title: Induction of extracellular matrix-remodeling genes by the senescence-associated protein APA-1.
abstract: Human fibroblasts undergo cellular senescence after a finite number of divisions, in response to the erosion of telomeres. In addition to being terminally arrested in the cell cycle, senescent fibroblasts express genes that are normally induced upon wounding, including genes that remodel the extracellular matrix. We have identified the novel zinc finger protein APA-1, whose expression increased in senescent human fibroblasts independent of telomere shortening. Extended passage, telomerase-immortalized fibroblasts had increased levels of APA-1 as well as the cyclin-dependent kinase inhibitor p16. In fibroblasts, APA-1 was modified by the ubiquitin-like protein SUMO-1, which increased APA-1 half-life, possibly by blocking ubiquitin-mediated degradation. Overexpression of APA-1 did not cause cell cycle arrest; but, it induced transcription of the extracellular matrix-remodeling genes MMP1 and PAI2, which are associated with fibroblast senescence. MMP1 and PAI2 transcript levels also increased in telomerase-immortalized fibroblasts that had high levels of APA-1, demonstrating that the matrix-remodeling phenotype of senescent fibroblasts was not induced by telomere attrition alone. APA-1 was able to transactivate and bind to the MMP1 promoter, suggesting that APA-1 is a transcription factor that regulates expression of matrix-remodeling genes during fibroblast senescence.
authors.affiliation: Program in Cancer Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Benanti
authors.forename: Dawnnica K
authors.initials: DK
authors.lastname: Williams
authors.forename: Kristin L
authors.initials: KL
authors.lastname: Robinson
authors.forename: Harvey L
authors.initials: HL
authors.lastname: Ozer
authors.forename: Denise A
authors.initials: DA
authors.lastname: Galloway
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D016922:Cellular Senescence; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D003546:Cysteine Endopeptidases; D004268:DNA-Binding Proteins; D005109:Extracellular Matrix / Q000378:metabolism / Q000502:physiology*; D005347:Fibroblasts / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding; D020033:Protein Isoforms; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D012190:Retroviridae / Q000235:genetics; D025842:SUMO-1 Protein / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D019098:Telomerase / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D004268:DNA-Binding Proteins; D009097:Multienzyme Complexes; D020033:Protein Isoforms; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D025842:SUMO-1 Protein; D014157:Transcription Factors; D025801:Ubiquitin; C467905:ZNF410 protein, human; D003513:Cycloheximide; D008156:Luciferases; D019098:Telomerase; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex