title: Metabolic analysis of senescent human fibroblasts reveals a role for AMP in cellular senescence.
abstract: Cellular senescence is considered a major tumour-suppressor mechanism in mammals, and many oncogenic insults, such as the activation of the ras proto-oncogene, trigger initiation of the senescence programme. Although it was shown that activation of the senescence programme involves the up-regulation of cell-cycle regulators such as the inhibitors of cyclin-dependent kinases p16INK4A and p21CIP-1, the mechanisms underlying the senescence response remain to be resolved. In the case of stress-induced premature senescence, reactive oxygen species are considered important intermediates contributing to the phenotype. Moreover, distinct alterations of the cellular carbohydrate metabolism are known to contribute to oncogenic transformation, as is best documented for the phenomenon of aerobic glycolysis. These findings suggest that metabolic alterations are involved in tumourigenesis and tumour suppression; however, little is known about the metabolic pathways that contribute to these processes. Using the human fibroblast model of in vitro senescence, we analysed age-dependent changes in the cellular carbohydrate metabolism. Here we show that senescent fibroblasts enter into a metabolic imbalance, associated with a strong reduction in the levels of ribonucleotide triphosphates, including ATP, which are required for nucleotide biosynthesis and hence proliferation. ATP depletion in senescent fibroblasts is due to dysregulation of glycolytic enzymes, and finally leads to a drastic increase in cellular AMP, which is shown here to induce premature senescence. These results suggest that metabolic regulation plays an important role during cellular senescence and hence tumour suppression.
authors.affiliation: Institute for Biomedical Aging Research, Austrian Academy of Sciences, Rennweg 10, A-6020 Innsbruck, Austria.
authors.forename: Werner
authors.initials: W
authors.lastname: Zwerschke
authors.forename: Sybille
authors.initials: S
authors.lastname: Mazurek
authors.forename: Petra
authors.initials: P
authors.lastname: Stöckl
authors.forename: Eveline
authors.initials: E
authors.lastname: Hütter
authors.forename: Erich
authors.initials: E
authors.lastname: Eigenbrodt
authors.forename: Pidder
authors.initials: P
authors.lastname: Jansen-Dürr
mesh_terms: D000249:Adenosine Monophosphate / Q000494:pharmacology* / Q000502:physiology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D016922:Cellular Senescence; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006019:Glycolysis; D006801:Humans; D017136:Ion Transport; D000090063:Proto-Oncogene Mas; D011522:Protons; D012265:Ribonucleotides / Q000378:metabolism
chemical_list: C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011522:Protons; D012265:Ribonucleotides; D000249:Adenosine Monophosphate