A nano-predator of pathological MDMX construct by clearable supramolecular gold(I)-thiol-peptide complexes achieves safe and potent anti-tumor activity

As alternatives to small-molecular proteolysis-targeting chimeras (PROTAC), peptide-based molecular glues (MG) are a broad range of dual-functional ligands that simultaneously bind with targetable proteins and E3 ligases by mimicking proteinprotein interaction (PPI) partners. Methods: Herein, we design a peptide-derived MG to target a tumor-driving protein, MDMX, for degradation, and nanoengineered it into a supramolecular gold(I)-thiol-peptide complex (Nano-MP) to implement the proteolysis recalcitrance, cellular internalization, and glutathione-triggered release. To optimize the tumor targeting, a pH-responsive macromolecule termed polyacryl sulfydryl imidazole (PSI) was synthesized to coat Nano-MP. Results: As expected, Nano-MP@PSI induced the MDMX degradation by ubiquitination and subsequently restored the anti-cancer function of p53 and p73. Nano-MP@PSI revealed potent anti-cancer activities in an orthotopic xenograft mouse model of retinoblastoma by intraocular injection and a patient-derived xenograft model of malignant pancreatic cancer by systemic injection, while maintaining a favorable safety profile and showing a highly favorable clearable profile of excretion from the living body. Conclusion: Collectively, this work not only provided a clinically viable paradigm for the treatment of a wide variety of tumors by multiple administration types, but, more importantly, it bridged the chasm between peptides and PROTACs, and likely reinvigorated the development of peptide-derived proteolysis-targeting chimeras for a great variety of diseases.