runt相关转录因子3及其甲基化在人胃癌细胞中的表达及调节因素的初步研究  

Preliminary study of expression and modulating factors of runt-related transcription factor 3 and their methylation in human gastric cancer cell lines

作　　者：彭春艳[1] 陈世耀[1] 刘天舒[1] 

机构地区：[1]上海复旦大学中山医院消化科,200032

出　　处：《中华消化杂志》2007年第4期247-250,共4页Chinese Journal of Digestion

基　　金：复旦大学青年基金资助

摘　　要：目的检测不同分化程度胃痛细胞株runt相关转录因子3(RUNX3)基因及其甲基化表达.观察RUNX3 mRNA再表达对胃癌细胞株生物学特性的影响。方法5-氮杂脱氧胞苷(5-AZA-dC)化学处理法和甲基化敏感性聚合酶链反砬(MSP法)检测胃癌细胞RUNX3基因的甲基化状态;采用四甲基偶氮唑盐(MTT)实验检测5氟尿嘧啶(5-FU)对5-AZA-dC处理前、后细胞株的生长抑制率,流式细胞术检测转化生长因子β1(TGF-β1)诱导凋亡的作用。结果①RUNX3在人胃癌细胞SGC7901、MKN45、BGC823中表达.而在MKN28中表达沉默,DNA异常甲基化仪存在于MKN28细胞;②5-AZA-dC处理后,MKN28细胞生长速度显著慢于未处理组,不同浓度5-FU对5-AZA-dC处理后MKN28的生长抑制率显著高于未处理组(P<0.05);③TGF-β1诱导5 AZA-dC处理前后MKN28细胞的早期凋亡具有时效性(P<0.05).两者联用具有协同凋亡作用(P<0.05)。结论DNA异常甲基化是MKN28细胞RUNX3表达沉默的重要机制;RUNX3甲基化可被去甲基化剂5-AZA-dC有效逆转;RUNX3 mRNA的再表达可增强MKN28细胞对5-FU的敏感性和对TGF-β1诱导细胞凋亡的能力。Objective To examine the expression of runt-related transcription factor 3 （RUNX3） mRNA and its methylation in the different stages of differentiated gastric cancer cell lines, and to investigate the effect of reactivation of RUNX3 mRNA on biological characteristics of gastric cancer cells. Methods RUNX3 methylation was detected with chemical genomic screening by 5-aza-2＇-deoxycytidine （5-AZA-dC） and methylation sensitive polymerase chain reaction （MSP）. RUNX3-hypermethylated gastric cancer cell lines were treated with 5-AZA-dC for demethylation. The effect of 5-FU on cell growth rate before and after 5-AZA-dC treatment was evaluated by methylthiazolyldipheny tetrazolium bromide （MTT） method. Transforming growth factor （TGF）-β1-induced apoptosis was analyzed by flow cytometry. Results O RUNX3 mRNA was expressed in three human gastric cancer cell lines （SGC7901, MKN45, BGC823）. RUNX3 was silenced by the promotor hypermethylator in MKN28 cell line with the promoter hypermethylation. O Cell proliferation was reduced in MKN28 cells after the treatment of 5-AZA-dC. Different concentrations of 5-FU had significantly higher inhibition of growth in MKN28 cells after 5-AZA-dC treatment compared to those without 5-AZA-dC treatment （P 〈 0.05）. QTGF-β1 induced early apoptosis of MKN28 cells with or without 5-AZA-dC treatment was time-dependent. TGF- β1 and 5-AZA-dC had a synergistic apoptotic effect. Conclusions Aberrant DNA hypermethylation is the crucial mechanism of RUNX3 silencing in MKN28 cells. RUNX3 hypermethylation can be effectively reversed with de-methylating agent 5-AZA-dC. The re-expression of RUNX3 in MKN28 enhances the cytotoxicity of chemotherapy 5-FU and the sensitivity to TGF-β1 induced apoptosis.

关 键 词：胃肿瘤 DNA甲基化 基因 RUNX3 转化生长因子Β 

分 类 号：R735.2[医药卫生—肿瘤]