Picropodophyllin induces downregulation of the insulin-like growth factor 1 receptor: potential mechanistic involvement of Mdm2 and beta-arrestin1.
Oncogene
; 27(11): 1629-38, 2008 Mar 06.
Article
em En
| MEDLINE
| ID: mdl-17828296
ABSTRACT
The insulin-like growth factor 1 receptor (IGF-1R) is crucial for growth and survival of malignant cells. Experience in targeting IGF-1R in cancer models has shown that strategies promoting downregulation of the receptor are much more efficient in inducing apoptosis than those inhibiting the IGF-1R activity. Recently, we found that the cyclolignan picropodophyllin (PPP) inhibits phosphorylation of IGF-1R and activation of downstream signaling without interfering with the highly homologous insulin receptor (IR). Furthermore, PPP treatment caused strong regression of tumor grafts and prolonged survival of animals with systemic tumor disease. Here we demonstrate that PPP also downregulates the IGF-1R, whereas the IR and several other receptors were not affected. PPP-induced IGF-1R downregulation required expression of the MDM2 E3 ligase, which recently was found to ubiquitinate and cause degradation of the IGF-1R. In addition knockdown of beta-arrestin1, the adaptor molecule known to bridges MDM2 and IGF-1R, prevented downregulation of the receptor and significantly decreased PPP-induced cell death. All together these data suggest that PPP downregulates IGF-1R by interfering with the action of beta-arrestin1/MDM2 as well as the achieved receptor downregulation contributes to the apoptotic effect of PPP.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Podofilotoxina
/
Regulação para Baixo
/
Receptor IGF Tipo 1
/
Arrestinas
/
Proteínas Proto-Oncogênicas c-mdm2
/
Neoplasias
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Oncogene
Ano de publicação:
2008
Tipo de documento:
Article