title: 3-Nitrofluoranthene (3-NF) but not 3-aminofluoranthene (3-AF) elicits apoptosis as well as programmed necrosis in Hepa1c1c7 cells.
abstract: In this study, we show that the environmental pollutant, 3-nitrofluoranthene (3-NF) but not its amine form, 3-aminofluoranthene (3-AF), induces apoptosis as well as regulated necrosis with necroptotic features in Hepa1c1c7 cells. Upon exposure to 3-NF, both typical apoptotic and necrotic cells were observed. A large number of the cells exhibited a characteristic partial nuclear chromatin condensation. Cycloheximide completely attenuated 3-NF-induced cell death. Activation of caspase-8, -9, and -3 were observed. Moreover, Z-VAD-FMK decreased the apoptotic cells, whereas the number of propidium iodide (PI)-positive cells with partial chromatin condensation was reduced by Nec-1, an inhibitor of receptor interacting protein (RIP-1). Cyp1a1, but not nitric oxide synthase (NOS), appears to be involved in activation of 3-NF to reactive metabolites. Increase in the number as well as size of lysosomes, myelinosomes, and activation of autophagy were also observed. 3-NF induced phosphorylation of ERK1/2, JNK and p38 MAPKs. Interestingly, while inhibitors of ERK1/2 and JNK reduced apoptotic as well as necrotic cell death, the p38 inhibitor, SB202190 reduced only the necrotic cell death. Taken together, 3-NF elicits both apoptosis and a caspase-independent programmed cell death (PCD) with autophagic characteristics. Conversely, with 3-AF, no apparent cytotoxic effects besides a reduction in cell proliferation was observed.
authors.affiliation: Division of Environmental Medicine, Norwegian Institute of Public Health, P.O. Box 4404 Nydalen, N-0403 Oslo, Norway. nana.asare@fhi.no
authors.forename: Nana
authors.initials: N
authors.lastname: Asare
authors.forename: Marit
authors.initials: M
authors.lastname: Låg
authors.forename: Dominique
authors.initials: D
authors.lastname: Lagadic-Gossmann
authors.forename: Mary
authors.initials: M
authors.lastname: Rissel
authors.forename: Per
authors.initials: P
authors.lastname: Schwarze
authors.forename: Jørn A
authors.initials: JA
authors.lastname: Holme
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D005449:Fluorenes / Q000633:toxicity*; D051379:Mice; D046529:Microscopy, Electron, Transmission; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009336:Necrosis
chemical_list: D005449:Fluorenes; C046693:3-aminofluoranthene; D020928:Mitogen-Activated Protein Kinases; C033643:3-nitrofluoranthene