三氧化二砷对前列腺癌DU-145细胞RASSF1A基因的去甲基化作用

As_2O_3 demethylates RASSFIA gene in DU145 prostate cancer cells

目的研究三氧化二砷(arsenic trioxide,As2O3)对激素非依赖性前列腺癌DU145细胞的生长抑制作用及对RASSF1A基因去甲基化和蛋白表达的影响。方法应用MTT法检测不同浓度(0.5、1.0、2.0、4.0、6.0、12.0、20.0μmol/L)的As2O3不同作用时间(24、48、72 h)对DU145细胞的生长抑制作用;应用甲基化特异性PCR(MSP)和West-ern blot检测As2O3对DU145细胞RASSF1A基因甲基化状态及蛋白表达的影响。结果 As2 O3可抑制DU145细胞的增殖,在一定范围内随着药物浓度的增高,抑制作用逐渐增强(F=838.089,P<0.05);同一浓度作用时间越长,抑制率越高(F=8.849,P<0.05);且As2O3可使RASSF1A基因甲基化逆转,蛋白重新表达。结论 As2O3可以逆转前列腺癌DU145细胞RASSF1A基因启动子CpG岛的异常甲基化,诱导该抑癌基因的重新表达,抑制前列腺癌DU145细胞的增殖。

Objective To determine the inhibitory effects of arsenic trioxide（As2O3） on the proliferation in hormonal independent prostate cancer DU145 cells,and on demethylation and expression of Ras-assciation domain family 1A（RASSF1A）.Methods MTT assay was used to test the growth of DU145 cells after the treatment of As2O3 at 0.5,1.0,2.0,4.0,6.0,12.0 or 20.0 μmol/L for 24,48 or 72 h.Methylation-specific PCR（MSP） and Western blot analysis were used to detect the methylation status and protein expression of RASSF1A gene in Du145 cells after treatment.Results As2O3 significantly inhibited the proliferation of DU145 cells in a dose-and time-dependent manner（F=838.089,P0.05,F=8.849,P0.05）.As2O3 treatment reversed the methylation status of RASSF1A gene and made the protein re-expression.Conclusion As2O3 reverses abnormal methylation status of promoter CpG island of RASSF1A gene in DU145 prostate cancer cells,induces protein re-expression and inhibits the cells proliferation.