Rofecoxib has Different Effects on Chemokine Production in Colorectal Cancer Cells and Tumor Immune Splenocytes

Cyclooxygenase-2 (COX-2) is overexpressed in colon tumors. Its main product is the immunosuppressive prostaglandin PGE2 that aids tumor immune escape. In this study, we analyzed mechanisms of action of the COX-2 inhibitor rofecoxib on the immune response to colorectal cancer in an animal model. The murine colorectal cancer cell line MC26, and splenocytes from BALB/c mice immune to irradiated MC26 cells, were incubated with rofecoxib or PGE2. In MC26 cells, 100 nM rofecoxib caused a complete abrogation of PGE2 production and inhibited cell proliferation. Splenocytes from tumor immune mice showed a 300% (P