Modulating p53 condensation rewires transcriptional programs to enhance tumor suppression

Restoring wild-type p53 has long been viewed as a direct route to cancer therapy, yet clinical efforts have delivered only modest benefit. Here, we show that a critical but underappreciated aspect of p53 biology is its ability to form biomolecular condensates that can be manipulated to selectively enhance specific properties. The modest benefit of current p53-dependent therapeutics stems, in part, from the dual nature of p53; alongside canonical tumor-suppressor genes, wild-type p53 also boosts neuron-associated genes that can foster malignancy. Using live-cell super-resolution imaging we find that endogenous p53 nucleates novel ∼50-nm condensates. Coactivators reinforce droplets, whereas antagonists dissolve them, revealing a previously unappreciated regulatory layer. Guided by these mechanisms, we engineered liquid-liquid phase separation (LLPS)-enhanced p53 constructs with greater condensation propensity (LLPSEp53s). These condensates act as a mesoscale hub that biases promoter occupancy and partner selection. Intriguingly, LLPSEp53s tilt the transcriptome, preferentially strengthening tumor-suppressive transcription while dampening neuro-oncogenic outputs. LLPSEp53s suppress proliferation across multiple cancer cell lines, including those refractories to wild-type p53, and curtails melanoma growth in immunocompetent mice without added toxicity. Our findings establish phase separation as an adjustable layer of p53 target selectivity and highlight condensate engineering as a tractable strategy to unleash the full antitumor potential of p53.