Chalcone derivatives antagonize interactions between the human oncoprotein MDM2 and p53

Area of Science:

• Biochemistry
• Molecular Biology
• Oncology

Background:

• The MDM2 oncoprotein inhibits the p53 tumor suppressor protein by binding to its transactivation domain.
• Inactivation of the p53 gene, through mutation or oncogenic protein binding, is common in human tumors.
• MDM2 overexpression can inactivate p53 in tumors like soft tissue sarcomas, compromising genome integrity and promoting cell cycle progression.

Purpose of the Study:

• To identify novel inhibitors of the MDM2/p53 interaction.
• To explore the therapeutic potential of disrupting this interaction for cancer treatment.

Main Methods:

• Multidimensional NMR spectroscopy to characterize chalcone binding to human MDM2.
• Biochemical assays to assess the disruption of p53/MDM2 complexes.

Main Results:

• Chalcones were identified as inhibitors that bind to a specific subsite within the p53 binding cleft of MDM2.
• These chalcones effectively disrupted both free and DNA-bound p53/MDM2 protein complexes.
• The disruption led to the release of p53, restoring its transcriptional activity.

Conclusions:

• Chalcones represent a promising starting point for structure-based drug design targeting the MDM2/p53 interaction.
• Disrupting the MDM2/p53 binding offers a viable therapeutic strategy for cancers where p53 is inactivated by MDM2 overexpression.
• Restoration of p53 activity through MDM2 inhibition can re-establish the genome integrity checkpoint.