title: N-Nitrosopiperidine and N-Nitrosodibutylamine induce apoptosis in HepG2 cells via the caspase dependent pathway.
abstract: The human hepatoma cell line (HepG2) exhibited a dose and time-dependent apoptotic response following treatment with N-Nitrosopiperidine (NPIP) and N-Nitrosodibutylamine (NDBA), two recognized human carcinogens. Our results showed a significant apoptotic cell death (95%) after 24h treatment with NDBA (3.5 mM), whereas it was necessary to use high doses of NPIP (45 mM) to obtain a similar percentage of apoptotic cells (86%). In addition, both extrinsic (caspase-8) and intrinsic pathway (caspase-9) could be implicated in the N-Nitrosamines-induced apoptosis. This study also addresses the role of reactive oxygen species (ROS) as intermediates for apoptosis signaling. A significant increase in ROS levels was observed after NPIP treatment, whereas NDBA did not induce ROS. However, N-acetylcysteine (NAC) did not block NPIP-induced apoptosis. All these findings suggest that NPIP and NDBA induce apoptosis in HepG2 cells via a pathway that involves caspases but not ROS.
authors.affiliation: Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: García
authors.forename: Paloma
authors.initials: P
authors.lastname: Morales
authors.forename: Joseph
authors.initials: J
authors.lastname: Rafter
authors.forename: Ana I
authors.initials: AI
authors.lastname: Haza
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002273:Carcinogens / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D004052:Diethylnitrosamine / Q000494:pharmacology*; D056945:Hep G2 Cells; D006801:Humans; D020287:In Situ Nick-End Labeling; D008113:Liver Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D009602:Nitrosamines / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D000477:Alkylating Agents; D002273:Carcinogens; D009602:Nitrosamines; D017382:Reactive Oxygen Species; D004052:Diethylnitrosamine; C002743:N-nitrosopiperidine; D020169:Caspases