Role of cytochrome P450 enzyme induction in the metabolic activation of benzo[c]phenanthrene in human cell lines and mouse epidermis

Heidi J. Einolf, William T. Story, Craig B. Marcus, Michele C. Larsen, Colin R. Jefcoate, William F. Greenlee, Haruhiko Yagi, Donald M. Jerina, Shantu Amin, Sang S. Park, Harry V. Gelboin, William M. Baird

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Abstract

The environmental contaminant benzo[c]phenanthrene (B[c]Ph) has weak carcinogenic activity in rodent bioassays; however, the fjord region diol epoxides of B[c]Ph, B[c]Ph-3,4-diol 1,2-epoxides (B[c]PhDE), are potent carcinogens. To determine the role of cytochrome P450 isozymes in the activation of B[c]Ph in MCF-7 cells and the low activation of B[c]Ph in mouse skin, cells of the MCF-7 and the human hepatoma HepG2 cell lines were treated with the potent Ah receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) prior to exposure to B[c]Ph for 24 h. Mice were treated topically with 1/μg of TCDD or vehicle (control) for 73 h and then with 2/μmol of B[c]Ph for 24 h. In MCF-7 cells, TCDD exposure increased B[c]PhDE-DNA adduct levels more than 3-fold with a 10-fold increase in the (-)-B[c]PhDE-2-dA(t) adduct. Treatment of HepG2 cells with TCDD prior to B[c]Ph application did not increase B[c]PhDE-DNA binding. Total B[c]PhDE-DNA adducts increased 3-fold in TCDD-treated mouse epidermis: the majority of the increase resulted from (+)- B[c]PhDE-1-dA adducts. Analysis of P450 enzymes by Western blotting detected a large increase of P4501B1 but almost no increase in P4501A1 in MCF-7 cells exposed to 10 μM B[c]Ph for 24 or 48 h. In HepG2 cells, there were no detectable levels of P4501A1 or P4501B1 after treatment with 10 μM B[c]Ph for 24 h. In contrast, topical application of 2 μmol of B[c]Ph to mouse skin for 48 or 72 h increased P4501A1, but no P4501B1 was detected. As a measure of P450 activity, the metabolism of 7,12-dimethylbenz[a]anthracene (DMBA) was analyzed in microsomes prepared from MCF-7 and HepG2 cells exposed to 0.1% DMSO, 10 μM B[c]Ph, or 10 nM TCDD for 24 or 48 h and from mouse epidermis treated with 1 μg of TCDD, or vehicle control for 72 h, or 2μmol of B[c]Ph for 48 h. The levels of DMBA metabolites were low or undetectable in microsomes from B[c]Ph-treated MCF-7 and HepG2 cells, but a metabolite pattern consistent with P4501A1 metabolism of DMBA was present in B[c]Ph- exposed mouse epidermal microsomes. TCDD-treated MCF-7 cells, HepG2 cells, and mouse epidermis had DMBA metabolism patterns characteristic of P4501A1 activity. Microsomes from TCDD-treated human cells formed a higher proportion of the proximate carcinogenic metabolite DMBA-3,4-dihydrodiol (16% of total identified metabolites) than TCDD-treated mouse epidermis (2%). In mouse epidermis, the weak ability of B[c]Ph to increase hydrocarbon-metabolizing activity and the increase in mainly P4501A1, leading to formation of the less carcinogenic stereoisomer B[c]PhDE-1, may explain the low carcinogenic activity of B[c]Ph. In a human mammary carcinoma cell line, treatment with B[c]Ph increases mainly P4501B1 and results in formation of a higher proportion of the more carcinogenic B[c]PhDE-2. This indicates that cells in which B[c]Ph treatment increases P4501B1 levels effectively activate B[c]Ph to potent carcinogenic metabolites.

Original languageEnglish (US)
Pages (from-to)609-617
Number of pages9
JournalChemical Research in Toxicology
Volume10
Issue number5
DOIs
StatePublished - May 1 1997

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Enzyme Induction
Epidermis
Cytochrome P-450 Enzyme System
Chemical activation
Cells
Cell Line
Epoxy Compounds
MCF-7 Cells
Hep G2 Cells
9,10-Dimethyl-1,2-benzanthracene
Metabolites
Microsomes
Metabolism
Metabolic Activation
benzo(c)phenanthrene
DNA Adducts
Skin
1,4-dioxin
Polychlorinated Dibenzodioxins
Aryl Hydrocarbon Receptors

All Science Journal Classification (ASJC) codes

  • Toxicology

Cite this

Einolf, H. J., Story, W. T., Marcus, C. B., Larsen, M. C., Jefcoate, C. R., Greenlee, W. F., ... Baird, W. M. (1997). Role of cytochrome P450 enzyme induction in the metabolic activation of benzo[c]phenanthrene in human cell lines and mouse epidermis. Chemical Research in Toxicology, 10(5), 609-617. https://doi.org/10.1021/tx960174n
Einolf, Heidi J. ; Story, William T. ; Marcus, Craig B. ; Larsen, Michele C. ; Jefcoate, Colin R. ; Greenlee, William F. ; Yagi, Haruhiko ; Jerina, Donald M. ; Amin, Shantu ; Park, Sang S. ; Gelboin, Harry V. ; Baird, William M. / Role of cytochrome P450 enzyme induction in the metabolic activation of benzo[c]phenanthrene in human cell lines and mouse epidermis. In: Chemical Research in Toxicology. 1997 ; Vol. 10, No. 5. pp. 609-617.
@article{37463ffb41fa4bfe8971fffee75e517a,
title = "Role of cytochrome P450 enzyme induction in the metabolic activation of benzo[c]phenanthrene in human cell lines and mouse epidermis",
abstract = "The environmental contaminant benzo[c]phenanthrene (B[c]Ph) has weak carcinogenic activity in rodent bioassays; however, the fjord region diol epoxides of B[c]Ph, B[c]Ph-3,4-diol 1,2-epoxides (B[c]PhDE), are potent carcinogens. To determine the role of cytochrome P450 isozymes in the activation of B[c]Ph in MCF-7 cells and the low activation of B[c]Ph in mouse skin, cells of the MCF-7 and the human hepatoma HepG2 cell lines were treated with the potent Ah receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) prior to exposure to B[c]Ph for 24 h. Mice were treated topically with 1/μg of TCDD or vehicle (control) for 73 h and then with 2/μmol of B[c]Ph for 24 h. In MCF-7 cells, TCDD exposure increased B[c]PhDE-DNA adduct levels more than 3-fold with a 10-fold increase in the (-)-B[c]PhDE-2-dA(t) adduct. Treatment of HepG2 cells with TCDD prior to B[c]Ph application did not increase B[c]PhDE-DNA binding. Total B[c]PhDE-DNA adducts increased 3-fold in TCDD-treated mouse epidermis: the majority of the increase resulted from (+)- B[c]PhDE-1-dA adducts. Analysis of P450 enzymes by Western blotting detected a large increase of P4501B1 but almost no increase in P4501A1 in MCF-7 cells exposed to 10 μM B[c]Ph for 24 or 48 h. In HepG2 cells, there were no detectable levels of P4501A1 or P4501B1 after treatment with 10 μM B[c]Ph for 24 h. In contrast, topical application of 2 μmol of B[c]Ph to mouse skin for 48 or 72 h increased P4501A1, but no P4501B1 was detected. As a measure of P450 activity, the metabolism of 7,12-dimethylbenz[a]anthracene (DMBA) was analyzed in microsomes prepared from MCF-7 and HepG2 cells exposed to 0.1{\%} DMSO, 10 μM B[c]Ph, or 10 nM TCDD for 24 or 48 h and from mouse epidermis treated with 1 μg of TCDD, or vehicle control for 72 h, or 2μmol of B[c]Ph for 48 h. The levels of DMBA metabolites were low or undetectable in microsomes from B[c]Ph-treated MCF-7 and HepG2 cells, but a metabolite pattern consistent with P4501A1 metabolism of DMBA was present in B[c]Ph- exposed mouse epidermal microsomes. TCDD-treated MCF-7 cells, HepG2 cells, and mouse epidermis had DMBA metabolism patterns characteristic of P4501A1 activity. Microsomes from TCDD-treated human cells formed a higher proportion of the proximate carcinogenic metabolite DMBA-3,4-dihydrodiol (16{\%} of total identified metabolites) than TCDD-treated mouse epidermis (2{\%}). In mouse epidermis, the weak ability of B[c]Ph to increase hydrocarbon-metabolizing activity and the increase in mainly P4501A1, leading to formation of the less carcinogenic stereoisomer B[c]PhDE-1, may explain the low carcinogenic activity of B[c]Ph. In a human mammary carcinoma cell line, treatment with B[c]Ph increases mainly P4501B1 and results in formation of a higher proportion of the more carcinogenic B[c]PhDE-2. This indicates that cells in which B[c]Ph treatment increases P4501B1 levels effectively activate B[c]Ph to potent carcinogenic metabolites.",
author = "Einolf, {Heidi J.} and Story, {William T.} and Marcus, {Craig B.} and Larsen, {Michele C.} and Jefcoate, {Colin R.} and Greenlee, {William F.} and Haruhiko Yagi and Jerina, {Donald M.} and Shantu Amin and Park, {Sang S.} and Gelboin, {Harry V.} and Baird, {William M.}",
year = "1997",
month = "5",
day = "1",
doi = "10.1021/tx960174n",
language = "English (US)",
volume = "10",
pages = "609--617",
journal = "Chemical Research in Toxicology",
issn = "0893-228X",
publisher = "American Chemical Society",
number = "5",

}

Einolf, HJ, Story, WT, Marcus, CB, Larsen, MC, Jefcoate, CR, Greenlee, WF, Yagi, H, Jerina, DM, Amin, S, Park, SS, Gelboin, HV & Baird, WM 1997, 'Role of cytochrome P450 enzyme induction in the metabolic activation of benzo[c]phenanthrene in human cell lines and mouse epidermis', Chemical Research in Toxicology, vol. 10, no. 5, pp. 609-617. https://doi.org/10.1021/tx960174n

Role of cytochrome P450 enzyme induction in the metabolic activation of benzo[c]phenanthrene in human cell lines and mouse epidermis. / Einolf, Heidi J.; Story, William T.; Marcus, Craig B.; Larsen, Michele C.; Jefcoate, Colin R.; Greenlee, William F.; Yagi, Haruhiko; Jerina, Donald M.; Amin, Shantu; Park, Sang S.; Gelboin, Harry V.; Baird, William M.

In: Chemical Research in Toxicology, Vol. 10, No. 5, 01.05.1997, p. 609-617.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Role of cytochrome P450 enzyme induction in the metabolic activation of benzo[c]phenanthrene in human cell lines and mouse epidermis

AU - Einolf, Heidi J.

AU - Story, William T.

AU - Marcus, Craig B.

AU - Larsen, Michele C.

AU - Jefcoate, Colin R.

AU - Greenlee, William F.

AU - Yagi, Haruhiko

AU - Jerina, Donald M.

AU - Amin, Shantu

AU - Park, Sang S.

AU - Gelboin, Harry V.

AU - Baird, William M.

PY - 1997/5/1

Y1 - 1997/5/1

N2 - The environmental contaminant benzo[c]phenanthrene (B[c]Ph) has weak carcinogenic activity in rodent bioassays; however, the fjord region diol epoxides of B[c]Ph, B[c]Ph-3,4-diol 1,2-epoxides (B[c]PhDE), are potent carcinogens. To determine the role of cytochrome P450 isozymes in the activation of B[c]Ph in MCF-7 cells and the low activation of B[c]Ph in mouse skin, cells of the MCF-7 and the human hepatoma HepG2 cell lines were treated with the potent Ah receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) prior to exposure to B[c]Ph for 24 h. Mice were treated topically with 1/μg of TCDD or vehicle (control) for 73 h and then with 2/μmol of B[c]Ph for 24 h. In MCF-7 cells, TCDD exposure increased B[c]PhDE-DNA adduct levels more than 3-fold with a 10-fold increase in the (-)-B[c]PhDE-2-dA(t) adduct. Treatment of HepG2 cells with TCDD prior to B[c]Ph application did not increase B[c]PhDE-DNA binding. Total B[c]PhDE-DNA adducts increased 3-fold in TCDD-treated mouse epidermis: the majority of the increase resulted from (+)- B[c]PhDE-1-dA adducts. Analysis of P450 enzymes by Western blotting detected a large increase of P4501B1 but almost no increase in P4501A1 in MCF-7 cells exposed to 10 μM B[c]Ph for 24 or 48 h. In HepG2 cells, there were no detectable levels of P4501A1 or P4501B1 after treatment with 10 μM B[c]Ph for 24 h. In contrast, topical application of 2 μmol of B[c]Ph to mouse skin for 48 or 72 h increased P4501A1, but no P4501B1 was detected. As a measure of P450 activity, the metabolism of 7,12-dimethylbenz[a]anthracene (DMBA) was analyzed in microsomes prepared from MCF-7 and HepG2 cells exposed to 0.1% DMSO, 10 μM B[c]Ph, or 10 nM TCDD for 24 or 48 h and from mouse epidermis treated with 1 μg of TCDD, or vehicle control for 72 h, or 2μmol of B[c]Ph for 48 h. The levels of DMBA metabolites were low or undetectable in microsomes from B[c]Ph-treated MCF-7 and HepG2 cells, but a metabolite pattern consistent with P4501A1 metabolism of DMBA was present in B[c]Ph- exposed mouse epidermal microsomes. TCDD-treated MCF-7 cells, HepG2 cells, and mouse epidermis had DMBA metabolism patterns characteristic of P4501A1 activity. Microsomes from TCDD-treated human cells formed a higher proportion of the proximate carcinogenic metabolite DMBA-3,4-dihydrodiol (16% of total identified metabolites) than TCDD-treated mouse epidermis (2%). In mouse epidermis, the weak ability of B[c]Ph to increase hydrocarbon-metabolizing activity and the increase in mainly P4501A1, leading to formation of the less carcinogenic stereoisomer B[c]PhDE-1, may explain the low carcinogenic activity of B[c]Ph. In a human mammary carcinoma cell line, treatment with B[c]Ph increases mainly P4501B1 and results in formation of a higher proportion of the more carcinogenic B[c]PhDE-2. This indicates that cells in which B[c]Ph treatment increases P4501B1 levels effectively activate B[c]Ph to potent carcinogenic metabolites.

AB - The environmental contaminant benzo[c]phenanthrene (B[c]Ph) has weak carcinogenic activity in rodent bioassays; however, the fjord region diol epoxides of B[c]Ph, B[c]Ph-3,4-diol 1,2-epoxides (B[c]PhDE), are potent carcinogens. To determine the role of cytochrome P450 isozymes in the activation of B[c]Ph in MCF-7 cells and the low activation of B[c]Ph in mouse skin, cells of the MCF-7 and the human hepatoma HepG2 cell lines were treated with the potent Ah receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) prior to exposure to B[c]Ph for 24 h. Mice were treated topically with 1/μg of TCDD or vehicle (control) for 73 h and then with 2/μmol of B[c]Ph for 24 h. In MCF-7 cells, TCDD exposure increased B[c]PhDE-DNA adduct levels more than 3-fold with a 10-fold increase in the (-)-B[c]PhDE-2-dA(t) adduct. Treatment of HepG2 cells with TCDD prior to B[c]Ph application did not increase B[c]PhDE-DNA binding. Total B[c]PhDE-DNA adducts increased 3-fold in TCDD-treated mouse epidermis: the majority of the increase resulted from (+)- B[c]PhDE-1-dA adducts. Analysis of P450 enzymes by Western blotting detected a large increase of P4501B1 but almost no increase in P4501A1 in MCF-7 cells exposed to 10 μM B[c]Ph for 24 or 48 h. In HepG2 cells, there were no detectable levels of P4501A1 or P4501B1 after treatment with 10 μM B[c]Ph for 24 h. In contrast, topical application of 2 μmol of B[c]Ph to mouse skin for 48 or 72 h increased P4501A1, but no P4501B1 was detected. As a measure of P450 activity, the metabolism of 7,12-dimethylbenz[a]anthracene (DMBA) was analyzed in microsomes prepared from MCF-7 and HepG2 cells exposed to 0.1% DMSO, 10 μM B[c]Ph, or 10 nM TCDD for 24 or 48 h and from mouse epidermis treated with 1 μg of TCDD, or vehicle control for 72 h, or 2μmol of B[c]Ph for 48 h. The levels of DMBA metabolites were low or undetectable in microsomes from B[c]Ph-treated MCF-7 and HepG2 cells, but a metabolite pattern consistent with P4501A1 metabolism of DMBA was present in B[c]Ph- exposed mouse epidermal microsomes. TCDD-treated MCF-7 cells, HepG2 cells, and mouse epidermis had DMBA metabolism patterns characteristic of P4501A1 activity. Microsomes from TCDD-treated human cells formed a higher proportion of the proximate carcinogenic metabolite DMBA-3,4-dihydrodiol (16% of total identified metabolites) than TCDD-treated mouse epidermis (2%). In mouse epidermis, the weak ability of B[c]Ph to increase hydrocarbon-metabolizing activity and the increase in mainly P4501A1, leading to formation of the less carcinogenic stereoisomer B[c]PhDE-1, may explain the low carcinogenic activity of B[c]Ph. In a human mammary carcinoma cell line, treatment with B[c]Ph increases mainly P4501B1 and results in formation of a higher proportion of the more carcinogenic B[c]PhDE-2. This indicates that cells in which B[c]Ph treatment increases P4501B1 levels effectively activate B[c]Ph to potent carcinogenic metabolites.

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