Etodolac, a selective cyclo-oxygenase-2 inhibitor, enhances carboplatin-induced apoptosis of human tongue carcinoma cells by down-regulation of FAP-1 expression.

The human tongue well-differentiated squamous carcinoma cell line, SCC-25, shows Fas-dependent apoptosis by treatment with carboplatin (CBDCA). FADD is markedly up-regulated by CBDCA, resulting in the induction of apoptosis. FAP-1, antiapoptotic tyrosine phosphatase, is expressed in the cytosol and blocks the transduction of the "death signal" from Fas to downstream. In this study, we show that etodolac, a selective cyclo-oxygenase-2 inhibitor, enhanced CBDCA-induced apoptosis of SCC-25, although etodolac alone did not induce the apoptosis. In combination with CBDCA, etodolac significantly decreased FAP-1 expression both at protein and mRNA levels, although etodolac by itself did not inhibit FAP-1 expression. These results indicate that etodolac, when combined with CBDCA, can enhance an action of anticancer drug through the suppression of FAP-1 expression.