Extract from Serenoa repens suppresses the invasion activity of human urological cancer cells by inhibiting urokinase-type plasminogen activator

We used three human urological cancer cell lines, PC-3, LNCaP and SKRC-1, t o investigate the effects of the extract from Serenoa repens (Palmae) on tu mor cell invasion. The invasion activity of these cell lines was determined in vitro using a Transwell cell-culture chamber. The invasion activity of PC-3 cells into Matrigel was effectively suppressed by the extract at the c oncentration range of 1-10 mug/ml, while that of LNCaP and SKRC-1 cells was unaffected by the extract. The extract did not affect the viability, adhes ion ability, or motility of the cell lines. uPA is more strongly expressed on the membrane fraction of PC-3 cells than that of LNCaP or SKRC-1 cells. The purified uPA activity is inhibited by the extract from S. repens in a d ose-dependent manner, suggesting that the suppression of PC-3 cell invasion by the extract is based on an inhibition of the uPA activity which is nece ssary for tumor cell invasion. These data suggest that the extract from S. repens specifically inhibits the uPA activity and may therefore be useful f or the therapeutic treatment of prostate cancer.