TY - JOUR
T1 - Effect of metals on polycyclic aromatic hydrocarbon induction of CYP1A1 and CYP1A2 in human hepatocyte cultures
AU - Vakharia, Dilip D.
AU - Liu, Ning
AU - Pause, Ronald
AU - Fasco, Michael
AU - Bessette, Erin
AU - Zhang, Qing Yu
AU - Kaminsky, Laurence S.
N1 - Funding Information:
The authors are grateful to Ms. Jill Panetta for preparation of the manuscript. Although the research described in this article has been funded in part by the United States Environmental Protection Agency through Grant R827180010 to Laurence S. Kaminsky, it has not been subjected to the Agency’s required peer and policy review and therefore does not necessarily reflect the views of the Agency and no official endorsement should be inferred. N. Liu, who is affiliated with the Division of Environmental Health, Department of Preventive Medicine, Jiangxi Medical College, Nanchang, China, is grateful to The World Health Organization for support. The Molecular Genetics Core of the Wads-worth Center is acknowledged for the preparation of oligonucleotide primers.
PY - 2001/1/15
Y1 - 2001/1/15
N2 - Environmental cocontamination by polycyclic aromatic hydrocarbons (PAHs) and metals could affect the carcinogenic consequences of PAH exposure by modifying PAH induction of PAH-bioactivating CYP1A. The effect of As, Pb, Hg, or Cd (ranked as the most hazardous environmental metals by EPA and ATSDR) on CYP1A1 and 1A2 induction by benzo[a]pyrene (BaP), benzo[b]fluoranthene (BbF), dibenzo[a,h]anthracene (DBahA), benzo[a]anthracene (BaA), and benzo[k]fluoranthene (BkF) has thus been investigated in fresh human hepatocyte cultures. Induction was probed by ethoxyresorufin-O-deethylase activity, by immunoblots, and by RT-PCR. Uptake of PAHs into the hepatocytes varied according to PAH and liver donor: 84% of 5 μM BaA and 25-40% of 5 μM DBahA was taken up in 24 h. Hepatocytes retained viability up to 1 μM Cd and 5 μM Pb, Hg, or As and 5 μM PAHs. PAH induction of CYP1A in hepatocytes was variable, some cultures expressed CYP1A1 and others CYP1A1 and 1A2, and to variable extents. Induction efficiency (relative to DMSO controls) at 2.5 μM PAH concentration was in the order BkF (7.6-fold) > DBahA (6.1 fold) > BaP (5.7 fold) > BbF (3.9-fold) > BaA (2.5-fold). All four metals (1-5 μM) decreased CYP1A1/1A2 induction by some of the PAHs with dose-, metal-, and PAH-dependency. Arsenic (5 μM) decreased induction by 47% for BaP, 68% for BaA, 45% for BbF, 79% for BkF, and 53% for DBahA. Induced CYP1A2 protein was much more extensively decreased than 1A1 protein, and CYP1A2 mRNA and, to variable extents, CYP1A1 mRNA were decreased by As. Thus the metals in PAH/ metal mixtures could diminish PAH carcinogenicity by decreasing induction of their bioactivation by CYP1A1/1A2.
AB - Environmental cocontamination by polycyclic aromatic hydrocarbons (PAHs) and metals could affect the carcinogenic consequences of PAH exposure by modifying PAH induction of PAH-bioactivating CYP1A. The effect of As, Pb, Hg, or Cd (ranked as the most hazardous environmental metals by EPA and ATSDR) on CYP1A1 and 1A2 induction by benzo[a]pyrene (BaP), benzo[b]fluoranthene (BbF), dibenzo[a,h]anthracene (DBahA), benzo[a]anthracene (BaA), and benzo[k]fluoranthene (BkF) has thus been investigated in fresh human hepatocyte cultures. Induction was probed by ethoxyresorufin-O-deethylase activity, by immunoblots, and by RT-PCR. Uptake of PAHs into the hepatocytes varied according to PAH and liver donor: 84% of 5 μM BaA and 25-40% of 5 μM DBahA was taken up in 24 h. Hepatocytes retained viability up to 1 μM Cd and 5 μM Pb, Hg, or As and 5 μM PAHs. PAH induction of CYP1A in hepatocytes was variable, some cultures expressed CYP1A1 and others CYP1A1 and 1A2, and to variable extents. Induction efficiency (relative to DMSO controls) at 2.5 μM PAH concentration was in the order BkF (7.6-fold) > DBahA (6.1 fold) > BaP (5.7 fold) > BbF (3.9-fold) > BaA (2.5-fold). All four metals (1-5 μM) decreased CYP1A1/1A2 induction by some of the PAHs with dose-, metal-, and PAH-dependency. Arsenic (5 μM) decreased induction by 47% for BaP, 68% for BaA, 45% for BbF, 79% for BkF, and 53% for DBahA. Induced CYP1A2 protein was much more extensively decreased than 1A1 protein, and CYP1A2 mRNA and, to variable extents, CYP1A1 mRNA were decreased by As. Thus the metals in PAH/ metal mixtures could diminish PAH carcinogenicity by decreasing induction of their bioactivation by CYP1A1/1A2.
KW - Arsenite
KW - Cadmium
KW - CYP1A1
KW - CYP1A2
KW - Human hepatocytes
KW - Induction
KW - Lead
KW - Mercury
KW - Mixtures
KW - Polycyclic aromatic hydrocarbons
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U2 - 10.1006/taap.2000.9087
DO - 10.1006/taap.2000.9087
M3 - Article
C2 - 11162773
AN - SCOPUS:0035862870
VL - 170
SP - 93
EP - 103
JO - Toxicology and Applied Pharmacology
JF - Toxicology and Applied Pharmacology
SN - 0041-008X
IS - 2
ER -