NS-398对肝癌细胞HepG2增殖和凋亡的影响

目的:探讨选择性环氧合酶II(COX-2)抑制剂NS-398对人肝癌细胞HepG2增殖和凋亡的影响。方法: 应用MTT法研究不同浓度NS-398对HepG2细胞增殖的影响,DNA梯状电泳(DNA ladder)检测凋亡的发生,流式细胞仪检测细胞周期的改变及凋亡百分率的变化,竞争性RT-PCR检测环氧合酶II COX-2 mRNA及抑凋亡基因bcl-2 mRNA表达的改变。结果: NS-398呈剂量依赖性抑制HepG2细胞增殖,并诱导其凋亡,细胞周期分析表明随着浓度增大S期细胞明显减少,有G₀/G₁期细胞累积现象,并伴有Bcl-2 mRNA表达的下调,而对COX-2 mRNA表达改变无明显影响,且COX-2表达改变与NS-398引起的HepG2细胞的增殖和凋亡均无相关性(相关系数分别为:r=0.056,P>0.05和r=0.119,P>0.05)。结论: NS-398能明显抑制HepG2细胞增殖并诱导其凋亡,与细胞G₀/G₁期阻滞以及bcl-2基因表达下调有关,而非依赖于抑制COX-2基因的表达。

Effects of NS - 398 on the proliferation and apoptosis of HepG2 cells

AIM: To evaluate the effects of NS-398, a cyclooxygenase-2(COX-2) inhibitor, on the proliferation and apoptosis in HepG2 cells. METHODS: The effects of NS-398 on the proliferation of HepG2 cells was evaluated by MTT. DNA fragmentation gel analysis was used to analyze the apoptotic cells; DNA ploidy and apoptotic cell percentage were examined by flow cytometry. Furthermore, the expression of COX-2 and Bcl-2 mRNA was identified by competitive RT-PCR. RESULTS: NS-398 inhibited cell proliferation and induced apoptosis in HepG2 in a concentration-dependent manner. DNA ploidy analysis showed that S phase cells were significantly decreased with NS-398 concentration increasing. The quiescent G_0/G_1 phase was accumulated with decreasing of Bcl-2 mRNA. Whereas NS-398 had no effect on the expression of COX-2 mRNA, no correlations were found between COX-2 mRNA and the HepG2 cell proliferation and apoptosis induced by NS-398 (r=0.056 and r=0.119, respectively). CONCLUSION: NS-398 significantly inhibits the proliferation and induces apoptosis in HepG2. Mechanisms may be involved in accumulation of quiescent G_0/G_1 phase and decrease in Bcl-2 mRNA expression, but independent to COX-2 mRNA expression.