TMPRSS2 Influences Prostate Cancer Metastasis

TMPRSS2 is an androgen-regulated cell surface serine protease expressed predominantly in prostate epithelium. TMPRSS2 is expressed highly in localized high-grade prostate cancers and in the majority of human prostate cancer metastasis. Through the generation of mouse models with a targeted deletion of Tmprss2, we demonstrate that the activity of this protease regulates cancer cell invasion and metastasis to distant organs. By screening combinatorial peptide libraries we identified a spectrum of TMPRSS2 substrates that include pro-hepatocyte growth factor (HGF). HGF activated by TMPRSS2 promoted c-Met receptor tyrosine kinase signaling, and initiated a pro-invasive EMT phenotype. Chemical library screens identified a potent bioavailable TMPRSS2 inhibitor that suppressed prostate cancer metastasis in vivo. Together, these findings provide a mechanistic link between androgen-regulated signaling programs and prostate cancer metastasis that operate via context-dependent interactions with extracellular constituents of the tumor microenvironment. Custom mouse cDNA microarrays were used to measure transcript levels in microdissected anterior prostate tumors from Tmprss2+/+;TRAMP mice, Tmprss2-/-;TRAMP mice or strain-matched benign epithelium. All samples were laser-capture microdissected and total RNA isolated and amplified prior to hybridization against a reference pool of normal adult mouse tissues.