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Oncotarget. 2018 Dec 14;9(98):37137-37156. doi: 10.18632/oncotarget.26440. eCollection 2018 Dec 14.

The molecular mechanism of action of methylene quinuclidinone and its effects on the structure of p53 mutants.

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Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
Department of Physics, Faculty of Science, University of Alberta, Edmonton, Alberta, Canada.
Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Torino, Italy.


One of the most important tumor suppressor proteins in eukaryotic cells is the transcription factor called p53. The importance of this protein in cells comes from the fact that it regulates a wide variety of cellular processes including the cell cycle, metabolism, DNA repair, senescence and apoptosis. In cancer cells, p53 is a major target as the most mutated protein, which has led to the search for potential activators of the mutant protein. Currently, the only mutated-p53 activator in clinical trials is a small molecule called APR-246. There is evidence that the active metabolite of APR-246 binds covalently to mutant p53 and restores its wild-type (wt) activity. In this work, we created atomistic in silico models of the wt, mutant and drugged mutant p53 proteins each in complex with DNA. Using molecular dynamics simulations we generated equilibrated models of the complexes. Detailed analysis revealed that the binding of the APR-246 active metabolite to the mutant proteins alters their interaction with DNA. In particular, the binding of the molecule at loop L1 of the protein allows the loop to anchor the protein to DNA similarly to wt p53. Several important p53-DNA interactions lost due to mutation were also restored in the drugged mutants. These findings, not only provide a possible mechanism of action of this drug, but also criteria to use in virtual screening campaigns for other p53 activators.


R175H mutant p53; R273H mutant p53; mechanism of action; methylene quinuclidinone; p53

Conflict of interest statement

CONFLICTS OF INTEREST All authors confirm no competing financial or other interests.

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