title: Retinoblastoma-independent regulation of cell proliferation and senescence by the p53-p21 axis in lamin A /C-depleted cells.
abstract: The expression of A-type lamin is downregulated in several cancers, and lamin defects are the cause of several diseases including a form of accelerated aging. We report that depletion of lamin A/C expression in normal human cells leads to a dramatic downregulation of the Rb family of tumor suppressors and a defect in cell proliferation. Lamin A/C-depleted cells exhibited a flat morphology and accumulated markers of cellular senescence. This senescent phenotype was accompanied by engagement of the p53 tumor suppressor and induction of the p53 target gene p21 and was prevented by small hairpin RNAs against p53, p21, or by the oncoprotein Mdm2. The expression of E2F target genes, normally required for cell cycle progression, was downregulated after lamin A/C depletion but restored after the inactivation of p53. A similar senescence response was observed in myoblasts from a patient with a lamin A mutation causing muscular dystrophy. We thus reveal a previously unnoticed mechanism of controlling cell cycle genes expression, which depends on p53 but does not require the retinoblastoma family of tumor suppressors and that can be relevant to understand the pathogenesis of laminopathies and perhaps aging.
authors.affiliation: Biochemistry Department, Université de Montréal, Montréal, QC, Canada.
authors.forename: Olga
authors.initials: O
authors.lastname: Moiseeva
authors.forename: Véronique
authors.initials: V
authors.lastname: Bourdeau
authors.forename: Mathieu
authors.initials: M
authors.lastname: Vernier
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Dabauvalle
authors.forename: Gerardo
authors.initials: G
authors.lastname: Ferbeyre
mesh_terms: D015415:Biomarkers; D059447:Cell Cycle Checkpoints; D002460:Cell Line; D049109:Cell Proliferation; D016922:Cellular Senescence; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D004249:DNA Damage; D050687:E2F1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D050703:E2F2 Transcription Factor / Q000235:genetics / Q000378:metabolism; D050699:E2F3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D006801:Humans; D034904:Lamin Type A / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009154:Mutation; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D015415:Biomarkers; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D050703:E2F2 Transcription Factor; C493761:E2F2 protein, human; D050699:E2F3 Transcription Factor; C098319:E2F3 protein, human; D034904:Lamin Type A; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C440308:lamin C; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2