Disruption of the p53-Mdm2 complex by Nutlin-3 reveals different cancer cell phenotypes.
Ethn Dis
; 18(2 Suppl 2): S2-1-8, 2008.
Article
em En
| MEDLINE
| ID: mdl-18646312
ABSTRACT
INTRODUCTION:
Mdm2 inhibits p53 transactivation by forming a p53-Mdm2 complex on chromatin. Upon DNA damage-induced complex disruption, such latent p53 can be activated, but in cells overexpressing Mdm2 because of a homozygous single nucleotide polymorphism at position 309 (T --> G) of mdm2, the complex is highly stable and cannot be disrupted by DNA damage, rendering p53 inactive.METHODS:
To determine whether the p53 response phenotype is influenced differentially in cells with variable mdm2 genotypes, we compared responses to DNA damage and targeted p53-Mdm2 complex disruption by Nutlin-3 in the following wild-type p53 human cancer cell lines A875 and CCF-STTG-1 (G/G for mdm2 SNP309), SJSA-1 (mdm2 genomic amplification and T/T for mdm2 SNP309), MCF-7 (estrogen-induced Mdm2 overexpression and T/G for mdm2 SNP309), ML-1 and H460 (T/T for mdm2 SNP309), and K562 (p53-null and T/G for mdm2 SNP309). We also examined mdm2 gene-splicing patterns in these lines by cloning and sequencing analyses.RESULTS:
While Mdm2-overexpressing G/G cells were resistant to p53 activation by DNA damage, they were sensitive to Nutlin-3. Strikingly, the p53 G1 checkpoint in G/G cells was activated by Nutlin-3 but not by etoposide, whereas in other Mdm2-overexpressing cells, both drugs activated p53 and subsequent G1 arrest or apoptosis. cDNA clones lacking exons 5-9 were generated at a high frequency in cells overexpressing Mdm2.CONCLUSION:
Nutlin-3 and DNA damage distinguish a differential phenotype in human cancer cells with G/G mdm2 SNP309 from other Mdm2 overexpressers. Categorization of the Mdm2 isoforms produced and their influence on p53 activity will help in characterization and treatment development for different cancers.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Piperazinas
/
Proteína Supressora de Tumor p53
/
Proteínas Proto-Oncogênicas c-mdm2
/
Imidazóis
/
Neoplasias
Limite:
Humans
Idioma:
En
Revista:
Ethn Dis
Assunto da revista:
CIENCIAS SOCIAIS
/
SAUDE PUBLICA
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Estados Unidos