A new genotoxicity assay based on p53 target gene induction

Area of Science:

• Molecular Biology
• Genetics
• Toxicology

Background:

• The p53 protein acts as a key sensor of DNA damage, regulating cellular responses.
• Transcriptional induction of p53 target genes serves as an early indicator of genotoxic stress.
• Li-Fraumeni syndrome patients exhibit compromised DNA damage responses due to TP53 mutations.

Purpose of the Study:

• To establish a common p53-dependent transcriptional signature of DNA damage.
• To develop a rapid and reliable assay for measuring genotoxicity.
• To identify genotoxic potential of therapeutic agents, particularly for vulnerable patient groups.

Main Methods:

• Expression microarrays and RNA-Seq analysis on human lymphocytes (wild-type and TP53-mutant).
• Exposure of lymphocytes to various genotoxic agents (physical and chemical).
• Quantitative measurement of selected p53 target gene induction in response to agents.

Main Results:

• A conserved p53-dependent transcriptional signature of DNA damage was identified.
• A novel p53 genotoxicity assay was successfully developed and validated.
• Most common cancer therapeutics, excluding microtubule poisons, were found to be highly genotoxic.

Conclusions:

• The p53 genotoxicity assay provides a sensitive method for assessing chemical and physical agent genotoxicity.
• This assay can help identify non-genotoxic drugs, reducing secondary malignancy risks.
• The assay is particularly beneficial for patients with DNA damage repair deficiencies, such as those with Li-Fraumeni syndrome.