E1A oncogene enhancement of caspase-2-mediated mitochondrial injury sensitizes cells to macrophage nitric oxide-induced apoptosis.
J Immunol
; 180(12): 8272-9, 2008 Jun 15.
Article
em En
| MEDLINE
| ID: mdl-18523293
ABSTRACT
The adenovirus E1A oncogene induces innate immune rejection of tumors by sensitizing tumor cells to apoptosis in response to injuries, such as those inflicted by macrophage-produced TNF alpha and NO. E1A sensitizes cells to TNF by repressing its activation of NF-kappaB-dependent, antiapoptotic defenses. This suggested the hypothesis that E1A blockade of the NF-kappaB activation response might be the central mechanism of E1A induced cellular sensitivity to other proapoptotic injuries, such as macrophage-produced NO. However, creation of E1A-positive NIH-3T3 mouse cell variants with high-level, NF-kappaB-dependent resistance to TNF did not coselect for resistance to apoptosis induced by either macrophage-NO or chemical-NO, as the hypothesis would predict. E1A expression did block cellular recovery from NO-induced mitochondrial injury and converted the reversible, NO-induced cytostasis response of cells to an apoptotic response. This viral oncogene-induced phenotypic conversion of the cellular injury response of mouse and human cells was mediated by an E1A-related increase in NO-induced activation of caspase-2, an apical initiator of intrinsic apoptosis. Blocking caspase-2 activation or expression eliminated the NO-induced apoptotic response of E1A-positive cells. These results define an NF-kappaB-independent pathway through which the E1A gene of human adenovirus sensitizes mouse and human cells to apoptosis by enhancement of caspase-2-mediated mitochondrial injury.
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Base de dados:
MEDLINE
Assunto principal:
Apoptose
/
Proteínas E1A de Adenovirus
/
Caspase 2
/
Macrófagos
/
Mitocôndrias
/
Óxido Nítrico
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article