胃癌中显著下调的miR-433的作用靶点研究

目的为了筛选胃癌中miRNAs的表达标记，验证胃癌相关miRNAs的作用靶点，建立一种新的诊断和治疗胃癌的方法。方法运用基因芯片技术检测3个正常胃组织标本，24个胃癌组织标本，胃癌细胞SGC7901和正常胃黏膜细胞GES-1中328个miRNAs的表达情况。用以上方法检测出在胃癌组织和SGC7901中，miR-433的表达水平显著下调。为了确保结果的准确性，采用实时荧光定量PCR对其进行验证。并用基因克隆和Western印迹方法分析miR-433的作用靶点。结果共有26个miRNAs在胃癌标本（包括24个胃癌组织和SGC7901）中异常表达。其中19个miRNAs下调，7个miRNAs上调。实时荧光定量PCR检测出miR-433在胃癌标本中的表达水平显著下调，该结果和基因芯片检测结果一致。另外，在本实验中发现miR-433与Grb2（growth factor receptor—bound protein 2）的表达呈负相关。结论胃癌相关miRNAs已进行了初步筛选。其中，miR-433可能是胃癌中的标记性miRNAs之一，Grb2是其作用靶点。这为建立新的以miRNAs为基础的诊断和治疗胃癌的方法提供了相关信息。

Targeting of miR-433 is Significantly Down-regulated in Gastric Cancer

Objective To screen the miRNAs specific signature of gastric cancer, validate target miRNAs associated with gastric cancer, establish a novel diagnostic and therapeutic method for gastric cancer. Method Microarray technology was applied to detect 328miRNAs expression profiling of 3 normal gastric tissues, 24 malignant tissues, gastric cancer cell SGC7901 and normal gas- tric cell GES-1. Quantitative Real-time PCR （qRT-PCR） was carried out to validate expression level of miR-433 in gastric cancer tissues and SGC7901 cancer cells. Gene cloning and Western blot were used to analyze targeting action of miR-433. Results Twenty-six miRNAs were found to express differentially in gastric cancer samples, including 24 malignant tissues and SGC7901 cancer cell. Of the 26 miRNA, 19 miRNAs were down-regulated and 7 up-regulated. Particularly, qRT- PCR revealed a significant down-regulation of miR-433 expression level in carcinomas samples, similarly to the result of microarray analysis. In addition, miR-433 showed an inverse correlation with Grb2 （growth factor receptor-bound protein 2） Conclusion A preliminary screening of gastric cancer associated miRNAs has been established, miR-433 is of significance for miRNAs specific signature of gastric cancer. Grb2 is the target of miR-433. These preliminary data have provided a novel miRNA-based approach towards diagnosis and therapy for gastric cancer.