PTGS2 and malignant colon neoplasm: To further confirm that the UA-mediated inhibition of cell proliferation is through regulation of COX-2 signaling in colon cancer cells, we pretreated SW480 cells with celecoxib (CB, 10 μM), a COX-2-selective inhibitor, and tested the effect of UA on the celecoxib-mediated inhibition of cell proliferation.