3-Nitrobenzanthrone and 3-aminobenzanthrone induce DNA damage and cell signalling in Hepa1c1c7 cells.
3-Nitrobenzanthrone (3-NBA) is a mutagenic and carcinogenic environmental pollutant found in diesel exhaust and urban air pollution. In the present work we have characterised the effects of 3-NBA and its metabolite 3-aminobenzanthrone (3-ABA) on cell death and cytokine release in mouse hepatoma Hepa1c1c7 cells. These effects were related to induced DNA damage and changes in cell signalling pathways. 3-NBA resulted in cell death and caused most DNA damage as judged by the amount of DNA adducts ((32)P-postlabelling assay), single strand (ss)DNA breaks and oxidative DNA lesions (comet assay) detected. An increased phosphorylation of H2AX, chk1, chk2 and partly ATM was observed using flow cytometry and/or Western blotting. Both compounds increased phosphorylation of p53 and MAPKs (ERK, p38 and JNK). However, only 3-NBA caused an accumulation of p53 in the nucleus and a translocation of Bax to the mitochondria. The p53 inhibitor pifithrin-alpha inhibited 3-NBA-induced apoptosis, indicating that cell death was a result of the triggering of DNA signalling pathways. The highest phosphorylation of Akt and degradation of IkappaB-alpha (suggesting activation of NF-kappaB) were also seen after treatment with 3-NBA. In contrast 3-ABA increased IL-6 release, but caused little or no toxicity. Cytokine release was inhibited by PD98059 and curcumin, suggesting that ERK and NF-kappaB play a role in this process. In conclusion, 3-NBA seems to have a higher potency to induce DNA damage compatible with its cytotoxic effects, while 3-ABA seems to have a greater effect on the immune system.
Landvik
N E
NE
Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 404 Torshov N-4303 Oslo, Norway.
Arlt
V M
VM
Nagy
E
E
Solhaug
A
A
Tekpli
X
X
Schmeiser
H H
HH
Refsnes
M
M
Phillips
D H
DH
Lagadic-Gossmann
D
D
Holme
J A
JA
D000818:Animals; D001551:Benz(a)Anthracenes / Q000008:administration & dosage / Q000633:toxicity*; D002453:Cell Cycle / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D054426:Chemokine CXCL2 / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects*; D004785:Environmental Pollutants / Q000633:toxicity*; D015850:Interleukin-6 / Q000378:metabolism; D008114:Liver Neoplasms, Experimental / Q000235:genetics*; D051379:Mice; D009153:Mutagens / Q000633:toxicity*; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*
C475568:3-aminobenzanthrone; D001551:Benz(a)Anthracenes; D054426:Chemokine CXCL2; D004785:Environmental Pollutants; D015850:Interleukin-6; D009153:Mutagens; D018336:Receptors, Aryl Hydrocarbon; C117220:3-nitrobenzanthrone