Granzyme B triggers a prolonged pressure to die in Bcl-2 overexpressing cells, defining a window of opportunity for effective treatment with ABT-737.
Cell Death Dis
; 3: e344, 2012 Jul 05.
Article
en En
| MEDLINE
| ID: mdl-22764103
Overexpression of Bcl-2 contributes to resistance of cancer cells to human cytotoxic lymphocytes (CL) by blocking granzyme B (GraB)-induced mitochondrial outer membrane permeabilization (MOMP). Drugs that neutralise Bcl-2 (e.g., ABT-737) may therefore be effective adjuvants for immunotherapeutic strategies that use CL to kill cancer cells. Consistent with this we found that ABT-737 effectively restored MOMP in Bcl-2 overexpressing cells treated with GraB or natural killer cells. This effect was observed even if ABT-737 was added up to 16 h after GraB, after which the cells reset their resistant phenotype. Sensitivity to ABT-737 required initial cleavage of Bid by GraB (gctBid) but did not require ongoing GraB activity once Bid had been cleaved. This gctBid remained detectable in cells that were sensitive to ABT-737, but Bax and Bak were only activated if ABT-737 was added to the cells. These studies demonstrate that GraB generates a prolonged pro-apoptotic signal that must remain active for ABT-737 to be effective. The duration of this signal is determined by the longevity of gctBid but not activation of Bax or Bak. This defines a therapeutic window in which ABT-737 and CL synergise to cause maximum death of cancer cells that are resistant to either treatment alone, which will be essential in defining optimum treatment regimens.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Sulfonamidas
/
Compuestos de Bifenilo
/
Apoptosis
/
Proteínas Proto-Oncogénicas c-bcl-2
/
Granzimas
/
Nitrofenoles
Límite:
Humans
Idioma:
En
Revista:
Cell Death Dis
Año:
2012
Tipo del documento:
Article
País de afiliación:
Australia
Pais de publicación:
Reino Unido