肝癌细胞对5-氮杂-2'-脱氧胞苷的敏感性与细胞总DNA甲基化水平无关

目的 比较不同肝癌细胞株对5-氮杂-2'-脱氧胞苷(5-aza-dC)的敏感性,探讨肝癌细胞对5-aza-dC的敏感性是否与细胞总DNA甲基化水平有关.方法 用不同剂量(0.5、5.0、10.0μmol/L)的5-aza-dC处理肝癌细胞株(HepG2、QGY7701和HepG2.2.15细胞)及正常肝细胞株L02,比较不同浓度处理前后的细胞增殖抑制率,比较10 μmol/L 5-aza-dC处理前后的Caspase-3活性及细胞DNA片段化水平(5-溴脱氧尿嘧啶核苷掺入率),比较不同细胞总DNA甲基化水平.组间检测结果比较采用t检验.结果 5-aza-dC对HepG2、QGY7701、HepG2.2.15、L02细胞的半数抑制浓度分别为0.5、0.5、4.5、11.4μmol/L,与HepG2细胞和QGY7701细胞相比,HepG2.2.15绌胞和L02细胞对5-aza-dC不敏感.HepG2和QGY7701细胞中Caspase-3的活性升高较L02和HepG2.2.15细胞明显(P值均＜0.05),QGY7701细胞中5-溴脱氧尿嘧啶核苷掺入率升高较L02细胞明显(P＜0.05).L02、HepG2、QGY7701和HepG 2.2.15细胞的DNA总甲基化水平分别为11.7%±0.9%、10.9%±1.3%、11.7%±1.7%和12.2%±1.0%,差异无统计学意义(P值均＞0.05).结论 细胞对5-aza-dC的敏感性与细胞总DNA甲基化水平无关.

No correlation between the sensitivity to 5-aza-dC and the global DNA methylation level in hepatocelullar carcinoma cells

Objective To compare the sensitivity of different hepatocelullar carcinoma(HCC)cell lines(HepG2,QGY7701,HepG2.2.15)and the normal liver cell line L02 to 5-aza-dC,an DNA methyltransferase inhibitor,and to explore the relationship between global DNA methylation level and the sensitivity to 5-aza-dC.Methods HepG2,QGY7701,HepG2.2.15 and L02 cells were treated with 5-aza-dC at different concentration.cell proliferation was measured by MTT method,cell apoptosis was detected by measuring caspase 3 activity and cellular DNA fragmentation ELISA.Results Compared to HepG2 and QGY7701 cells,HeDG2.2.15 were less sensitive to the treatment of 5-aza-dC;the normal liver cell line L02 was less sensitive to 5-aza-dC than the HCC cell lines.Conclusions The sensitivity to 5-aza-dC of HCC cell lines and normal liver cells is not correlated with the global DNA methylation level.