目的探讨5-Aza-dC和TSA对肝细胞癌(hepatocellular carcinoma,HCC)细胞中3-OST-2甲基化水平、基因表达以及对核转录因子UHRF1(ubiquitin-like with PHD and ring finger domains 1,也称为ICBP90/NP95)表达的影响。方法采用甲基化特异性P...目的探讨5-Aza-dC和TSA对肝细胞癌(hepatocellular carcinoma,HCC)细胞中3-OST-2甲基化水平、基因表达以及对核转录因子UHRF1(ubiquitin-like with PHD and ring finger domains 1,也称为ICBP90/NP95)表达的影响。方法采用甲基化特异性PCR(methylation specific PCR,MSP)法检测药物作用前后HCC细胞株中3-OST-2甲基化的状态改变;采用实时荧光定量RT-PCR法检测3-OST-2和UHRF1 mRNA的表达变化;采用细胞爬片免疫组化法检测UHRF1蛋白表达。结果 3-OST-2在HCC细胞株中呈完全甲基化状态,5-Aza-dC或TSA均能部分逆转3-OST-2甲基化,其mRNA表达分别增加2.7倍和4.9倍,两种药物联合处理后,3-OST-2甲基化被完全逆转,其mRNA表达增加9.1倍。5-Aza-dC或TSA均能降低UHRF1 mRNA和蛋白的表达,TSA比5-Aza-dC疗效更好(P<0.01),两种药物联用具有协同作用(P<0.01)。结论启动子甲基化和组蛋白修饰共同导致3-OST-2基因表达降低。5-Aza-dC和TSA单独作用均能部分逆转3-OST-2甲基化,增加其mRNA表达,抑制核蛋白UHRF1表达可能是其中机制之一。展开更多
The present study aimed to evaluate the relationship between mTOR signaling pathway and DNA methylation in cell survival,cell cycle,gene expression and protein level on human gastric cancer cells. Human gastric cancer...The present study aimed to evaluate the relationship between mTOR signaling pathway and DNA methylation in cell survival,cell cycle,gene expression and protein level on human gastric cancer cells. Human gastric cancer cell lines,MKN45 and SGC7901 were treated with 5-aza-dC,rapamycin and/or LY294002.Cell viability was analyzed by MTT.Cell cycle distribution was evaluated by flow cytometry (FCM).The transcription level of PTEN and p27 Kip1 genes was detected by using real-time PCR.Protein expressions were detected by Western blotting.We found that cell viability was moderately reduced when treated with 5-aza-dC alone,but remarkably reduced when mTOR pathway was inhibited together (P<0.01).mTOR inhibition enhances the effects of 5-aza-dC on arresting cell cycle at G2 phase in human gastric cancer cell lines.The expression of PTEN and p27 Kip1 mRNA was remarkably increased in the gastric cancer cells treated with combind drugs(P<0.01).Phosphorylation of Akt,p70S6K and 4E-BP1 were significantly reduced in the cells treated with LY294002 or RAPA(P<0.01),but we failed to find that 5-aza-dC enhance these effects.We suggested that mTOR inhibition could enhance the effects of 5-aza-dC on suppressing cell proliferation and arresting cell cycle in human gastric cancer cell lines, which might be a potential target for tumor therapy.展开更多
文摘目的探讨5-Aza-dC和TSA对肝细胞癌(hepatocellular carcinoma,HCC)细胞中3-OST-2甲基化水平、基因表达以及对核转录因子UHRF1(ubiquitin-like with PHD and ring finger domains 1,也称为ICBP90/NP95)表达的影响。方法采用甲基化特异性PCR(methylation specific PCR,MSP)法检测药物作用前后HCC细胞株中3-OST-2甲基化的状态改变;采用实时荧光定量RT-PCR法检测3-OST-2和UHRF1 mRNA的表达变化;采用细胞爬片免疫组化法检测UHRF1蛋白表达。结果 3-OST-2在HCC细胞株中呈完全甲基化状态,5-Aza-dC或TSA均能部分逆转3-OST-2甲基化,其mRNA表达分别增加2.7倍和4.9倍,两种药物联合处理后,3-OST-2甲基化被完全逆转,其mRNA表达增加9.1倍。5-Aza-dC或TSA均能降低UHRF1 mRNA和蛋白的表达,TSA比5-Aza-dC疗效更好(P<0.01),两种药物联用具有协同作用(P<0.01)。结论启动子甲基化和组蛋白修饰共同导致3-OST-2基因表达降低。5-Aza-dC和TSA单独作用均能部分逆转3-OST-2甲基化,增加其mRNA表达,抑制核蛋白UHRF1表达可能是其中机制之一。
基金grants from the National Natural Science Foundation for DistinguishedYoung Scholars(Grant No.30625034)
文摘The present study aimed to evaluate the relationship between mTOR signaling pathway and DNA methylation in cell survival,cell cycle,gene expression and protein level on human gastric cancer cells. Human gastric cancer cell lines,MKN45 and SGC7901 were treated with 5-aza-dC,rapamycin and/or LY294002.Cell viability was analyzed by MTT.Cell cycle distribution was evaluated by flow cytometry (FCM).The transcription level of PTEN and p27 Kip1 genes was detected by using real-time PCR.Protein expressions were detected by Western blotting.We found that cell viability was moderately reduced when treated with 5-aza-dC alone,but remarkably reduced when mTOR pathway was inhibited together (P<0.01).mTOR inhibition enhances the effects of 5-aza-dC on arresting cell cycle at G2 phase in human gastric cancer cell lines.The expression of PTEN and p27 Kip1 mRNA was remarkably increased in the gastric cancer cells treated with combind drugs(P<0.01).Phosphorylation of Akt,p70S6K and 4E-BP1 were significantly reduced in the cells treated with LY294002 or RAPA(P<0.01),but we failed to find that 5-aza-dC enhance these effects.We suggested that mTOR inhibition could enhance the effects of 5-aza-dC on suppressing cell proliferation and arresting cell cycle in human gastric cancer cell lines, which might be a potential target for tumor therapy.
