Induction of p53-dependent senescence by the MDM2 antagonist nutlin-3a in mouse cells of fibroblast origin.
Cellular senescence is emerging as an important in vivo anticancer response elicited by multiple stresses, including currently used chemotherapeutic drugs. Nutlin-3a is a recently discovered small-molecule antagonist of the p53-destabilizing protein murine double minute-2 (MDM2) that induces cell cycle arrest and apoptosis in cancer cells with functional p53. Here, we report that nutlin-3a induces cellular senescence in murine primary fibroblasts, oncogenically transformed fibroblasts, and fibrosarcoma cell lines. No evidence of drug-induced apoptosis was observed in any case. Nutlin-induced senescence was strictly dependent on the presence of functional p53 as revealed by the fact that cells lacking p53 were completely insensitive to the drug, whereas cells lacking the tumor suppressor alternative reading frame product of the CDKN2A locus underwent irreversible cell cycle arrest. Interestingly, irreversibility was achieved in neoplastic cells faster than in their corresponding parental primary cells, suggesting that nutlin-3a and oncogenic signaling cooperate in activating p53. Our current results suggest that senescence could be a major cellular outcome of cancer therapy by antagonists of the p53-MDM2 interaction, such as nutlin-3a.
Molecular Oncology Program, Spanish National Cancer Research Center (CNIO), Madrid, Spain.
Alejo
A
Efeyan
Ana
A
Ortega-Molina
Susana
S
Velasco-Miguel
Daniel
D
Herranz
Lyubomir T
LT
Vassilev
Manuel
M
Serrano
D020823:ADP-Ribosylation Factor 1 / Q000235:genetics / Q000502:physiology; D000818:Animals; D002453:Cell Cycle; D016922:Cellular Senescence; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D005354:Fibrosarcoma / Q000378:metabolism / Q000473:pathology*; D007093:Imidazoles / Q000494:pharmacology*; D051379:Mice; D018345:Mice, Knockout; D010879:Piperazines / Q000494:pharmacology*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*
C493957:Cdkn1a protein, mouse; C417743:Cdkn2a protein, mouse; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D007093:Imidazoles; D010879:Piperazines; D016159:Tumor Suppressor Protein p53; C482205:nutlin 3; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2; D020823:ADP-Ribosylation Factor 1