Mutant p53^K120R expression enables a partial capacity to modulate metabolism

Area of Science:

• Molecular Biology
• Cancer Research
• Metabolic Regulation

Background:

• The TP53 tumor suppressor gene is crucial for preventing cancer by regulating apoptosis, cell cycle arrest, and metabolism.
• TP53 mutations are common in cancer, affecting its tumor-suppressive functions.
• Specific TP53 mutations, like K120R, may retain some functions while losing others, particularly regarding apoptosis and metabolism.

Purpose of the Study:

• To investigate the metabolic regulation properties of the human P53 K120R mutant.
• To compare the transcriptional specificity and metabolic phenotype of P53 K120R with wild-type P53 and other mutants (3KR, R273H).
• To analyze the induction of P53 targets and proteins involved in the antioxidant response.

Main Methods:

• Utilized yeast- and mammalian-based reporter assays to assess transcriptional specificity.
• Analyzed the metabolic phenotype in colon cancer HCT116 cells expressing different P53 variants.
• Measured the induction of P53 targets and antioxidant response proteins.

Main Results:

• P53 K120R mutant selectively activates cell cycle arrest genes, not apoptotic targets.
• The K120R mutant exhibits partial transactivation of the metabolic target TIGAR.
• All P53 mutants showed uncoupled oxygen consumption and ATP production, with increased lipid peroxidation compared to wild-type P53.

Conclusions:

• The P53 K120R mutant displays selective functionality, preserving cell cycle arrest activity while losing apoptotic regulation.
• While K120R partially modulates glucose metabolism and limits lipid peroxidation compared to other mutants, it cannot fully counteract oxidative stress.
• Wild-type P53 is essential for completely counteracting oxidative stress and associated damages.