Medulloblastomas overexpress the p53-inactivating oncogene WIP1/PPM1D.
J Neurooncol
; 86(3): 245-56, 2008 Feb.
Article
en En
| MEDLINE
| ID: mdl-17932621
ABSTRACT
Medulloblastoma is the most common malignant brain tumor of childhood. Despite numerous advances, clinical challenges range from recurrent and progressive disease to long-term toxicities in survivors. The lack of more effective, less toxic therapies results from our limited understanding of medulloblastoma growth. Although TP53 is the most commonly altered gene in cancers, it is rarely mutated in medulloblastoma. Accumulating evidence, however, indicates that TP53 pathways are disrupted in medulloblastoma. Wild-type p53-induced phosphatase 1 (WIP1 or PPM1D) encodes a negative regulator of p53. WIP1 amplification (17q22-q23) and its overexpression have been reported in diverse cancer types. We examined primary medulloblastoma specimens and cell lines, and detected WIP1 copy gain and amplification prevalent among but not exclusively in the tumors with 17q gain and isochromosome 17q (i17q), which are among the most common cytogenetic lesions in medulloblastoma. WIP1 RNA levels were significantly higher in the tumors with 17q gain or i17q. Immunoblots confirmed significant WIP1 protein in primary tumors, generally higher in those with 17q gain or i17q. Under basal growth conditions and in response to the chemotherapeutic agent, etoposide, WIP1 antagonized p53-mediated apoptosis in medulloblastoma cell lines. These results indicate that medulloblastoma express significant levels of WIP1 that modulate genotoxic responsiveness by negatively regulating p53.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Regulación Neoplásica de la Expresión Génica
/
Fosfoproteínas Fosfatasas
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Meduloblastoma
Tipo de estudio:
Observational_studies
Límite:
Adolescent
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Child
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Child, preschool
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Female
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Humans
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Infant
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Male
Idioma:
En
Revista:
J Neurooncol
Año:
2008
Tipo del documento:
Article
País de afiliación:
Estados Unidos