Effects of NS398, an inhibitor of cyclooxygenase 2, on the growth and apoptosis of human squamous cell carcinoma cell line Tca8113.

Objective To study the effect of NS398, an inhibitor of cyclooxygenase 2 (COX2), on the growth and apoptosis of human squamous cell carcinoma cell line Tca8113. Methods Cultured Tca8113 cells were incubated with NS398 (0, 6.25, 12.5, 25, 50, 100 μmol/L) for 24, 48 and 72 hours, respectively. Thereafter, MTT method, flow cytometry and transmission electron microscopy were applied to detect the proliferation, cell cycle and apoptosis of Tca8113 cells, respectively. Results The proliferation of Tca8113 cells was inhibited by NS398 in a dose- and time-dependent manner (both P<0.05). FCM analysis showed the appearance of a typical hypodiploid apoptotic (Sub-G1) peak, an increase in the percentage of cells at G0/G1 phase and a decrease in that at S and G2/M phases in NS398 ( 100 μmol/L) -treated Tca8113 cells. Moreover, the cell proliferation index was significantly downregulated by NS398 of 100 μmol/L from 41.03 to 24.33 (P<0.05). Under an electron microscope, morphological changes characteristic of apoptosis were observed in NS398-treated Tca8113 cells. Conclusion NS398, an inhibitor of COX2, could effectively inhibit the growth of Tca8113 cells in vitro by induction of apoptosis. Key words: Carcinoma, squamous cell;  Cyclooxygenase 2 inhibitors;  Cell cycle;  Tumor cells, cul-tured