Fascin regulates prostate cancer cell invasion and is associated with metastasis and biochemical failure in prostate cancer.

Purpose: Prostate cancer metastasis to secondary organs is considered an initial event in the development of hormone refractory disease and remains the major cause of death among prostate cancer patients. In this study, we investigated the role of fascin, a cytoskeleton actin–bundling protein involved in the formation of filopodia and cell migration, in prostate cancer progression. Experimental Design: Fascin protein expression was examined by immunohistochemistry in a cohort of 196 patients with localized prostate cancer and across several stages of disease progression, including hormone refractory disease. Cellular changes were also assessed in vitro and in vivo in DU145 prostate cancer cell line using fascin gene silencing. Results: Fascin epithelial expression was significantly up-regulated in localized and hormone refractory prostate cancer compared with benign prostate tissue ( P P = 0.075), signifying more aggressive clinical course, thus supporting a function for fascin in prostate cancer progression. In cellular models, fascin gene silencing using small interfering RNA in the androgen-independent prostate cancer cell line DU145 decreased cell motility and invasiveness while increasing cell adhesive properties. In addition, fascin small interfering RNA–expressing DU145 cells implanted orthotopically in mouse prostate showed significantly decreased growth ( P P Conclusions: Our data show a function of fascin in the regulation of prostate cancer progression and emphasize the importance of fascin as a prognostic marker for aggressive disease and as a potential therapeutic target for advanced androgen independent disease.