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Study breakdown

Novel Peptide Stapling Method Creates Potent Dual Inhibitors of Cancer-Promoting MDM2/MDMX Proteins

In VitroPreliminary evidence
The takeaway

A multicomponent reaction-based peptide stapling approach generated stapled peptides with potent dual inhibition of MDM2 and MDMX — two key proteins that disable the p53 tumor suppressor.

Dual MDM2/MDMX inhibition

MCR-stapled peptides simultaneously block both cancer-promoting proteins from disabling p53

What the researchers found

MCR-based stapled peptides achieved potent dual antagonism of MDM2 and MDMX binding to p53, with crystal structures demonstrating direct staple-protein interactions that contribute to binding affinity.

Why it matters

MDM2 and MDMX both suppress p53, and dual inhibition is needed to fully reactivate this tumor suppressor. This versatile stapling method enables rapid generation of diverse, potent dual inhibitors.

The numbers in context

Dual MDM2/MDMX antagonists; multiple cocrystal structures; Ugi multicomponent reaction stapling

How the study worked

Multicomponent reaction (Ugi) peptide stapling with diversity generation at the cross-linker. Activity assessed by fluorescence polarization, microscale thermophoresis, and 2D NMR. Multiple co-crystal structures solved with MDM2.

Who was studied

Not applicable (chemistry and structural biology study)

What this study cannot tell us

In vitro biochemical and structural studies only. No cell-based or animal data on anti-cancer activity. Pharmacokinetics, cell penetration, and in vivo stability not assessed.

How to read the evidence

Preliminary — strong biochemical and structural data but no cellular or in vivo anti-cancer evidence.

When this study was published

Published in 2020; stapled peptide drug development continues with several candidates in clinical trials for various targets.

The bigger picture

Reactivating p53 is one of the most pursued strategies in cancer drug development. Stapled peptides offer advantages over small molecules for targeting the large, flat protein-protein interaction surfaces involved.

Questions still open

  • Do these MCR-stapled peptides penetrate cancer cell membranes and reactivate p53 in cellular assays?
  • How do the pharmacokinetic properties compare to existing stapled peptide drugs?
  • Can this MCR stapling approach be applied to other protein-protein interaction targets?

Common questions

What are stapled peptides?
Stapled peptides have a chemical bridge (staple) connecting two points in the peptide chain, locking it into a helical shape. This improves stability, cell penetration, and binding to target proteins compared to unstapled peptides.
Why target both MDM2 and MDMX?
Both MDM2 and MDMX bind and disable p53, the most important tumor suppressor. Cancer cells often use both proteins to keep p53 inactive, so effective p53 reactivation requires blocking both simultaneously.

Read the original research

Multicomponent Peptide Stapling as a Diversity-Driven Tool for the Development of Inhibitors of Protein-Protein Interactions.

Angewandte Chemie (International ed. in English), 59(13), 5235-5241

Citation

Ricardo, Manuel G; Ali, Ameena M; Plewka, Jacek; Surmiak, Ewa; Labuzek, Beata; Neochoritis, Constantinos G; Atmaj, Jack; Skalniak, Lukasz; Zhang, Ran; Holak, Tad A; Groves, Matthew; Rivera, Daniel G; Dömling, Alexander. (2020). Multicomponent Peptide Stapling as a Diversity-Driven Tool for the Development of Inhibitors of Protein-Protein Interactions.. Angewandte Chemie (International ed. in English), 59(13), 5235-5241. https://doi.org/10.1002/anie.201916257