Sulindac sulfide-induced apoptosis in sinonasal cancer cells

Sulindac metabolism and synergy with tumor necrosis factor-alpha in a drug-inflammation interaction model of idiosyncratic liver injury

Sulindac (SLD) is a nonsteroidal anti-inflammatory drug (NSAID) that has been associated with a greater incidence of idiosyncratic hepatotoxicity in human patients than other NSAIDs. In previous studies, cotreatment of rats with SLD and a modestly inflammatory dose of lipopolysaccharide (LPS) led to liver injury, whereas neither SLD nor LPS alone caused liver damage. In studies presented here, further investigation of this animal model revealed that the concentration of tumor necrosis factor-alpha (TNF-alpha) in plasma was significantly increased by LPS at 1 h, and SLD enhanced this response. Etanercept, a soluble TNF-alpha receptor, reduced SLD/LPS-induced liver injury, suggesting a role for TNF-alpha. SLD metabolites in plasma and liver were determined by LC/MS/MS. Cotreatment with LPS did not increase the concentrations of SLD or its metabolites, excluding the possibility that LPS contributed to liver injury through enhanced exposure to SLD or its metabolites. The cytotoxicities of SLD and its sulfide and sulfone metabolites were compared in primary rat hepatocytes and HepG2 cells; SLD sulfide was more toxic in both types of cells than SLD or SLD sulfone. TNF-alpha augmented the cytotoxicity of SLD sulfide in primary hepatocytes and HepG2 cells. These results suggest that TNF-alpha can enhance SLD sulfide-induced hepatotoxicity, thereby contributing to liver injury in SLD/LPS-cotreated rats.

Cyclooxygenase inhibitors induce apoptosis in sinonasal cancer cells by increased expression of nonsteroidal anti-inflammatory drug-activated gene

Nonsteroidal anti-inflammatory drug-activated gene-1 (NAG-1) has recently been shown to be induced by nonsteroidal anti-inflammatory drugs (NSAIDs) and to have proapoptotic and antitumorigenic activities. Although sulindac sulfide induced apoptosis in sinonasal cancer cells, the relationship between NAG-1 and NSAIDs has not been determined. In this study, we investigated the induction of apoptosis in sinonasal cancer cells treated by various NSAIDs and the role of NAG-1 expression in this induction. The effect of NSAIDs on normal human nasal epithelial (NHNE) cells was also examined to evaluate their safety on normal cells. Finally, the in vivo anti-tumorigenic activity of NSAIDs in mice was investigated. In AMC-HN5 human sinonasal carcinoma cells, indomethacin was the most potent NAG-1 inducer and caused NAG-1 expression in a time- and dose-dependent manner. The induction of NAG-1 expression preceded the induction of apoptosis. Conditioned medium from NAG-1-overexpressing Drosophila cells inhibited proliferation of sinonasal cancer cells and induced apoptosis. In addition, in NAG-1 small interfering RNA-transfected cells, apoptosis induced by indomethacin was suppressed. In contrast, NAG-1 expression and apoptosis were not induced by NSAIDs or conditioned medium in NHNE cells. Furthermore, indomethacin induced a dose-dependent in vivo increase in the expression of NAG-1 mRNA in the mice tumors and the volume of xenograft tumors of AMC-HN5 cells in indomethacin-treated nude mice was reduced compared to that in control mice. In conclusion, indomethacin exerts proapoptotic and antitumorigenic effects in sinonasal cancer cells through the induction of NAG-1 and can be considered a safe and effective chemopreventive agent against sinonasal cancer.