V600E B-Raf requires the Hsp90 chaperone for stability and is degraded in response to Hsp90 inhibitors
Open Access
- 21 December 2005
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 103 (1) , 57-62
- https://doi.org/10.1073/pnas.0609973103
Abstract
The Raf family includes three members, of which B-Raf is frequently mutated in melanoma and other tumors. We show that Raf-1 and A-Raf require Hsp90 for stability, whereas B-Raf does not. In contrast, mutated, activated B-Raf binds to an Hsp90–cdc37 complex, which is required for its stability and function. Exposure of melanoma cells and tumors to the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin results in the degradation of mutant B-Raf, inhibition of mitogen-activated protein kinase activation and cell proliferation, induction of apoptosis, and antitumor activity. These data suggest that activated mutated B-Raf proteins are incompetent for folding in the absence of Hsp90, thus suggesting that the chaperone is required for the clonal evolution of melanomas and other tumors that depend on this mutation. Hsp90 inhibition represents a therapeutic strategy for the treatment of melanoma.Keywords
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