尼美舒利对人胃癌细胞株MKN28细胞周期和PTEN、mTOR基因表达的影响

背景：环氧合酶-2（COX-2）抑制剂的肿瘤化学预防作用已被广泛研究，但其作用机制仍未明确。胛EN为一多肿瘤抑制基因，对mTOR信号途径起负调控作用。目的：探讨选择性COX-2抑制剂尼美舒利对人胃癌细胞株MKN28细胞周期和PTEN、mTOR基因表达的影响。方法：以不同浓度尼美舒利于预MKN28细胞．甲基噻唑基四唑（MYr）实验检测细胞活力，流式细胞分析检测细胞周期，实时荧光定量聚合酶链反应（PCR）检测胛EN、mTORmRNA表达。结果：200～600μmol／L尼美舒利作用24～60h对MKN28细胞增殖有明显抑制作用，且作用呈时间-浓度依赖性。200μmol／L和400μmol／L尼美舒利作用48h可使MKN28细胞周期阻滞于G0／G1期和G2，M期。400pmloFL尼美舒利作用36h和48h可显著上调MKN28细胞PTENmRNA表达，作用24h和36h可显著下调mTORmRNA表达。结论：尼美舒利可通过阻滞细胞周期、调控胛EN、mTOR基因表达抑制人胃癌细胞生长。mTOR信号途径与COX-2通路之间可能存在交互作用。

Effects of Nimesulide on Cell Cycle and Expressions of PTEN and mTOR Genes in Human Gastric Cancer Cell Line MKN28

Background： The chemopreventive effects of cyclooxygenase-2 （COX-2） inhibitors on malignant tumors have been studied extensively, however, its mechanism still remain unclear. PTEN is a muhiple tumor suppressor gene that can negatively modulate the roTOR signaling pathway. Aims： To investigate the effects of nimesulide, a selective COX-2 inhibitor, on cell cycle and expressions of PTEN and mTOR genes in human gastric cancer cell line MKN28. Methods： MKN28 cells were treated with nimesulide at different concentrations. The viability of MKN28 cells was determined by methyl thiazolyl tetrazolium （MTT） assay, cell cycle distribution was assessed by flow cytometry, and expressions of PTEN and mTOR mRNA were determined by real-time fluorescent quantitative polymerase chain reaction （PCR）. Results： 200-600μmol/L nimesulide treating for 24-60 hours could inhibit the growth of MKN28 cells in a time- and concentration-dependent manner. Cell cycle of MKN28 cells was arrested at G0/G1 phase and G2/M phase when treated with 200 μmol/L or 400μmol/L nimesulide for 48 hours. 400μmol/L nimesulide could increase the expression of PTEN mRNA after treating for 36 hours and 48 hours, and decrease the expression of mTOR mRNA after treating for 24 hours and 36 hours in MKN28 cells. Conclusions： Nimesulide can inhibit the proliferation of human gastric cancer cells via arrest of cell cycle and modulation of PTEN and mTOR genes expression. An interaction may exist between mTOR signaling pathway and COX-2 pathway.