IFN-alpha enhances TNF-alpha-induced apoptosis through down-regulation of c-Myc protein expression in HL-60 cells.
J Exp Clin Cancer Res
; 24(3): 447-56, 2005 Sep.
Article
en En
| MEDLINE
| ID: mdl-16270532
We examined the effect of interferon-alpha (IFN-alpha) in combination with tumor necrosis factor-a (TNF-alpha) on growth, differentiation and apoptosis in HL-60 human myeloid leukemia cells. IFN-alpha inhibited cell growth and induced apoptosis, but not differentiation, in HL-60 cells. IFN-alpha enhanced TNF-alpha-induced apoptosis. We also investigated the expression of c-Myc and Bcl-2 oncoproteins, which are implicated in the survival or death of a cell. The levels of c-Myc protein expression were not changed by IFN-alpha alone at 24hrs of treatment, but were down-regulated at 72 hrs, accompanied by the appearance of apoptotic cells. While, IFN-alpha did not affect the level of Bcl-2 protein expression during this cultivation time. Interestingly, a combination treatment of IFN-alpha with TNF-alpha showed a greater decrease of c-Myc expression than TNF-a alone at 24hrs. Whereas, IFN-alpha did not significantly modulate Bcl-2 expression levels which were down-regulated by TNF-alpha. Therefore, the enhancement of TNF-alpha-induced apoptosis by IFN-a might be closely associated with the greater down-regulation of c-Myc protein, rather than Bcl-2. In contrast, with rapid down-regulation of c-Myc expression caused by TNF-alpha, IFN-alpha down-regulated c-Myc rather late (at 72 hrs), suggesting that both cytokines have a distinct pathway regulating c-Myc protein expression. However, the enhancement of apoptosis in the combination treatment would suggest the presence of a common signaling pathway for induction of apoptosis at down-stream of c-Myc.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Regulación hacia Abajo
/
Proteínas Proto-Oncogénicas c-myc
/
Factor de Necrosis Tumoral alfa
/
Interferón-alfa
/
Apoptosis
Límite:
Humans
Idioma:
En
Revista:
J Exp Clin Cancer Res
Año:
2005
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Reino Unido