甲基转移酶抑制剂对KG1a细胞系的增殖抑制作用

Inhibitory Effect on Proliferation of KG1a Cell Line by Methyltransferase Inhibitors

为探讨甲基转移酶抑制剂通过干扰DNA甲基化发挥抗白血病作用的可能性，采用甲基转移酶抑制剂5-氮杂-2′-脱氧胞苷（5-Aza-CdR)和细胞分化剂CDAⅡ体外处理因高甲基化致p15基因表达失活的髓系白血病细胞系KG1a，经细胞形态学，甲基化特异性PCR（MSP）技术，^3H标记同位素微量分析法，限制性内切酶，流式细胞术及间接免疫荧光等技术对加药前后培养细胞的生物学特征进行观察分析。结果发现，两种药物对KG1a细胞均有时间和（或）浓度依赖性的增殖抑制作用，5-Aza-CdR和CDAⅡ对细胞分别表现了诱导凋亡和诱导分化的可能以及G2和G0/G1期阻滞，与此同时DNA甲基转移酶活性和基因组DNA甲基化程度下降，p15蛋白表达部分恢复，结论：通过抑制甲基转移酶活性，干扰DNA甲基化以发挥抗白血病作用的途径是可能的，值得进一步探讨。

To explore the possibility of a new therapeutic strategy for leukemia by intervening in the DNA methylation tore-express p!5 suppressor gene.Methylation inhibitors,5-Aza-2'-deoxycytidine (5-Aza-CdR) and cell differentiation agent (CDAfl ) were used to treat myelogenous leukemia cell line KGla in which p!5 gene expression was suppressed due to DNA hypermethylation.The biological characteristics of KGla cells untreated or treated with the agents were investigated and analyzed using morphology,methylation specific-PCR (MSP),3H-labeled microassay technique,restriction endonucleases reaction,flow cytometry and immunofluorescence methods.The results indicated that both agents showed concentration-dependent and time-dependent inhibition of cell proliferation.5-Aza-CdR and CDAfl induced apoptosis and cell differentiation with G; and Go/G] arrest,respectively.Furthermore,DNA methyltransferase activity and level of methylation in genomic DNA were decreased and p!5 protein was re-expressed partially.It is concluded that it is possible to treat leukemia by intervening in the DNA methylation using methyltransferase inhibitors and it is worth to make a thorough study on mechanism of the new strategy.