title: TNF-alpha activates at least two apoptotic signaling cascades.
abstract: Apoptosis, the process whereby cells activate an intrinsic death program, can be induced in HeLa cells by TNF-alpha treatment. The aims of the present study were (i) to examine the precise role and the origin of Reactive Oxygen Species (ROS) in the TNF-alpha-induced programmed cell death, (ii) to characterize and order the morphological and mitochondrial changes associated with this process and (iii) to link these events with the activation of caspases. Analyses were performed on TNF-alpha-treated cells in the presence of an anti-oxidant, or of a general caspase inhibitor. To assess the role of mitochondria in the cell death signal transduction, these studies were also realized on HeLa-variant cell lines lacking functional mitochondrial respiratory chain. We show that at least two separate signaling cascades, both mediated by Z-VAD-sensitive caspase(s), contribute to the TNF-alpha-induced apoptosis of HeLa cells. One signaling pathway involves an early mitochondria-dependent ROS production, the other being ROS-independent.
authors.affiliation: Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.
authors.forename: C
authors.initials: C
authors.lastname: Sidoti-de Fraisse
authors.forename: V
authors.initials: V
authors.lastname: Rincheval
authors.forename: Y
authors.initials: Y
authors.lastname: Risler
authors.forename: B
authors.initials: B
authors.lastname: Mignotte
authors.forename: J L
authors.initials: JL
authors.lastname: Vayssière
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism* / Q000494:pharmacology; D020741:rho GTP-Binding Proteins
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D015853:Cysteine Proteinase Inhibitors; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D019204:GTP-Binding Proteins; D020741:rho GTP-Binding Proteins