title: Quantitative proteomics reveals that Hsp90 inhibition preferentially targets kinases and the DNA damage response.
abstract: Despite the increasing importance of heat shock protein 90 (Hsp90) inhibitors as chemotherapeutic agents in diseases such as cancer, their global effects on the proteome remain largely unknown. Here we use high resolution, quantitative mass spectrometry to map protein expression changes associated with the application of the Hsp90 inhibitor, 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG). In depth data obtained from five replicate SILAC experiments enabled accurate quantification of about 6,000 proteins in HeLa cells. As expected, we observed activation of a heat shock response with induced expression of molecular chaperones, which refold misfolded proteins, and proteases, which degrade irreparably damaged polypeptides. Despite the broad range of known Hsp90 substrates, bioinformatics analysis revealed that particular protein classes were preferentially affected. These prominently included proteins involved in the DNA damage response, as well as protein kinases and especially tyrosine kinases. We followed up on this observation with a quantitative phosphoproteomic analysis of about 4,000 sites, which revealed that Hsp90 inhibition leads to much more down- than up-regulation of the phosphoproteome (34% down versus 6% up). This study defines the cellular response to Hsp90 inhibition at the proteome level and sheds light on the mechanisms by which it can be used to target cancer cells.
authors.affiliation: Departments of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
authors.forename: Kirti
authors.initials: K
authors.lastname: Sharma
authors.forename: R Martin
authors.initials: RM
authors.lastname: Vabulas
authors.forename: Boris
authors.initials: B
authors.lastname: Macek
authors.forename: Stefan
authors.initials: S
authors.lastname: Pinkert
authors.forename: Jürgen
authors.initials: J
authors.lastname: Cox
authors.forename: Matthias
authors.initials: M
authors.lastname: Mann
authors.forename: F Ulrich
authors.initials: FU
authors.lastname: Hartl
mesh_terms: D016227:Benzoquinones / Q000494:pharmacology*; D019295:Computational Biology; D004249:DNA Damage / Q000187:drug effects*; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D047029:Lactams, Macrocyclic / Q000494:pharmacology*; D018832:Molecular Chaperones / Q000378:metabolism; D010748:Phosphopeptides / Q000032:analysis / Q000378:metabolism; D017510:Protein Folding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D020543:Proteome / Q000032:analysis / Q000378:metabolism*; D040901:Proteomics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D016227:Benzoquinones; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D018832:Molecular Chaperones; D010748:Phosphopeptides; D020543:Proteome; C448659:17-(dimethylaminoethylamino)-17-demethoxygeldanamycin; D011505:Protein-Tyrosine Kinases