Mutant TRP53 exerts a target gene-selective dominant-negative effect to drive tumor development

Area of Science:

• Molecular Biology
• Cancer Research
• Genetics

Background:

• Mutations in the tumor suppressor gene Trp53 are common in human cancers.
• These mutations are thought to promote cancer through dominant-negative effects (DNEs) or neomorphic gain-of-function (GOF) activities.

Purpose of the Study:

• To investigate the mechanisms by which Trp53 mutations drive lymphomagenesis.
• To differentiate the roles of DNEs and GOF activities in Trp53-driven tumorigenesis.

Main Methods:

• Studied five TRP53 mutants in a mouse model of lymphomagenesis.
• Utilized RNA sequencing to analyze gene expression changes.
• Assessed the impact of mutant TRP53 on DNA repair, proliferation, and metabolism pathways.

Main Results:

• TRP53 mutants did not accelerate lymphomagenesis alone but synergized with c-MYC overexpression.
• The DNE of mutant TRP53 disproportionately affected a subset of wild-type TRP53 target genes, rather than globally repressing them.
• Mutant TRP53 impaired DNA repair, proliferation, and metabolism pathways in premalignant cells.

Conclusions:

• In lymphomagenesis, mutant TRP53 primarily drives tumorigenesis through DNEs.
• DNEs modulate wild-type TRP53 function in a way that favors neoplastic transformation.