p53 mutants G245S and R337H associated with the Li-Fraumeni syndrome regulate distinct metabolic pathways

Li-Fraumeni and Li-Fraumeni-like syndromes (LFS/LFL) are hereditary cancer predisposition disorders associated with germline mutations in the TP53 tumor suppressor gene. Here, we stably expressed LFS/LFL-associated p53 mutants R337H and G245S in p53-null H1299 cells to study their cellular and molecular effects. Mutant proteins showed distinct oligomerization states and opposing effects on cell proliferation and viability. Stable expression of p53^G245S enhanced cell proliferation and spheroid formation, while cells stably expressing p53^R337H showed reduced proliferation and clonogenicity, along with increased cell death. Mass spectrometry analysis revealed that proteins whose expression was induced by p53^R337H or p53^G245S expression were related to distinct metabolic profiles. Proteins upregulated by p53^G245S expression were associated with a Warburg phenotype, while proteins upregulated by p53^R337H expression were related to oxidative phosphorylation and fatty acid oxidation. Differences in mitochondrial mass and activity between cells stably expressing p53^R337H or p53^G245S were further corroborated by High Resolution Respirometry, flow cytometry and qPCR assays. The implications of the different oncogenic properties of p53^R337H and p53^G245S on the clinical manifestation and treatment of LFS/LFL patients carrying these mutations are discussed.