10-羟基喜树碱对肝癌细胞HepG2 DNA甲基化水平的调节作用研究

Effects of 10-hydroxycamptothecine on the Regulation of DNA Methylation Level in Liver Cancer Cell Hep G2

目的:研究10-羟基喜树碱对肝癌细胞Hep G2的DNA甲基化水平的调节作用。方法:体外培养Hep G2细胞,分为给药组(10-羟基喜树碱25μg/ml)和空白对照组,每组6个小组,每小组5个平行孔,分别于给药后24、48、72 h各组取2个小组,一组用MTT法检测Hep G2细胞的生长抑制率;另一组提取Hep G2细胞的DNA,酸水解后高效液相色谱法检测其甲基化率。结果:10-羟基喜树碱作用24、48、72 h后,Hep G2细胞的生长抑制率分别为(61.6±4.9)%、(85.7±0.7)%、(97.9±0.7)%;给药组Hep G2细胞DNA甲基化率分别为(2.81±0.34)%、(6.67±0.24)%、(6.83±0.24)%,明显高于相应的空白对照组[(1.88±0.13)%、(1.91±0.11)%、(1.98±0.18)%](P<0.05),且与作用时间呈正相关。结论:10-羟基喜树碱在抑制Hep G2细胞的生长的同时提高了细胞DNA的甲基化水平。

OBJECTIVE： To study the effects of 10-hydroxycamptothecine （10-HCPT） on the regulation of DNA methylation level in liver cancer cell HepG2. METHODS： Liver cancer cell HepG2 was cultured in vitro and divided into medication group （10-HCPT 25 μg/ml） and blank control group with 6 subgroups in each group. There were 5 parallel holes in each subgroup. 2 sub- groups were sampled in each group 24, 48 and 72 h after medication. For one subgroup, the growth inhibition rates of HepG2 was detected by using MTT assay; for another subgroup, DNA of HepG2 and the parallel test cell were extracted respectively, and the methylation rate was determined by HPLC after acid hydrolysis. RESULTS： After treated with 10-HCPT for 24, 48 and 72 h, the growth inhibition rates of HepG2 were （61.6 ± 4.9）%, （85.7 ± 0.7）% and （97.9 ± 0.7）%. The DNA methylation rate of medication group were （2.81 ± 0.34）%, （6.67 ± 0.24）% and （6.83 ± 0.24）%, which were significantly higher than those of blank control group [（1.88 ± 0.13% ）, （1.91± 0.11）% and （1.98± 0.18）%] （P〈0.05）, positively associated with treatment time. CONCLUSIONS： 10-HCPT may increase the overall DNA methylation level during inhibiting cancer cell.