12/1

N2 - Specific metabolites of estrogens, catechol estrogen-3,4-quinones, if produced in relatively large amounts, can become chemical carcinogens by reacting with DNA to form predominandy depurinating DNA adducts. Estradiol (E2)-3,4-quinone (Q) reacts with DNA to form predominantly the depurinating DNA adducts, 4-hydroxyestradiol (OHE2)-1-N3Ade and 4-OHE2-1-N7Gua. The depurinating adducts induce mutations by error-prone repair. We have conducted a study in which selected natural chemopreventing agents, N-acetylcysteine (NAcCys), melatonin, reduced lipoic acid, and resveratrol, have been tested for their ability to prevent the reaction of E2-3,4-Q with DNA. When DNA was incubated with E 2-3,4-Q or lactoperoxidase-activated 4-OHE2 in the presence of an antioxidant, the formation of the N3Ade and N7Gua adducts was reduced. E2-3,4-Q or lactoperoxidase-oxidized 4-OHE2 (87 μM final concentration) was incubated with calf-thymus DNA and one of the antioxidants at different ratios (1:0, 1:0.3, 1:1, and 1:3 with respect to E2-3,4-Q or 4-OHE2) at 37°C. After 10 h, the DNA was precipitated, and the supernatant was analyzed by using ultraperformance liquid chromatography/tandem mass spectrometry (LC/MS/MS). As anticipated, resveratrol and melatonin did not affect the formation of the depurinating adducts when E2-3,4-Q was reacted with DNA in their presence. On the other hand, NAcCys and lipoic acid (reduced form) showed a significant inhibition of the formation of the depurinating adducts by E2-3,4-Q. With reaction of lactoperoxidase-activated 4-OHE2 with DNA, resveratrol achieved the highest level of inhibition, NAcCys and reduced lipoic acid produced moderate inhibition, and melatonin had the least inhibition. These results demonstrate that all four selected compounds can inhibit the formation of depurinating estrogen-DNA adducts and set the stage for studies of their ability to inhibit adduct formation and malignant transformation in mammary epithelial cells. This approach is highly useful for identifying agents to prevent the initiation of human cancers, especially breast and prostate cancer.

AB - Specific metabolites of estrogens, catechol estrogen-3,4-quinones, if produced in relatively large amounts, can become chemical carcinogens by reacting with DNA to form predominandy depurinating DNA adducts. Estradiol (E2)-3,4-quinone (Q) reacts with DNA to form predominantly the depurinating DNA adducts, 4-hydroxyestradiol (OHE2)-1-N3Ade and 4-OHE2-1-N7Gua. The depurinating adducts induce mutations by error-prone repair. We have conducted a study in which selected natural chemopreventing agents, N-acetylcysteine (NAcCys), melatonin, reduced lipoic acid, and resveratrol, have been tested for their ability to prevent the reaction of E2-3,4-Q with DNA. When DNA was incubated with E 2-3,4-Q or lactoperoxidase-activated 4-OHE2 in the presence of an antioxidant, the formation of the N3Ade and N7Gua adducts was reduced. E2-3,4-Q or lactoperoxidase-oxidized 4-OHE2 (87 μM final concentration) was incubated with calf-thymus DNA and one of the antioxidants at different ratios (1:0, 1:0.3, 1:1, and 1:3 with respect to E2-3,4-Q or 4-OHE2) at 37°C. After 10 h, the DNA was precipitated, and the supernatant was analyzed by using ultraperformance liquid chromatography/tandem mass spectrometry (LC/MS/MS). As anticipated, resveratrol and melatonin did not affect the formation of the depurinating adducts when E2-3,4-Q was reacted with DNA in their presence. On the other hand, NAcCys and lipoic acid (reduced form) showed a significant inhibition of the formation of the depurinating adducts by E2-3,4-Q. With reaction of lactoperoxidase-activated 4-OHE2 with DNA, resveratrol achieved the highest level of inhibition, NAcCys and reduced lipoic acid produced moderate inhibition, and melatonin had the least inhibition. These results demonstrate that all four selected compounds can inhibit the formation of depurinating estrogen-DNA adducts and set the stage for studies of their ability to inhibit adduct formation and malignant transformation in mammary epithelial cells. This approach is highly useful for identifying agents to prevent the initiation of human cancers, especially breast and prostate cancer.

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