APR-246 reactivates mutant p53 by targeting cysteines 124 and 277

Cell Death Dis. 2018 May 1;9(5):439. doi: 10.1038/s41419-018-0463-7.


The TP53 tumor suppressor gene is frequently inactivated in human tumors by missense mutations in the DNA binding domain. TP53 mutations lead to protein unfolding, decreased thermostability and loss of DNA binding and transcription factor function. Pharmacological targeting of mutant p53 to restore its tumor suppressor function is a promising strategy for cancer therapy. The mutant p53 reactivating compound APR-246 (PRIMA-1Met) has been successfully tested in a phase I/IIa clinical trial. APR-246 is converted to the reactive electrophile methylene quinuclidinone (MQ), which binds covalently to p53 core domain. We identified cysteine 277 as a prime binding target for MQ in p53. Cys277 is also essential for MQ-mediated thermostabilization of wild-type, R175H and R273H mutant p53, while both Cys124 and Cys277 are required for APR-246-mediated functional restoration of R175H mutant p53 in living tumor cells. These findings may open opportunities for rational design of novel mutant p53-targeting compounds.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Aza Compounds / chemistry*
  • Bridged Bicyclo Compounds, Heterocyclic / chemistry*
  • Cell Line, Tumor
  • Cysteine / chemistry
  • Humans
  • Mutation, Missense
  • Protein Domains
  • Protein Stability
  • Tumor Suppressor Protein p53 / chemistry*
  • Tumor Suppressor Protein p53 / genetics


  • Aza Compounds
  • Bridged Bicyclo Compounds, Heterocyclic
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • 2,2-bis(hydroxymethyl)-1-azabicyclo(2,2,2,)octan-3-one
  • Cysteine