Regulation of u‐PA gene expression in human prostate cancer

• Published in: International journal of cancer Vol. 94; no. 3; pp. 390 - 395
• Main Authors: Evans, Christopher P., Stapp, Eschelle C., Dall'Era, Marc A., Juarez, Jose, Yang, Joy C.
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 01.11.2001; Wiley-Liss
• Subjects: androgen; Biological and medical sciences; Blotting, Northern; Blotting, Western; Cell Division; Chloramphenicol O-Acetyltransferase - metabolism; Coloring Agents - pharmacology; Down-Regulation; Flutamide - pharmacology; Gene Expression Regulation, Neoplastic; Genes, Reporter; Humans; Male; MAP Kinase Signaling System; Medical sciences; Mutation; Nephrology. Urinary tract diseases; Promoter Regions, Genetic; prostate cancer; Prostatic Neoplasms - genetics; Prostatic Neoplasms - metabolism; Recombinant Fusion Proteins - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA - metabolism; Signal Transduction; Tetrazolium Salts - pharmacology; Thiazoles - pharmacology; Time Factors; Transcription, Genetic; transcriptional regulation; Transfection; Tumor Cells, Cultured; Tumors of the urinary system; Urinary tract. Prostate gland; urokinase; Urokinase-Type Plasminogen Activator - biosynthesis; Urokinase-Type Plasminogen Activator - genetics; Human; u-Plasminogen activator; Urinary system disease; Carcinoma; Prostate disease; Serine endopeptidases; Androgen; Enzyme; Transcription promoter; Malignant tumor; Gene expression; Peptidases; Signal transduction; Regulation(control); Established cell line; Genetics; Hydrolases; Sex steroid hormone; Male genital diseases; Prostate; Transcription factor AP1
• DOI: 10.1002/ijc.1469
• ISSN: 0020-7136

u‐PA contributes to CaP progression, especially in the metastatic androgen‐insensitive state. In vitro, u‐PA is expressed by androgen‐insensitive, but not androgen‐sensitive, CaP cell lines. We hypothesized that in androgen‐sensitive CaP an activated ARE represses u‐PA expression but in androgen‐insensitive CaP this repression is lost and u‐PA is upregulated through MAP kinase signaling pathways. To determine whether binding of the DHT–AR complex to AREs in the u‐PA promoter region represses u‐PA transcription in androgen‐sensitive CaP, we studied 2 PC3 androgen‐insensitive human CaP cell lines stably transfected with AR [PC3(AR)2 and PC3(AR)13] and 1 mock‐transfected cell line [PC3(M)]. In the presence of the synthetic androgen mibolerone, both PC3(AR)2 and PC3(AR)13, but not PC3(M), cells showed decreased u‐PA expression as assayed by Western and Northern blotting. The AR inhibitor flutamide abrogated mibolerone's effect. Androgen regulation of a second gene, PSA, was also demonstrated in the PC3(AR)2 cell line. To explore the pathway stimulating u‐PA expression in CaP, we performed transient transfections in PC3(AR)2 cells using u‐PA promoter‐regulated CAT reporter constructs. Compared to full‐length u‐PA promoter–CAT constructs, either deletion or mutation of the 5′ AP‐1 or PEA3 site reduced CAT expression. The location of androgen responsiveness in the u‐PA promoter was not identified through the combination of promoter search and transient transfection assays, indicating that a more complicated mechanism is involved in the AR‐mediated downmodulation of u‐PA expression. © 2001 Wiley‐Liss, Inc.