Synergistic Effect by Combination of Meloxicam, a Cox-2 Inhibitor, and Cytotoxic Agents on Human Osteosarcoma Cell Line, Mg-63

Introduction Numerous studies have demonstrated the involvement of cyclooxygenase-2 (COX-2) in carcinogenesis of many types of carcinoma. Osteosarcoma, one of the most common primary malignant bone tumor, is also reported to express COX-2 constitutively (1). COX-2 is an inducible enzyme that catalyzes the synthesis of prostaglandins (PGs), and among them, PGE2 can enhance tumor growth and metastasis by stimulating angiogenesis and invasiveness, and by inhibiting apoptosis. Various types of COX-2 inhibitors have been reported to suppress carcinoma cells, however, there have been few studies that revealed efficacy of COX-2 inhibitors against bone and soft tissue malignant tumors. Chemotherapeutic agents improved prognosis of osteosarcoma patients, however, still not a few patients of osteosarcoma result in lung metastasis after chemotherapy. New therapeautic strategies should be necessary for the patients. Several authors described synergistic effect of combination of COX-2 inhibitor and traditional cytotoxic agents against carcinoma cells (2,3). Meloxicam, a preferential COX-2 inhibitor, has been commercially available as a NSAID. It is demonstrated that meloxicam inhibits the growth of colorectal cancer cells (4), as well as human osteosarcoma cell line, MG-63 (5). In this study, we aimed to assess synergistic effect of combination of meloxicam on cell viability of MG-63 cells.