title: SCH529074, a small molecule activator of mutant p53, which binds p53 DNA binding domain (DBD), restores growth-suppressive function to mutant p53 and interrupts HDM2-mediated ubiquitination of wild type p53.
abstract: Abrogation of p53 function occurs in almost all human cancers, with more than 50% of cancers harboring inactivating mutations in p53 itself. Mutation of p53 is indicative of highly aggressive cancers and poor prognosis. The vast majority of mutations in p53 occur in its core DNA binding domain (DBD) and result in inactivation of p53 by reducing its thermodynamic stability at physiological temperature. Here, we report a small molecule, SCH529074, that binds specifically to the p53 DBD in a saturable manner with an affinity of 1-2 microm. Binding restores wild type function to many oncogenic mutant forms of p53. This small molecule reactivates mutant p53 by acting as a chaperone, in a manner similar to that previously reported for the peptide CDB3. Binding of SCH529074 to the p53 DBD is specifically displaced by an oligonucleotide with a sequence derived from the p53-response element. In addition to reactivating mutant p53, SCH529074 binding inhibits ubiquitination of p53 by HDM2. We have also developed a novel variant of p53 by changing a single amino acid in the core domain of p53 (N268R), which abolishes binding of SCH529074. This amino acid change also inhibits HDM2-mediated ubiquitination of p53. Our novel findings indicate that through its interaction with p53 DBD, SCH529074 restores DNA binding activity to mutant p53 and inhibits HDM2-mediated ubiquitination.
authors.affiliation: Department of Tumor Biology, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA. Mark.Demma@spcorp.com
authors.forename: Mark
authors.initials: M
authors.lastname: Demma
authors.forename: Eugene
authors.initials: E
authors.lastname: Maxwell
authors.forename: Robert
authors.initials: R
authors.lastname: Ramos
authors.forename: Lianzhu
authors.initials: L
authors.lastname: Liang
authors.forename: Cheng
authors.initials: C
authors.lastname: Li
authors.forename: David
authors.initials: D
authors.lastname: Hesk
authors.forename: Randall
authors.initials: R
authors.lastname: Rossman
authors.forename: Alan
authors.initials: A
authors.lastname: Mallams
authors.forename: Ronald
authors.initials: R
authors.lastname: Doll
authors.forename: Ming
authors.initials: M
authors.lastname: Liu
authors.forename: Cynthia
authors.initials: C
authors.lastname: Seidel-Dugan
authors.forename: W Robert
authors.initials: WR
authors.lastname: Bishop
authors.forename: Bimalendu
authors.initials: B
authors.lastname: Dasmahapatra
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001665:Binding Sites; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects*; D047369:Chromatin Immunoprecipitation; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D008819:Mice, Nude; D018832:Molecular Chaperones; D009154:Mutation / Q000235:genetics*; D010879:Piperazines / Q000302:isolation & purification / Q000494:pharmacology*; D011485:Protein Binding; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics / Q000378:metabolism*; D011799:Quinazolines / Q000302:isolation & purification / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism*; D054875:Ubiquitination; D023041:Xenograft Model Antitumor Assays
chemical_list: D018832:Molecular Chaperones; D010879:Piperazines; D011799:Quinazolines; D012333:RNA, Messenger; C549329:SCH 529074; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D004247:DNA; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2