title: Characterization of the p53-rescue drug CP-31398 in vitro and in living cells.
abstract: The Pfizer compound CP-31398 has been reported to stabilize the core domain of the tumour suppressor p53 in vitro and be an effective anti-cancer drug by virtue of rescuing destabilized mutants of p53. We did not detect any interaction between the p53 core domain and CP-31398 in vitro by a wide range of quantitative biophysical techniques over a wide range of conditions. CP-31398 did not stabilize p53 in our experiments. However, we found that CP-31398 intercalated with DNA and also altered and destabilized the DNA-p53 core domain complex. We analysed by NMR TROSY the interaction of the domain with a DNA oligomer and identified the changes in the complex on the binding of CP-31398. CP-31398 also decreased sequence-specific DNA binding of wild-type p53 and His-273 mutant p53. CP-31398 had a non-specific toxic effect independent of mutant p53 expression in several cell lines carrying Tet-regulated mutant p53. CP-31398 caused a small increase in MDM-2 expression and a more pronounced p53-independent increase in Bax expression. CP-31398 did, however, induce the PAb1620 epitope (characteristic of native p53) in cells expressing His-175 mutant p53. This was prevented by cycloheximide, suggesting that any stabilizing action of CP-31398 would have to be on newly synthesized p53. One of the unstable mutants that was reported to have been rescued by CP-31398, R249S, does not bind DNA when folded at lower temperatures.
authors.affiliation: Cambridge University Chemical Laboratory and Cambridge Center for Protein Engineering, MRC Centre, Hills Road, Cambridge CB2 2QH, UK.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Rippin
authors.forename: Vladimir J N
authors.initials: VJ
authors.lastname: Bykov
authors.forename: Stefan M V
authors.initials: SM
authors.lastname: Freund
authors.forename: Galina
authors.initials: G
authors.lastname: Selivanova
authors.forename: Klas G
authors.initials: KG
authors.lastname: Wiman
authors.forename: Alan R
authors.initials: AR
authors.lastname: Fersht
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D002152:Calorimetry, Differential Scanning; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004355:Drug Stability; D016158:Genes, p53 / Q000235:genetics; D006801:Humans; D013058:Mass Spectrometry; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D011743:Pyrimidines / Q000737:chemistry / Q000494:pharmacology*; D013696:Temperature; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D011743:Pyrimidines; D016159:Tumor Suppressor Protein p53; D004247:DNA; C402665:CP 31398