Effect of selected nonsteroidal anti-inflammatory drugs on the viability of canine osteosarcoma cells of the D-17 line: in vitro studies

Introduction: Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in veterinary medicine. They are used in pain control and in anti-inflammatory and antipyretic therapies. Some NSAIDs, e.g. piroxicam, also have a documented anticancer effect. The objective of this study was to evaluate which of the commonly used NSAIDs (etodolac, flunixin, tolfenamic acid, carprofen, and ketoprofen) are cytotoxic to the D-17 cell line of canine osteosarcoma. Material and Methods: The viability of the cells was evaluated using the MTT assay. Four independent repetitions were performed and the results are given as the average of these values; EC50 values (half maximal effective concentration) were also calculated. Results: The analysis of results showed that carprofen and tolfenamic acid displayed the highest cytotoxicity. Other drugs either did not provide such effects or they were very poor. For carprofen, it was possible to determine an EC50 which fell within the limits of concentrations obtainable in canine serum after the administration of routinely used doses. Conclusion: The results are promising but further studies should be conducted to confirm them, since this study is only preliminary. The possibility of introducing carprofen and tolfenamic acid into the routine treatment of osteosarcoma in dogs should be considered.