Hsp90 is essential for restoring cellular functions of temperature-sensitive p53 mutant protein but not for stabilization and activation of wild-type p53: implications for cancer therapy
Language English Country United States Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
15613472
DOI
10.1074/jbc.m412767200
PII: S0021-9258(19)62783-3
Knihovny.cz E-resources
- MeSH
- Transcription, Genetic MeSH
- Nuclear Proteins genetics MeSH
- Protein Conformation MeSH
- Humans MeSH
- Mutation * MeSH
- Cell Line, Tumor MeSH
- Tumor Suppressor Protein p53 genetics metabolism physiology MeSH
- Neoplasms pathology MeSH
- HSP90 Heat-Shock Proteins metabolism physiology MeSH
- Proto-Oncogene Proteins c-mdm2 MeSH
- Proto-Oncogene Proteins genetics MeSH
- Gene Expression Regulation, Neoplastic MeSH
- Temperature * MeSH
- Feedback, Physiological MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Nuclear Proteins MeSH
- MDM2 protein, human MeSH Browser
- Tumor Suppressor Protein p53 MeSH
- HSP90 Heat-Shock Proteins MeSH
- Proto-Oncogene Proteins c-mdm2 MeSH
- Proto-Oncogene Proteins MeSH
Several signaling pathways that monitor the dynamic state of the cell converge on the tumor suppressor p53. The ability of p53 to process these signals and exert a dynamic downstream response in the form of cell cycle arrest and/or apoptosis is crucial for preventing tumor development. This p53 function is abrogated by p53 gene mutations leading to alteration of protein conformation. Hsp90 has been implicated in regulating both wild-type and mutant p53 conformations, and Hsp90 antagonists are effective for the therapy of some human tumors. Using cell lines that contain human tumor-derived temperature-sensitive p53 mutants we show that Hsp90 is required for both stabilization and reactivation of mutated p53 at the permissive temperature. A temperature decrease to 32 degrees C causes conversion to a protein conformation that is capable of inducing expression of MDM2, leading to reduction of reactivated p53 levels by negative feedback. Mutant reactivation is enhanced by simultaneous treatment with agents that stabilize the reactivated protein and is blocked by geldanamycin, a specific inhibitor of Hsp90 activity, indicating that Hsp90 antagonist therapy and therapies that act to reactivate mutant p53 will be incompatible. In contrast, Hsp90 is not required for maintaining wild-type p53 or for stabilizing wild-type p53 after treatment with chemotherapeutic agents, indicating that Hsp90 therapy might synergize with conventional therapies in patients with wild-type p53. Our data demonstrate the importance of the precise characterization of the interaction between p53 mutants and stress proteins, which may shed valuable information for fighting cancer via the p53 tumor suppressor pathway.
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