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目的:通过体外实验观察DNA甲基化转移酶抑制剂5-氮-2′脱氧胞苷(5-aza-2′deoxycytidine,5-aza-dC)对人肺腺癌细胞增殖、凋亡及相关基因表达的影响,初步探讨其在治疗肺部肿瘤的作用及可能机制。方法:分别以0.5、2.0、10.0μmol/L的5-aza-dC处理人肺腺癌A549细胞,用MTT法测定药物干预72h后的光密度值,计算抑制率,流式细胞仪检测5-aza-dC对肺癌细胞株细胞周期及凋亡的影响,实时定量PCR检测相关基因p21、CyclinD1、Bax和Bcl-2mRNA的表达。结果:5-aza-dC能抑制人肺癌细胞株A549的增殖,且呈浓度依赖性;G0/G1期细胞比例下降,S期及G2/M期细胞比例明显高于对照组,出现G2/M细胞周期阻滞;同时,5-aza-dC能诱导A549细胞凋亡;与对照组比较,各药物干预组p21mRNA表达升高(均P<0.01),而CyclinD1mRNA表达无明显变化(P>0.05);与对照组比较,各药物干预组Bax、Bcl-2mRNA表达均明显降低(均P<0.01),且Bax/Bcl-2增高。结论:5-aza-dC能抑制肺癌细胞株的增殖、引起G2/M细胞周期阻滞,并促进凋亡,其机制可能与p21基因的上调及Bax/Bcl-2比值改变有关。
AIM: To observe the effects of 5-aza-2’deoxycytidine (5-aza-dC), a DNA methyltransferase inhibitor, on proliferation, apoptosis and apoptosis of human lung adenocarcinoma cells in vitro Gene expression, preliminary study of its role in the treatment of lung cancer and possible mechanisms. Methods: Human lung adenocarcinoma A549 cells were treated with 0.5,2.0,10.0μmol / L 5-aza-dC respectively. The optical density of the cells was measured by MTT assay 72h after treatment. The inhibition rate was calculated by flow cytometry. aza-dC on the cell cycle and apoptosis of lung cancer cell lines, the expression of p21, CyclinD1, Bax and Bcl-2mRNA were detected by real-time quantitative PCR. Results: 5-aza-dC could inhibit the proliferation of human lung cancer cell line A549 in a concentration-dependent manner. The proportion of cells in G0 / G1 phase decreased, the proportion of cells in S phase and G2 / M phase was significantly higher than that in control group 5-aza-dC can induce the apoptosis of A549 cells. Compared with the control group, the expression of p21mRNA increased (all P <0.01) and the expression of CyclinD1 mRNA did not change significantly (P> 0.05) ; Compared with the control group, the expression of Bax and Bcl-2mRNA in each drug intervention group were significantly decreased (all P <0.01), and Bax / Bcl-2 increased. Conclusions: 5-aza-dC can inhibit the proliferation of lung cancer cell lines, cause G2 / M cell cycle arrest and promote apoptosis. The mechanism may be related to the up-regulation of p21 gene and the change of Bax / Bcl-2 ratio.