CRISPR/Cas9-Induced DNA Damage Enriches for Mutations in a p53-Linked Interactome: Implications for CRISPR-Based Therapies.

Abstract

Inactivating <i>p53</i> mutations are the most abundant genetic alterations found in cancer. Here we show that CRISPR/Cas9-induced double-stranded DNA breaks enrich for cells deficient in <i>p53</i> and in genes of a core CRISPR-p53 tumor suppressor interactome. Such enrichment could predispose to cancer development and thus pose a challenge for clinical CRISPR use. Transient p53 inhibition could suppress the enrichment of cells with these mutations. The level of DNA damage response induced by an sgRNA influenced the enrichment of <i>p53</i>-deficient cells and could be a relevant parameter in sgRNA design to limit cellular enrichment. Furthermore, a dataset of >800 human cancer cell lines identified additional factors influencing the enrichment of <i>p53</i>-mutated cells, including strong baseline <i>CDKN1A</i> expression as a predictor for an active CRISPR-p53 axis. Taken together, these data provide details about p53 biology in the context of CRISPR-induced DNA damage and identify strategies to enable safer CRISPR use. SIGNIFICANCE: CRISPR-mediated DNA damage enriches for cells with escape mutations in a core CRISPR-p53 interactome, which can be suppressed by transient inhibition of p53.