ABSTRACT
<p><b>OBJECTIVE</b>To study the effects of nimesulide, a selective COX-2 inhibitor, on cell viability, telomerase and PKB activities in human gastric cancer cell line SGC7901 and to explore its molecular mechanism of selective growth inhibition.</p><p><b>METHODS</b>MTT assay was used to determine cell viability after incubation for 0, 12, 24, and 48 h in different concentrations (0, 25, 50, 100, 200 micro mol/L) of nimesulide and/or okadaic acid (300 nmol/L). Telomerase and protein kinase B (PKB) activities were detected using TRAP PCR-ELISA and nonradioactive IP-kinase assay.</p><p><b>RESULTS</b>Nimsulide caused a time and dose-dependent reduction of cell numbers of SGC7901. The telomerase and PKB activities were significantly inhibited, and the inhibition of telomerase activity was partly associated with decrease in PKB activity.</p><p><b>CONCLUSION</b>Selective COX-2 inhibitor nimesulide inhibits telomerase activity of gastric cancer cells by partly blocking the activation of protein kinase B. The results suggest an additional signaling pathway underlying the anti-cancer effect of COX-2 inhibitor.</p>