Abstact

Designing metabolically stable peptides to target interactions of the tumor suppressor protein p53 with the two oncogenic proteins MDM2 and MDMX represents an attractive approach to harvesting "high-hanging fruits" often inaccessible to traditional anticancer drug discovery and development efforts. Here, we report the design of a proteolysis-resistant d-dodecapeptide, termed DPMI-ω (EFWYVEp-ClFEKLLR), capable of disrupting the p53-MDM2/MDMX complex by antagonizing MDM2 and MDMX. DPMI-ω, upon fabrication on gold nanoparticles, efficiently traversed tumor cells and killed them by reactivating the p53 signaling pathway. Further, DPMI-ω inhibited B16 melanoma growth in vivo and, when combined with an anti-PD1 antibody, powerfully augmented the efficacy of immunotherapy by expanding CD3+/CD8+ cytotoxic T cells and suppressing CD4+/CD25+ regulatory T cells. Our work validates the design of a therapeutically viable anticancer peptide, showcasing its potential in combination therapy to treat patients with tumors that are otherwise resistant or poorly responsive to antitumor immunotherapy.