Objective To investigate the effect of NS-398, a selected cyclooxygenase-2 (COX-2) inhibitor and licofelone, a dual COX-2/5-lipoxygenase (5-LOX) inhibitor on the proliferation of TE-1, an esophageal squamous cell carcinoma (ESCC) cell line, and explore the potential limitation of sole COX-2 inhibition on the negative regulation of ESCC cell proliferation. Methods TE-1 cells were divided into drug treatment group, DMSO control group and blank control group. Cells were treated by licofelone or NS-398 in 4 concentrations, including 25 μ mol/L, 50 μmol/L, 75 μmol/L and 100 μmol/L. Cell proliferation was assessed by Cell Counting Kit-8 assay. The expression of COX-2 and 5LOX were determined by both RT-PCR (mRNA) and Western blot (protein), respectively. The concentrations of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) were measured by ELISA. Flow cytometer was used for the cell cycle measurement. Results Cell proliferation inhibition was found in both time and concentration-dependent manners in licofelone treated TE-1 cells, but not in those treated by NS-398. Time and concentration-dependent inhibition of COX-2 mRNA, protein and PGE2 expression were found in TE-1 cells treated with either licofelone or NS-398, while downregulation of 5-LOX mRNA, protein and LTB4 expression were found only in cells treated with licofelone. The level of LTB4 showed an upregulation tendency in cells treated with NS-398, but a significant difference was found only under the coneentration of 100 μmol/L. After 24 h treatment with 100 μmol/L of licofelone and 50 μmol/L of NS-398, the percentages of TE-1 cells in G0/G1-phase were 67.1％ and 63.8％ , respectively, which were significantly higer than those in control group (P ＜0.05). Conclusion Selected COX-2 inhibitor alone may induce ESCC cell proliferation in several specific concentrations, which may be due to the activation of 5-LOX shunt. A dual COX-2/5-LOX inhibitor should be more effective for the inhibition of esophageal squamous cell carcinoma proliferation.%目的 比较选择性环氧合酶-2 (COX-2) 抑制剂与COX-2/5-脂氧合酶 (5-LOX) 双酶抑制剂对食管鳞状细胞癌(ESCC)细胞增殖的影响,探讨单一抑制COX-2对抑制ESCC细胞增殖可能存在的局限性.方法 COX-2/5-LOX双抑制剂licofelone和选择性COX-2抑制剂NS-398分别作用于ESCC细胞株TE-1,设药物处理组、溶媒(DMSO)对照及空白对照组.两种药物分别以25 μmol/L、50 μmol/L、75 μmol/L和100 μmol/L 浓度作用24 h及48 h.四唑单钠盐 (CCK-8)法检测细胞增殖;RT-PCR和Western blot检测mRNA及蛋白表达;ELISA法检测PGE2和LTB4含量;流式细胞术检测细胞周期.结果 TE-1细胞的浓度及时间依赖性增殖抑制只出现于licofelone处理组.licofelone及NS-398对COX-2 mRNA、蛋白及下游产物PGE2表达均有时间、浓度依赖性抑制作用(P<0.05),但仅licofelone处理组出现5-LOX mRNA、蛋白及下游产物LTB4的时间、浓度依赖性表达抑制.100 μmol/L licofelone及50 μmol/L NS-398作用24 h后TE-1细胞分别有67.1%、63.8%处于G0/G1期,显著高于对照组 (P<0.05).结论 单一抑制COX-2并不能稳定抑制TE-1细胞的增殖.较高浓度NS-398可增加5-LOX分流,减弱COX-2抑制对细胞增殖的负性影响.
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