Abstract
<title>Abstract</title> <p>Missense mutations in TP53 frequently promote conformational destabilization and amyloid-like aggregation, contributing to tumor progression and resistance to therapy. Although mutant p53 aggregation has emerged as a potential therapeutic target, pharmacological strategies capable of directly suppressing this process remain limited. Here, we identify RCT-13 as an inhibitor of mutant p53 aggregation. In triple-negative breast cancer (TNBC) cells harboring the p53 R280K mutation, RCT-13 reduces intracellular aggregation, restores tumor-suppressive signaling, inhibits migration, and induces apoptosis in a p53-dependent manner. Mechanistically, biochemical and mass spectrometric analyses demonstrate that RCT-13 forms cysteine-dependent covalent adducts with the p53 core domain, preventing aggregation of the mutant protein in vitro. Importantly, treatment of xenograft tumors with RCT-13 reduces mutant p53 aggregation in vivo, as evidenced by decreased DO-1/A11 colocalization. Together, these findings establish covalent targeting of aggregation-prone cysteine residues as a strategy to suppress mutant p53 aggregation and restore apoptotic competence in cancer cells. Our results identify mutant p53 aggregation as a pharmacologically tractable vulnerability and support the development of covalent modulators of p53 conformation as potential therapeutic agents for p53-driven cancers.</p>