Anti-Proliferative Effects of Piroxicam and Nimesulide on A431 Human Squamous Carcinoma Cell Line

Background Skin cancer is one of the most common types of cancer worldwide and non-steroidal anti-inflammatory drugs (NSAIDs) have been proposed for prevention and treatment of a variety of cancers. Objectives: In this study we aimed to evaluate the cytotoxic effects of piroxicam (a non-selective cyclooxygenase (COX) inhibitor) and nimesulide (a highly selective COX-2 inhibitor) on A431 human squamous carcinoma cell line. Methods Squamous carcinoma cell line (A431) was cultured in RPMI medium containing 10% FBS and penicillin-streptomycin at 37°C and 5% CO₂. Cells were treated with different concentrations of piroxicam and nimesulide (100 - 1000 µmol/L) for 24, 48 and 72 hours (h). Anti-proliferative effects were determined using MTT colorimetric assay. Results Piroxicam and nimesulide reduced cell viability in a time and concentration dependent manner. The most cytotoxic effect was produced in 72 hours incubation time. The IC₅₀ value of nimesulide was significantly lower than piroxicam in 24 and 72 hours, but not in 48 hours treatment duration. Conclusions This study demonstrates that the administration of a highly selective COX-2 inhibitor could probably be more effective than a non-selective NSAID in reducing cancer cells proliferation and that COX-2 can possibly play an important role in skin cancer development.