Targeting codon 158 p53-mutant cancers via the induction of p53 acetylation

Area of Science:

• Oncology
• Molecular Biology
• Cancer Genetics

Background:

• Gain-of-function (GOF) mutations in the TP53 tumor suppressor gene, particularly in the DNA binding domain (DBD), promote cancer by upregulating chromatin regulatory genes.
• The p53 codon 158 (Arg158) mutation is a prevalent DBD GOF mutation in lung carcinomas, driving oncogenic mechanisms.

Purpose of the Study:

• To investigate the therapeutic potential of targeting the oncogenic mechanisms driven by the p53 Arg158 GOF mutation.
• To identify therapeutic strategies that exploit the specific vulnerabilities created by this mutation.

Main Methods:

• High-throughput compound screening to identify potential therapeutic agents.
• Combination analyses to evaluate synergistic effects of different treatments.
• Molecular assays to elucidate the mechanism of action, including effects on DNA binding, gene expression, and signaling pathways.

Main Results:

• Acetylation of mutant p53 (mutp53) at Arg158 sensitizes cancer cells to cisplatin-induced DNA damage.
• Acetylation of mutp53R158G alters its DNA binding motifs and upregulates TRAIP, an E3 ubiquitin ligase.
• TRAIP dephosphorylates IκB, inhibiting nuclear factor kappa-B (NF-κB) signaling and promoting apoptosis.
• This therapeutic vulnerability is specific to Arg158-mutp53 tumors and not observed in p53 wild-type or other GOF mutp53 cells.

Conclusions:

• Targeted acetylation of mutp53R158G in combination with DNA-damaging agents represents a promising, tumor-specific therapeutic strategy for lung carcinomas harboring this mutation.
• This approach exploits a unique oncogenic mechanism, offering a novel avenue for precision cancer medicine.