title: Glucocorticoid-modulated gene expression of tissue- and urinary-type plasminogen activator and plasminogen activator inhibitor 1 and 2.
abstract: Constitutive gene expression of four components of plasminogen activating enzyme system, urinary and tissue-type plasminogen activator (u-PA and t-PA), plasminogen activator inhibitor 1 (PAI-1) and PAI-2 in HT-1080 human fibrosarcoma cells, was modulated by the synthetic glucocorticoid dexamethasone (Dex, 10(-7) M). More than 90% of u-PA, t-PA and PAI-1 antigen was found in conditioned medium, whereas PAI-2 was mainly cell associated. In 48-h culture supernatants (expressed per 10(6) cells) PAI-1 antigen increased from 350 to 3,300 ng and t-PA from 19 to 38 ng. u-PA and PAI-2 in the same samples decreased from 380 to 46 ng and from 3.5 to 1.8 ng, respectively. Northern blot hybridization and nuclear "Run-on" transcription assays demonstrated that the increase of t-PA and PAI-1 and the decrease of u-PA were associated with equivalent changes of gene template activity. Modulation of u-PA, t-PA and PAI-1 gene expression by Dex was completely blocked by the glucocorticoid antagonist RU 38486, suggesting that all effects were mediated through the glucocorticoid receptor. Cycloheximide, an inhibitor of protein biosynthesis induced a rapid transient increase of t-PA, u-PA and PAI-1 mRNA and a sustained increase of PAI-2 mRNA, but blocked the more long term effects of Dex, suggesting that both constitutive and hormonally regulated maintenance of mRNA steady state levels required protein biosynthesis.
mesh_terms: D003513:Cycloheximide / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology*; D004963:Estrenes / Q000494:pharmacology; D005354:Fibrosarcoma; D005786:Gene Expression Regulation / Q000187:drug effects*; D005796:Genes; D005938:Glucocorticoids / Q000037:antagonists & inhibitors; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D015735:Mifepristone; D009693:Nucleic Acid Hybridization; D010960:Plasminogen Activators / Q000037:antagonists & inhibitors / Q000235:genetics*; D015849:Plasminogen Inactivators; D012333:RNA, Messenger / Q000032:analysis; D013698:Templates, Genetic; D010959:Tissue Plasminogen Activator / Q000235:genetics*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D004963:Estrenes; D005938:Glucocorticoids; D006023:Glycoproteins; D015849:Plasminogen Inactivators; D012333:RNA, Messenger; D015735:Mifepristone; D003907:Dexamethasone; D003513:Cycloheximide; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator