title: Senescent cells in growing tumors: population dynamics and cancer stem cells.
abstract: Tumors are defined by their intense proliferation, but sometimes cancer cells turn senescent and stop replicating. In the stochastic cancer model in which all cells are tumorigenic, senescence is seen as the result of random mutations, suggesting that it could represent a barrier to tumor growth. In the hierarchical cancer model a subset of the cells, the cancer stem cells, divide indefinitely while other cells eventually turn senescent. Here we formulate cancer growth in mathematical terms and obtain predictions for the evolution of senescence. We perform experiments in human melanoma cells which are compatible with the hierarchical model and show that senescence is a reversible process controlled by survivin. We conclude that enhancing senescence is unlikely to provide a useful therapeutic strategy to fight cancer, unless the cancer stem cells are specifically targeted.
authors.affiliation: Department of Biomolecular Science and Biotechnology, University of Milano, Milano, Italy.
authors.forename: Caterina A M
authors.initials: CA
authors.lastname: La Porta
authors.forename: Stefano
authors.initials: S
authors.lastname: Zapperi
authors.forename: James P
authors.initials: JP
authors.lastname: Sethna
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D048708:Cell Growth Processes / Q000502:physiology; D015687:Cell Hypoxia / Q000502:physiology; D045744:Cell Line, Tumor; D016922:Cellular Senescence / Q000502:physiology*; D016000:Cluster Analysis; D019295:Computational Biology; D003198:Computer Simulation; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism; D008545:Melanoma / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D059630:Mesenchymal Stem Cells / Q000166:cytology; D008954:Models, Biological; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000166:cytology* / Q000378:metabolism; D013269:Stochastic Processes; D000077022:Survivin; D014162:Transfection; D014183:Transplantation, Heterologous
chemical_list: C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D009363:Neoplasm Proteins; D000077022:Survivin