Metabolic reprogramming in Li-Fraumeni Syndrome underlies the pre-cancer niche and cancer predisposition

Li-Fraumeni Syndrome (LFS) is a hereditary cancer predisposition syndrome associated with germline mutations in TP53 (mutp53). Mutp53 abrogates normal tumor-suppressive functions, including DNA repair, metabolism, and apoptosis. The accumulation of these effects, along with clonal expansion of metabolically reprogrammed cells, can enhance cell survival and adaptation to stress conditions, priming a pre-cancerous niche. We hypothesize that germline TP53 mutations alter metabolism to promote a pre-cancerous primed state. Moreover, metabolic interventions can reverse this state to reduce cancer onset in LFS. LFS ( Trp53 +/R172H ) mice and wild-type (WT) littermates were followed across four age cohorts (60, 120, 210, 300 days) and treated with metformin-supplemented drinking water (1mg/mL) or left untreated. At endpoint, plasma, muscle, liver, kidney, spleen, thymus, and brain tissues were collected. Flow cytometry immune profiling was performed on spleen and thymus. All tissues were analyzed by LC-MS/MS untargeted proteomics and Seahorse metabolic assays. All statistics were performed in R. Splenic lymphocyte proportions did not differ between LFS and WT mice across development, however we did observe significantly different metabolic states (p<0.05). LFS mice expressed significantly higher metabolism-associated functional exhaustion markers KLRG1 and PD1 on NK cells and CD4+ T cells, respectively. Metformin treatment rescued this phenotype by significantly reduced PD1 expression on exhausted T cells (CD4+, CD8+, and CD4+CD8+ double-positive; p<0.05) in LFS mice. Tissue proteomics revealed key metabolic and developmental pathway differences in LFS mice, and the effect of longitudinal metformin on the pre-cancer niche. These pathways are being further validated through in vitro assays with patient-derived cells to help delineate the role of various cell types in LFS pre-cancer priming. We demonstrated that metabolic reprogramming occurs systemically in LFS to promote a cancer-primed state. Moreover, treatment with a metabolic modulator can aid in rescuing these changes, suggesting potential a potential cancer interception or treatment for LFS patients to revert the cancer priming phenotype.