Glucocorticoid (GC)-mediated down-regulation of urokinase plasminogen activator expression via the serum and GC regulated kinase-1/forkhead box O3a pathway.
The glucocorticoid receptor (GR) and its ligand, cortisol, play a central role in human physiology. The exact mechanisms by which GR activation regulates these processes are the subject of intensive investigation. We and others have shown that GR activation can indirectly down-regulate specific genes via serum and glucocorticoid (GC) regulated kinase-1-mediated inhibition of forkhead box O3a (FOXO3a) transcriptional activity. We previously used gene expression microarrays, together with bioinformatic analyses, to identify putative FOXO3a target genes in breast epithelial cells. In this paper we refine our analysis through the use of FOXO3a chromatin immunoprecipitation (ChIP) microarrays. ChIP microarray results reveal urokinase plasminogen activator (uPA) as a putative novel target of FOXO3a in breast epithelial and breast cancer cell lines. We further show that uPA down-regulation after GC treatment requires serum and GC regulated kinase-1-mediated inactivation of FOXO3a activity. ChIP and luciferase assays confirm that FOXO3a can both occupy and transactivate the uPA promoter. Our data suggest that inactivation of FOXO3a after GR activation is an important mechanism contributing to GC-mediated repression of uPA gene expression in breast epithelial and cancer cells.
Pew
Travis
T
Department of Medicine and Committee on Cancer Biology, University of Chicago, 5841 South Maryland Avenue, MC 2115, Chicago, Illinois 60637, USA.
Zou
Min
M
Brickley
Deanna R
DR
Conzen
Suzanne D
SD
D001665:Binding Sites; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D017124:Conserved Sequence; D003907:Dexamethasone / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D017874:Immediate-Early Proteins / Q000502:physiology*; D042361:Mammary Glands, Human / Q000378:metabolism; D008954:Models, Biological; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics* / Q000378:metabolism; D000099184:Serum-Glucocorticoid Regulated Kinases
D003907:Dexamethasone; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D005938:Glucocorticoids; D017874:Immediate-Early Proteins; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; D014568:Urokinase-Type Plasminogen Activator; D000099184:Serum-Glucocorticoid Regulated Kinases; C499517:FOXO3 protein, human