PTGS2 and prostate carcinoma: In prostate cancer cell lines, COX-2 CRAds showed a significant cytocidal effect in COX-2-positive mCRPC cell lines (Du-145 and PC3) while there was no significant effect on LnCap (COX-2-negative prostate cancer cells) and BT474 (COX-2-negative control cells) (Figure 3A).