The Prostate 67:722^ 731 (2007) Reactive Oxygen Species Mediate Androgen Receptor- and Serum Starvation-Elicited Downstream Signaling of ADAM9 Expression in Human Prostate Cancer Cells Katsumi Shigemura, 1 Shian-Ying Sung, 1 Hiroyuki Kubo, 1 Rebecca S. Arnold, 2 Masato Fujisawa, 3 Akinobu Gotoh, 4 Haiyen E. Zhau, 1 and Leland W.K. Chung 1 * 1 Molecular Urology and Therapeutics Program, Department of Urology,Winship Cancer Institute, Emory University School of Medicine, Atlanta,Georgia 2 Department of Pathology, Emory University School of Medicine, Atlanta,Georgia 3 Division of Urology, Department of OrganTherapeutics, Faculty of Medicine, Kobe University Graduate School of Medicine, Kobe, Japan 4 Laboratory of Cell and GeneTherapy, Institute for Advanced Medical Sciences, Hyogo College of Medicine, Nishinomiya, Japan BACKGROUND: The A Disintegrin And Metalloprotease (ADAM) family is a group of transmembrane proteins containing cell adhesive and proteolytic functional domains. ADAM9 expression was shown to be mediated by androgen receptor (AR) and stress conditions. This study determined a common mediator responsible for ADAM9 protein regulation which supports human prostate cancer (PCa) cell growth and survival. METHODS: ADAM9 protein expression was measured under androgen, anti-androgen, hydrogen peroxide, and/or serum starvation conditions in PCa cells. The roles of reactive oxygen species (ROS) were assessed in the presence or absence of recombinant catalase, or in cells stably transfected with either catalase- or a control neo-cDNA expression vector. ROS was assayed by dihydroethidium (DHE) followed by FACS analysis. RESULTS: ADAM9 protein expression was upregulated by androgen in AR-positive but not in AR-negative PCa cells. The anti-androgen bicalutamide effectively blocked this induction. While serum starvation enhanced ADAM9 expression in AR-positive PCa cells, this stress condition did not alter ADAM9 expression in AR-negative PCa cells. Parallel results also showed that androgen treatment or serum starvation enhanced ROS only in AR-positive but not in AR-negative PCa cells. ROS appears to be a common downstream mediator of androgen- or serum starvation-induced ADAM9 expression since addition of hydrogen peroxide or introduction of catalase, either enhanced or abolished respectively ADAM9 protein expression by both AR-positive and -negative PCa cells. Abbreviations: PCa, prostate cancer; ADAM, a disintegrin and metalloprotease; AD, androgen-dependent; AI, androgen-indepen- dent; AR, androgen receptor; ECM, extracellular matrix; FBS, fetal bovine serum; DMSO, dimethyl sulfoxide; ROS, reactive oxygen species; 5a-DHT, 5a-dihydrotestosterone; DHE, dihydroethidium; EF-1a, elongation factor 1-alpha; PBS, phosphate-buffered saline; BSA, bovine serum albumin. Grant sponsor: NIH; Grant numbers: 1PO1 CA098912, DAMD17-03- 2-0033, PC0420260, 5P20GM072069, 1RO1 CA108468; Grant sponsor: Georgia Cancer Coalition. *Correspondence to: Leland W.K. Chung, Molecular Urology and Therapeutics Program, Department of Urology, Winship Cancer Institute, Emory University School of Medicine, 1365B Clifton Road, Suite 5100, Room B5101, Atlanta, GA 30322. E-mail: lwchung@emory.edu Received 30 August 2006; Accepted 2 January 2007 DOI 10.1002/pros.20565 Published online 6 March 2007 in Wiley InterScience (www.interscience.wiley.com). ß 2007 Wiley-Liss, Inc.