Induction of urokinase-type plasminogen activator by lipopolysaccharide in PC-3 human prostatic cancer cells

Urokinase-type plasminogen activator (uPA) plays a central role in many aspects of cellular regulation, such as fibrinolysis, cell migration, and metastasis. The uPA induction by inflammatory stimuli such as IL-1, TNFalpha, and lipopolysaccharide (LPS) has been reported in a number of human cells. We examined the effects of LPS on uPA expression in human PC-3 prostatic cancer cells that express uPA in a conditioned medium. LPS increased the uPA accumulation in PC-3 cells, whereas IL-1, IL-6, and TNFalpha did not. Northern blot analysis revealed that the peak induction of uPA mRNA occurred 5 hours after LPS stimulation. A protein synthesis inhibitor, cycloheximide, amplified the LPS-induced uPA mRNA, suggesting that LPS induces uPA by activating the gene expression in which de novo protein synthesis is not necessary.