title: p53/T-antigen complex disruption in T-antigen transformed NIH3T3 fibroblasts exposed to oxidative stress: correlation with the appearance of a Fas/APO-1/CD95 dependent, caspase independent, necrotic pathway.
abstract: Simian Virus 40 Large T-antigen expressed in NIH3T3 cells increases p53 level and interacts with this tumor suppressor to form large nuclear complexes. We show here that T-antigen sensitizes NIH3T3 cells to low doses of the oxidative stress inducer menadione. This oxidant increased p53 accumulation and disrupted p53/T-antigen interaction, but not T-antigen/pRb, T-antigen/Hsc70 and p53/Hsc70 complexes; a phenomenon inhibited by the anti-oxidant N-acetyl-cysteine. Analysis of several p53 downstream gene products revealed that the level of Fas receptor, which was sharply reduced by T-antigen expression, was drastically increased in response to menadione treatment. Menadione also induced a T-antigen dependent cleavage of Fas ligand. Analysis performed with Fas receptor antagonist antibody and metalloproteinases inhibitor revealed that menadione triggers a Fas-dependent death of a fraction of T-antigen expressing cells. This Fas pathway does not activate caspase 8 or 3, probably because of the inhibition induced by T-antigen, and leads to a necrotic cell death which contributes at least in part to the hypersensitivity of T-antigen transformed cells to oxidative stress.
authors.affiliation: Centre de Génétique Moléculaire et Cellulaire, CNRS-UMR-5534, Université Claude Bernard LYON1, Villeurbanne, France.
authors.forename: S
authors.initials: S
authors.lastname: Gonin
authors.forename: C
authors.initials: C
authors.lastname: Diaz-Latoud
authors.forename: M J
authors.initials: MJ
authors.lastname: Richard
authors.forename: M V
authors.initials: MV
authors.lastname: Ursini
authors.forename: A
authors.initials: A
authors.lastname: Imbo
authors.forename: F
authors.initials: F
authors.lastname: Manero
authors.forename: A P
authors.initials: AP
authors.lastname: Arrigo
mesh_terms: D016475:3T3 Cells; D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics* / Q000378:metabolism*; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects; D002471:Cell Transformation, Neoplastic; D051379:Mice; D009336:Necrosis; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013539:Simian virus 40 / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D014812:Vitamin K / Q000494:pharmacology; D019014:fas Receptor / Q000187:drug effects / Q000502:physiology*
chemical_list: D000906:Antibodies; D000952:Antigens, Polyomavirus Transforming; D000975:Antioxidants; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D019014:fas Receptor; D014812:Vitamin K; D000111:Acetylcysteine