Necrosis in DU145 prostate cancer spheroids induces COX-2/mPGES-1-derived PGE2 to promote tumor growth and to inhibit T cell activation.
Int J Cancer
; 133(7): 1578-88, 2013 Oct 01.
Article
en En
| MEDLINE
| ID: mdl-23536473
Cyclooxygenase (COX)-2-derived prostaglandin E2 (PGE2 ) supports the growth of a spectrum of cancers. The potential benefit of COX-2-inhibiting non-steroidal anti-inflammatory drugs (NSAIDs) for cancer treatment is however limited by their well-known cardiovascular side-effects. Therefore, targeting microsomal PGE synthase 1 (mPGES-1), the downstream enzyme in the COX-2-dependent pathway of PGE2 production might be attractive, although conflicting data regarding a potential tumor-supporting function of mPGES-1 were reported. We determined the impact of mPGES-1 in human DU145 prostate cancer cell growth. Surprisingly, knockdown of mPGES-1 did not alter growth of DU145 monolayer cells, but efficiently inhibited the growth of DU145 multicellular tumor spheroids (MCTS). Opposed to MCTS, monolayer cells did not secrete PGE2 due to a lack of COX-2 expression, which was induced during spheroid formation. Pharmacological inhibition of COX-2 and mPGES-1 supported the crucial role of PGE2 for growth of MCTS. The functionality of spheroid-derived PGE2 was demonstrated by its ability to inhibit cytotoxic T cell activation. When investigating mechanisms of spheroid-induced COX-2 induction, we observed that among microenvironmental factors neither glucose deprivation, hypoxia nor tumor cell apoptosis enhanced COX-2 expression. Interestingly, interfering with apoptosis in spheroids triggered a shift towards necrosis, thus augmenting COX-2 expression. We went on to demonstrate that necrotic cells induced COX-2 mRNA expression and PGE2 secretion from live tumor cells. In conclusion, necrosis-dependent COX-2 upregulation in MCTS promoted PGE2 -dependent tumor growth and inhibited activated cytotoxic T cells. Hence, blocking mPGES-1 as a therapeutic option may be considered for COX-2/mPGES-1-positive solid cancers.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Neoplasias de la Próstata
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Dinoprostona
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Esferoides Celulares
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Oxidorreductasas Intramoleculares
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Ciclooxigenasa 2
Límite:
Humans
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Male
Idioma:
En
Revista:
Int J Cancer
Año:
2013
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Estados Unidos