Diverse rescue potencies of p53 mutations to ATO are predetermined by intrinsic mutational properties

Abstract

Tumor suppressor p53 is inactivated by thousands of heterogeneous mutations in cancer, but their individual druggability remains largely elusive. Here, we evaluated 800 common p53 mutants for their rescue potencies by the representative generic rescue compound arsenic trioxide (ATO) in terms of transactivation activity, cell growth inhibition, and mouse tumor–suppressive activities. The rescue potencies were mainly determined by the solvent accessibility of the mutated residue, a key factor determining whether a mutation is a structural one, and the temperature sensitivity, the ability to reassemble the wild-type DNA binding surface at a low temperature, of the mutant protein. A total of 390 p53 mutants were rescued to varying degrees and thus were termed as type 1, type 2a, and type 2b mutations, depending on the degree to which they were rescued. The 33 type 1 mutations were rescued to amounts comparable to the wild type. In PDX mouse trials, ATO preferentially inhibited growth of tumors harboring type 1 and type 2a mutants. In an ATO clinical trial, we report the first-in-human mutant p53 reactivation in a patient harboring the type 1 V272M mutant. In 47 cell lines derived from 10 cancer types, ATO preferentially and effectively rescued type 1 and type 2a mutants, supporting the broad applicability of ATO in rescuing mutant p53. Our study provides the scientific and clinical communities with a resource of the druggabilities of numerous p53 mutations ( www.rescuep53.net ) and proposes a conceptual p53-targeting strategy based on individual mutant alleles rather than mutation type.

AcGlcAs: A Novel P53-Targeting Arsenical with Potent Cellular Uptake and Cancer Cell Selectivity

“…In the RNA-seq assay in U937 cells harboring arsenic-rescuable p53-V272M (Figure C–F and Table S2), the DEGs that were upregulated by 0.1 and 0.3 μM AcGlcAs treatment were predominantly enriched in “Direct p53 effectors” in the NCI-Nature database and “p53 Pathway” in MSigDB_Hallmark databases (Figure C, red bars, P = 1.6 × 10 –17 and 1.4 × 10 –34 for 0.1 μM AcGlcAs, respectively; P = 2.8 × 10 –14 and 1.8 × 10 –29 for 0.3 μM AcGlcAs, respectively). Indeed, a larger number of the 116 established p53 targets were upregulated by AcGlcAs (Figure D–F).…”

“…Indeed, a larger number of the 116 established p53 targets were upregulated by AcGlcAs (Figure D–F). To ensure that the observed upregulation of p53 target genes is indeed caused by binding of As to p53-V272M, we further applied an arsenic-binding defected p53-C124R mutant, in which one cysteine of the arsenic-binding pocket is mutated, , as a control in RNA-seq. Consequently, the DEGs upregulated by both 0.1 and 0.3 μM AcGlcAs in the p53-C124R cells are poorly enriched in the p53-related pathway (Figure C).…”

“…In the RNA-seq assay in U937 cells harboring arsenicrescuable p53-V272M 60 (Figure 6C−F and Table S2), the DEGs that were upregulated by 0.1 and 0. These results in V272M and C124C isogenic cell lines strongly suggest that AcGlcAs exhibits a high degree of binding specificity toward the C124-C135-C141 pocket of p53.…”

High throughput evaluation of genetic variants with prime editing sensor libraries

“…5d). These results demonstrate that prime editing sensor screens could be used to systematically identify variant-specific vulnerabilities to diverse therapies, augmenting cDNA-based approaches for performing similar screens 54 .…”

New clinical trial design in precision medicine: discovery, development and direction

“… 413 Arsenic trioxide, an approved therapeutic drug for acute promyelocytic leukemia, causes unfoldable p53 structural mutations to fold and restore its tumor inhibition function in the balance of denaturation and renaturation by releasing arsenic atoms and covalently bonding DNA-binding sites and β-sandwich domain in p53. 413 , 414 Based on the logic of “from mutation itself to mutation subtype”, researchers have evaluated more than 800 TP53 mutants and found that 390 of them could be rescued by arsenic trioxide, of which 33 restored activities similar to the wild-type. 414 The “PANDA” (P53 AND As) pan-cancer basket trial is currently being conducted to further verify the therapeutic value of arsenic trioxide in solid tumors with TP53 structural mutations.…”