微小RNA-223及其标靶基因c-myc在肝癌发病中的作用

目的 探讨微小RNA-223(miR-223)对原癌基因c-myc的调控及其在肝癌发病中的作用.方法 通过实时定量聚合酶链反应和Western blot检测正常肝脏组织、癌旁组织、肝癌组织及肝癌HepG2细胞、胎肝L02细胞中miR-223和c-myc的mRNA和蛋白质表达水平.构建miR-223模拟物(mimics)上调肝癌细胞HepG2中miR-223表达后,实时定量聚合酶链反应和Western blot 检测HepG2细胞中c-myc表达水平的变化.分别用独立样本t检验和单因素方差分析进行两组及多组数据间的比较,P＜0.05为差异有统计学意义.结果 miR-223在正常肝组织、癌旁组织和肝癌组织中的相对表达量分别为0.055±0.015、0.030±0.008和0.020±0.016,肝癌组织低于正常肝组织(t=-0.031,P＜0.05).miR-223在HepG2细胞中的表达较L02细胞下调(0.005±0.003比0.011±0.006,t=12.74,P＜0.01).c-myc mRNA在正常肝组织、癌旁组织和肝癌组织中的相对表达量分别为0.029±0.023、0.136±0.071和0.425±0.026,肝癌组织高于正常肝组织(t=-0.317,P＜0.05);c-myc蛋白在正常肝组织、癌旁组织和肝癌组织中的相对表达量分别为0.137±O.015、0.299±0.033和0.439±0.027,差异有统计学意义(F=103.35,P＜0.01).miR-223 mimics转染HepG2细胞后,c-myc蛋白在空白组、转染组和阴性对照组的相对表达量分别为0.423±0.041、0.116±0.015和0.432±0.034,转染组较其他两组明显降低(F=94.93,P＜0.05).结论 miR-223在肝癌组织中表达下调,丧失其对c-myc表达的抑制而导致c-myc异常高表达可能是肝癌发生的重要机制.

Abstract：

Objective To investigate the regulatory role of microRNA-223 (miR-223) on c-myc and its role in hepatocarcinogenesis.Method miR-223 and c-myc mRNA expressions in normal tissue,paraneoplastic tissue,liver cancer tissue and liver cancer cells were tested with microRNA microarray and quantitative real-time PCR (qRT-PCR).C-myc protein expression was detected by Western blot.MiR-223mimic was transfected into HepG2 cells and the expression changes of c-myc mRNA and protein were tested with qRT-PCR and Western blot respectively.Results MiR-223 was down-regulated by 61.53% and 30.77% respectively in hepatocellular carcinoma and adjacent tissues as compared to normal liver tissues and the expression of miR-223 was also decreased in HepG2 cell as compared to fetal liver cells L02,whereas the expressions of c-myc mRNA and protein increased in paraneoplastic and HCC tissues compared with normal liver tissues.It prompts that the expressions of miR-223 and c-myc are negatively correlated.No obvious difference found among c-myc mRNA expressions after miR-223 mimics transfection.Conclusions The cmyc abnormal high-expression may play a dynamic role in hepatocarcinogenesis due to the miR-223 downregulation.

Role of microRNA-223 and its target gene oncogene c-myc in hepatocellular carcinoma pathogenesis

Objective To investigate the regulatory role of microRNA-223 (miR-223) on c-myc and its role in hepatocarcinogenesis.Method miR-223 and c-myc mRNA expressions in normal tissue,paraneoplastic tissue,liver cancer tissue and liver cancer cells were tested with microRNA microarray and quantitative real-time PCR (qRT-PCR).C-myc protein expression was detected by Western blot.MiR-223mimic was transfected into HepG2 cells and the expression changes of c-myc mRNA and protein were tested with qRT-PCR and Western blot respectively.Results MiR-223 was down-regulated by 61.53% and 30.77% respectively in hepatocellular carcinoma and adjacent tissues as compared to normal liver tissues and the expression of miR-223 was also decreased in HepG2 cell as compared to fetal liver cells L02,whereas the expressions of c-myc mRNA and protein increased in paraneoplastic and HCC tissues compared with normal liver tissues.It prompts that the expressions of miR-223 and c-myc are negatively correlated.No obvious difference found among c-myc mRNA expressions after miR-223 mimics transfection.Conclusions The cmyc abnormal high-expression may play a dynamic role in hepatocarcinogenesis due to the miR-223 downregulation.