An Effective Virtual Screening Protocol to Identify Promising p53-MDM2 Inhibitors

The p53–MDM2 interaction is a well-known protein–protein contact, and its disruption is a key event for p53 activation and induction of its oncosuppressor response. The design of small molecules that can block the p53–MDM2 interaction and reactivate the p53 function is a promising strategy for cancer therapy. To date, several compounds have been identified as p53–MDM2 inhibitors, and X-ray structures of MDM2 complexed with several ligands are available in the Brookhaven Protein Data Bank. These data have been exploited to compile a hierarchical virtual screening protocol. The first steps were aimed at selecting a focused library, which was submitted in parallel to docking and pharmacophore model alignment. Selected compounds were subjected to inhibition assays of both cellular vitality (MTT) and p53–MDM2 interaction (ELISA and co-immunoprecipitation), disclosing four nanomolar inhibitors.