PSMA‐Triggered Phase Separation of Peptide‐Drug Conjugates Enables Zinc‐Dependent Tumor Inhibition

Abstract Peptide‐drug conjugates (PDC) have emerged as a promising modality for targeted tumor therapy, offering high specificity, and design flexibility. However, the therapeutic efficacy of PDC is often limited by rapid systemic clearance, inadequate control over drug release kinetics, and difficulty in forming stable drug‐tumor interfaces in vivo. These challenges highlight the need for next‐generation PDC systems capable of spatiotemporal regulation and enhanced pharmacological activity. In this study, a structurally adaptive PDC platform termed LE‐HOA was developed based on cascade reconstruction induced by liquid‐liquid phase separation (LLPS). This platform was constructed by covalently linking a tumor‐targeting peptide (LE) ligand with the inhibitor 4‐(hydroxyamino)‐4‐oxobutanoic acid (HOA). LE‐HOA could self‐assemble into nanomicelles under physiological conditions, enhancing drug stability during circulation. Under PSMA induction, HOA was exposed through disassembly, which in turn inhibited the zinc‐dependent enzymatic activity of PSMA. This further induced LLPS, resulting in the rapid formation of nanofiber that expanded drug‐tumor recognition interface. Both in vitro and in vivo studies demonstrated that LE‐HOA enabled sustained pharmacological signaling and effective tumor suppression with good biosafety. These findings suggest a new strategy to address limitations in PDC therapeutics by integrating intelligent response and dynamic phase behavior for enhanced lesion‐targeted action.