Purpose: The disintegrin metalloprotease ADAM-10 is a multidomain metalloprotease that is potentially significant in tumor progression due to its extracellular matrix-degrading properties. Previously, ADAM-10 mRNA was detected in prostate cancer (PCa) cell lines; however, the presence of ADAM-10 protein and its cellular localization, regulation, and role have yet to be described. We hypothesized that ADAM-10 mRNA and protein may be regulated by growth factors such as 5alpha-dihydrotestosterone, insulin-like growth factor I, and epidermal growth factor, known modulators of PCa cell growth and invasion.
Experimental design: ADAM-10 expression was analyzed by in situ hybridization and immunohistochemistry in prostate tissues obtained from 23 patients with prostate disease. ADAM-10 regulation was assessed using quantitative reverse transcription-PCR and Western blot analysis in the PCa cell line LNCaP.
Results: ADAM-10 expression was localized to the secretory cells of prostate glands, with additional basal cell expression in benign glands. ADAM-10 protein was predominantly membrane bound in benign glands but showed marked nuclear localization in cancer glands. By Western blot, the 100-kDa proform and the 60-kDa active form of ADAM-10 were synergistically up-regulated in LNCaP cells treated with insulin-like growth factor I plus 5alpha-dihydrotestosterone. Epidermal growth factor also up-regulated both ADAM-10 mRNA and protein.
Conclusions: This study describes for the first time the expression, regulation, and cellular localization of ADAM-10 protein in PCa. The regulation and membrane localization of ADAM-10 support our hypothesis that ADAM-10 has a role in extracellular matrix maintenance and cell invasion, although the potential role of nuclear ADAM-10 is not yet known.