Objective:To explore the effects and possible mechanism of recombinant human endothelin-1(ET-1) on cyclooxygenase-2(COX-2) expression in PC3 cells. Methods:PC3 cells were stimulated with ET-1(0.1-1-10-100 nmol/l) for 24 h; then BQ-123(ETAR antagonist,1 μmol/L) and BQ788(ETBR antagonist, 1 μmol/L) were used to treat PC3 cells in combination with ET-1(100 nmol/l) for 24 h. COX-2 expression in the cells was detected by RT-PCR and Western blot assay. Results:The COX-2 expression in the cells was significantly increased after exposove to ET-1(0.1-100 nmol/l) for 24 h. BQ-123 prevented the expression of COX-2(P < 0.05) while BQ-788 did not. Conclusion:ET-1 could induce the up-regulation of COX-2 in PC3 cells. ETAR might be involved during the course. Agents able to specifically interfere with COX-2 and ETAR might lead to effective treatment in the future.