A 5-μM concentration of neither a pan-caspase inhibitor nor the specific caspase 3 inhibitor could protect RA FLSs against celecoxib-induced cell death, whereas cell death induced by TRAIL was significantly reduced by a 5-μM concentration of either pan-caspase inhibitor z-VAD-fmk or caspase 3 inhibitor (Figure 5). Here, CASP3 is linked to rheumatoid arthritis.