The selective cyclooxygenase-2 inhibitor mavacoxib (Trocoxil) exerts anti-tumour effects in vitro independent of cyclooxygenase-2 expression levels

The inducible inflammatory Enzyme cyclooxygenase-2 (COX-2) and its product prostaglandin E2 (PGE₂ ) are prominent tumour promoters, and expression of COX-2 is elevated in a number of tumours of both humans and canines. Targeting COX-2 in Cancer is an attractive option because of readily available non-steroidal anti-inflammatory drugs (NSAIDs), and there is a clear epidemiological link between NSAID use and Cancer risk. In this study, we aim to establish the anti-tumourigenic effects of the selective, long-acting COX-2 Inhibitor mavacoxib. We show here that mavacoxib is cytotoxic to a panel of human and canine osteosarcoma, mammary and bladder carcinoma Cancer cell lines; that it can induce Apoptosis and inhibit the migration of these cells. Interestingly, we establish that mavacoxib can exert these effects independently of elevated COX-2 expression. This study highlights the potential novel use of mavacoxib as a Cancer therapeutic, suggesting that mavacoxib may be an effective anti-cancer agent independent of tumour COX-2 expression.