Mutant p53 protein accumulation is selectively targetable by proximity-inducing drugs

TP53 mutant cancers are associated with approximately half of cancer deaths. The most common mechanism of p53 inactivation involves missense mutations. Such mutations in TP53 result in a robust upregulation of the p53 protein. Here, we demonstrate an induced proximity approach to selectively kill TP53 mutant cells. This approach uses the increased abundance of p53 protein in TP53 mutant cancer cells to concentrate toxic molecules in these cells. We demonstrate this approach with a molecule that binds the Y220C mutant of p53 and concentrates a PLK1 inhibitor in cells harboring TP53^Y220C mutations. The resulting bifunctional molecule promotes formation of a p53^Y220C-PLK1 ternary complex, mislocalizes PLK1, inhibits PLK1 activity, elicits selective G2/M arrest and induces apoptosis in TP53^Y220C cells while sparing wild-type TP53 cells. These data exemplify a potentially generalizable framework for targeting TP53 missense mutations by leveraging mutant p53 protein abundance to induce cell death, independent of p53's transcriptional activity.