The Effects of Selective Cyclooxygenase-2 Inhibitor and Prostaglandin E2 Receptor Agonists on the Endothelin Axis of Prostate Cancer Cells

Purpose: The enhanced expression of the cyclooxygenase-2 (COX-2), prostaglandin E2 receptor (EPs) and endothelin-1 (ET-1) axis is known to play a significant role in the development and progression of several malignancies. To date, little work has been done to investigate the relationships between the COX-2, EPs and ET-1 axis in prostate cancer (PC) cells. The aim of this study is to investigate the expression of preproET-1 (PPET-1), ET-1 receptor A (ETAR), and endothelin converting enzyme-1 (ECE-1) in the PC cell lines and to evaluate the effects of COX-2 and EPs on the expression of PPET-1, ETAR, and ECE-1. Materials and Methods: Two PC cell lines, PC-3 and DU-145 cells were used for this study. By performing reverse transcription polymerase chain reaction (RT-PCR), the mRNA expressions of PPET-1, ETAR and ECE-1 were detected, and then the mRNA expressions of PPET-1, ETAR and ECE-1 were detected after being treating the cells with selective COX-2 inhibitor (NS-398), or EP2 (butaprost) and EP4 (misoprostol), which are both agonist of 10, 10 and 10M. Results: PPET-1, ETAR and ECE-1 mRNA were expressed in both cell lines. After NS-398 treatment, only the PPET-1 mRNA expression was decreased at 4, 8 and 12 hours in the PC-3 cells. EP2 and EP4 agonist induced an increase for the PPET-1, ETAR and ECE-1 mRNA expressions, compared with the NS-398 treated group (control), in the PC-3 cells. Conclusions: ET-1/ETAR and ECE-1, whose expressions are increased by EP2 and EP4, may play key roles in the development and progression of PC via COX-2. A combination treatment with selective inhibitors for COX-2, EPs and ETAR would be novel approach to prostate cancer therapy. (Korean J Urol 2006;47:195-200)