Healthy aging can be promoted by enhanced metabolic fitness and physical capacity. Mitochondria are chief metabolic organelles with strong implications in aging that also coordinate broad physiological functions, in part, using peptides that are encoded within their independent genome. However, mitochondrial-encoded factors that actively regulate aging are unknown. Here, we report that mitochondrial-encoded MOTS-c can significantly enhance physical performance in young (2 mo.), middle-age (12 mo.), and old (22 mo.) mice. MOTS-c can regulate (i) nuclear genes, including those related to metabolism and proteostasis, (ii) skeletal muscle metabolism, and (iii) myoblast adaptation to metabolic stress. We provide evidence that late-life (23.5 mo.) initiated intermittent MOTS-c treatment (3x/week) can increase physical capacity and healthspan in mice. In humans, exercise induces endogenous MOTS-c expression in skeletal muscle and in circulation. Our data indicate that aging is regulated by genes encoded in both of our co-evolved mitochondrial and nuclear genomes.

Copy number alteration (CNA) profiling of human tumors has revealed recurrent patterns of DNA amplifications and deletions across diverse cancer types. These patterns are suggestive of conserved selection pressures during tumor evolution but cannot be fully explained by known oncogenes and tumor suppressor genes. Using a pan‐cancer analysis of CNA data from patient tumors and experimental systems, here we show that principal component analysis‐defined CNA signatures are predictive of glycolytic phenotypes, including 18F‐fluorodeoxy‐glucose (FDG) avidity of patient tumors, and increased proliferation. The primary CNA signature is enriched for p53 mutations and is associated with glycolysis through coordinate amplification of glycolytic genes and other cancer‐linked metabolic enzymes. A pan‐cancer and cross‐species comparison of CNAs highlighted 26 consistently altered DNA regions, containing 11 enzymes in the glycolysis pathway in addition to known cancer‐driving genes. Furthermore, exogenous expression of hexokinase and enolase enzymes in an experimental immortalization system altered the subsequent copy number status of the corresponding endogenous loci, supporting the hypothesis that these metabolic genes act as drivers within the conserved CNA amplification regions. Taken together, these results demonstrate that metabolic stress acts as a selective pressure underlying the recurrent CNAs observed in human tumors, and further cast genomic instability as an enabling event in tumorigenesis and metabolic evolution.

Metabolic reprogramming in cancer cells can increase their dependence on metabolic substrates such as glucose. As such, the vulnerability of cancer cells to glucose deprivation creates an attractive opportunity for therapeutic intervention. Because it is not possible to starve tumors of glucose in vivo, here we sought to identify the mechanisms in glucose deprivation–induced cancer cell death and then designed inhibitor combinations to mimic glucose deprivation–induced cell death. Using metabolomic profiling, we found that cells undergoing glucose deprivation–induced cell death exhibited dramatic accumulation of intracellular l-cysteine and its oxidized dimer, l-cystine, and depletion of the antioxidant GSH. Building on this observation, we show that glucose deprivation–induced cell death is driven not by the lack of glucose, but rather by l-cystine import. Following glucose deprivation, the import of l-cystine and its subsequent reduction to l-cysteine depleted both NADPH and GSH pools, thereby allowing toxic accumulation of reactive oxygen species. Consistent with this model, we found that the glutamate/cystine antiporter (xCT) is required for increased sensitivity to glucose deprivation. We searched for glycolytic enzymes whose expression is essential for the survival of cancer cells with high xCT expression and identified glucose transporter type 1 (GLUT1). Testing a drug combination that co-targeted GLUT1 and GSH synthesis, we found that this combination induces synthetic lethal cell death in high xCT-expressing cell lines susceptible to glucose deprivation. These results indicate that co-targeting GLUT1 and GSH synthesis may offer a potential therapeutic approach for targeting tumors dependent on glucose for survival.

Nucleotide synthesis regulates epithelial cell senescence Supporting Fig. 1: Senescent HMEC are frequently multi-nucleated. Videos from 3D reconstructions of Z-stack confocal imaging for HMEC cells stained with Hoechst dye (blue) and plasma membrane dye (yellow) for HMEC at PD 10 (A) and HMEC at PD 37 (B, C). Nucleotide synthesis regulates epithelial cell senescenceNucleotide synthesis regulates epithelial cell senescence Supporting Fig. 2: Extracellular medium analysis of amino acid and TCA cycle metabolites, intracellular AMP/ATP levels, and MSEA analysis of senescent HMEC intracellular metabolite pools A) Extracellular metabolite secretion data for TCA cycle metabolites in proliferating and senescent HMEC. Metabolite extracts from blank and conditioned media were analyzed by LC-MS. Secretion or uptake values were normalized to integrated cell number. Secreted metabolites have positive values, and consumed metabolites have negative values. * denotes p-value less than 0.05 by FDR-corrected Student's t-test. See Supporting Table S1 for all measured metabolites. B) Same as in A for amino acids. * denotes p-value less than 0.05 by FDR-corrected Student's t-test. See Supporting Table S1 for all measured metabolites. C) Intracellular pool sizes of AMP and ATP of proliferating and senescent HMEC. * denotes p-value less than 0.05 by FDR-corrected Student's t-test. See Supporting Table S2 for all measured metabolites. D) Metabolite set enrichment analysis (MSEA) analysis for intracellular metabolites pool sizes of proliferating and senescent HMEC. Metabolites were ranked based on log2 fold change of senescent/proliferating. Shown are the mountain plot of nucleoside mono/di/tri-phosphates (left), and table of all tested metabolic pathways (right). Supporting Fig. 7: Glucose fractional incorporation analysis of luciferase-and hTERT-expressing HMEC at low and high population doublings. Volcano plots representing the average log2 fold change versus the FDR-corrected p-value of [U-13 C]glucose fractional contribution for: A) Senescent luciferase-(Day ~45) v. proliferating hTERT-expressing HMEC (Day ~45). B) Senescent luciferase-(Day ~45) v. proliferating luciferase-expressing HMEC (Day ~15). C) Proliferating hTERT-(Day ~45) v. proliferating hTERT-expressing HMEC (Day ~15). D) Proliferating luciferase-(Day ~15) v. proliferating hTERT-expressing HMEC (Day ~15). Days represent the time since completion of drug selection following viral infection. Nucleotide synthesis regulates epithelial cell senescence Supporting Fig. 8: Metabolite set enrichment analysis of hTERT immortalization. MSEA analysis for fractional contribution of [U-13 C]-glucose in hTERT immortalized HMEC. Metabolites were ranked based on log2 fold change of luciferase/hTERT. Nucleotide synthesis regulates epithelial cell senescence Nucleotide synthesis regulates epithelial cell senescence Supporting Fig. 9: Inhibition of RRM2 induces senescence in HMEC and MCF10A cells. A) Western blots of p21, PAI-1, and actin for triapine-treated HMEC. Blots represent five inde...