Poster Presentation International Peptide Symposium 2023

Reactivation of the p53 pathway in cancer cells using a grafted cyclotide (#259)

Yen-Hua Crystal Huang 1 , Grégoire Philippe 1 2 , Anna Mittermeier 3 , Chris Brown 4 , Quentin Kaas 1 , Siti Radhiah Ramlan 4 , Conan K Wang 1 , David Lane 4 , Alexander Loewer 3 , Sonia Troeira Henriques 2 , David J Craik 1
  1. Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia
  2. School of Biomedical Sciences, Queensland University of Technology, Translational Research Institute, Brisbane, Queensland, Australia
  3. Technical University Darmstadt, 64287, Darmstadt, Germany
  4. A*STAR, IMCB , DITL lab, 8A Biomedical Grove, #06-06, Immunos,, 138648, Singapore

Peptides are promising drug modalities due to their ability to modulate protein–protein interfaces, but their application is limited by their unpredictable ability to reach the cytosol. Here we focus on improving the delivery of a peptide sequence, mimicking the p53 transactivation domain, that binds to MDM2 and MDMX, using the cyclotide MCoTI-II as a scaffold. We applied several design strategies to improve intracellular delivery and found that conjugation of the lead compound to the cyclic cell penetrating peptide cR10 was the most effective. The conjugation allowed cell internalization at low micromolar concentration and led to elevated intracellular p53 levels and cell apoptosis in A549, MCF7 and HCT116 reporter cancer cell lines without causing membrane disruption. This work demonstrates a >35-fold improvement of cyclotide delivery without undesirable side effects.