title: HDACs and the senescent phenotype of WI-38 cells.
abstract: BACKGROUND
  Normal cells possess a limited proliferative life span after which they enter a state of irreversible growth arrest. This process, known as replicative senescence, is accompanied by changes in gene expression that give rise to a variety of senescence-associated phenotypes. It has been suggested that these gene expression changes result in part from alterations in the histone acetylation machinery. Here we examine the influence of HDAC inhibitors on the expression of senescent markers in pre- and post-senescent WI-38 cells.
  
  
  RESULTS
  Pre- and post-senescent WI-38 cells were treated with the HDAC inhibitors butyrate or trichostatin A (TSA). Following HDAC inhibitor treatment, pre-senescent cells increased p21WAF1 and beta-galactosidase expression, assumed a flattened senescence-associated morphology, and maintained a lower level of proteasome activity. These alterations also occurred during normal replicative senescence of WI-38 cells, but were not accentuated further by HDAC inhibitors. We also found that HDAC1 levels decline during normal replicative senescence.
  
  
  CONCLUSIONS
  Our findings indicate that HDACs impact numerous phenotypic changes associated with cellular senescence. Reduced HDAC1 expression levels in senescent cells may be an important event in mediating the transition to a senescent phenotype.
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, USA. place.robert@gmail.com
authors.forename: Robert F
authors.initials: RF
authors.lastname: Place
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Noonan
authors.forename: Charles
authors.initials: C
authors.lastname: Giardina
mesh_terms: D002087:Butyrates; D002460:Cell Line; D048430:Cell Shape / Q000187:drug effects; D016922:Cellular Senescence / Q000187:drug effects*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology* / Q000201:enzymology; D005786:Gene Expression Regulation; D056284:Histone Deacetylase 1; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000032:analysis / Q000502:physiology*; D006801:Humans; D006877:Hydroxamic Acids; D008168:Lung / Q000166:cytology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D002087:Butyrates; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; C012589:trichostatin A; D001616:beta-Galactosidase; D046988:Proteasome Endopeptidase Complex; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases