The expression of the ADAMs proteases in prostate cancer cell lines and their regulation by dihydrotestosterone

The ADAMs are a multi-functional gene family, some of which have been shown to play a role in diverse biological processes such as fertilization, myog enesis, neurogenesis and the activation of growth factors/immune regulators such as TNF-alpha. So-named because they possess both A Disintegrin And Me talloprotease domain, the ADAMs have potential implications for the metasta sis of human tumour cells via cell adhesion and protease activities. Howeve r, no studies have yet comprehensively examined the expression or regulatio n of ADAMs in solid tumours. Therefore, the aim of this study was to examin e the expression of the ADAMs in human prostate cancer cell lines and to ex amine their possible regulation by androgen, a primary hormonal regulator o f prostate cancer cell proliferation and metastasis. Applying RT-PCR, ADAM- 9, -10, -11, -15 and -17 mRNA expression was found in the androgen-dependen t prostate cancer cell lines, LNCaP and ALVA-41 and the androgen-independen t cell lines, DU-145 and PC-3. Northern blotting of LNCaP cell total RNA re vealed transcripts for ADAM-9 (3.8 kb), ADAM-IO (4.4, 3.2 and 0.54 kb), ADA M-15 (3 kb) and ADAM-17 (4 and 2.6 kb). ADAM-11 transcript was not detected by Northern blotting possibly due to low levels of ADAM-11 mRNA expression . This is the first report of ADAM expression in prostate cancer cell lines . Since androgens are implicated in prostate cancer cell growth and mainten ance, the regulation of ADAMs by dihydrotestosterone (DHT) was investigated in the androgen-dependent cell line LNCaP. It was shown by quantitative RT -PCR using continuous fluorescence monitoring that ADAM-IO mRNA expression was regulated in a bell shaped, dose-dependent manner by DHT. Maximum stimu lation was observed at 1.0 nM DHT (5-fold significant increase). For ADAM-9 mRNA, a significant upregulation was found at 1.0 and 10 nM (1.5-1.7-fold increase). In contrast, ADAM-17 mRNA, was significantly inhibited at 0.1 an d 1.0 nM (1.7-fold decrease). This is the first report, to our knowledge, i llustrating hormonal regulation of ADAM mRNA. The novel data described here also provide a strong stimulus to the development of specific quantitative and functional assays for particular ADAMs. These assays, which are not ye t available, are required to enable subsequent investigation, both in vitro and in vivo, of the specific roles of each ADAM in prostate cancer cell pr oliferation, cell motility and invasion. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.