微小RNA let-7基因表达在膀胱癌生物学行为中的作用

Expression of microRNA let-7 in bladder cancer

目的 探讨膀胱癌组织中微小RNA（miRNA）表达在膀胱癌发生发展中的作用。方法Trizol法抽提9例膀胱癌患者癌组织及癌旁正常膀胱组织标本总RNA，分离与富集miRNA，随机选取2组miRNA标本与miRNA表达谱芯片杂交，采用LuxScan3．0和SAM2．1软件对芯片结果进行图像数据分析。在差异性表达的miRNA中筛选出感兴趣的let7基因，采用印迹杂交技术对9组miRNA标本中let-7基因进行验证。结果膀胱癌组织和正常膀胱组织标本中差异性表达有显著性意义的miRNA71个，其中表达上调33个，表达下调38个；差异性表达有极显著性意义的miRNA（上调或下调≥4倍）26个，其中显著上调12个，显著下调14个。let-7基因验证结果与芯片表达结果一致，癌组织let-7基因表达吸光度值为479．6±228．2，正常膀胱组织为694．6±152．9，组间差异有统计学意义（P〈0．05）。结论膀胱癌组织和正常膀胱组织中存在差异表达的miRNA，let-7基因在膀胱癌的发生中可能起着抑癌基因的作用。

Objective To detect the differentially expressed microRNAs （miRNAs） in bladder cancer tissue and normal bladder tissue. Methods Total RNA was extracted from bladder cancer tissue and normal bladder tissue by Trizol, and then miRNAs were isolated and enriched from the total RNA. Mammalian miRNA mieroarrays were used to analyze the differentially expressed miRNAs between the bladder cancer tissue and normal tissue. Data analysis was performed by software of LuxScan3.0 and SAM version 2. 1. Choose let-7 gene which was interesting to us, and validation of mi- croarray results was carried out by northern blotting. Results Compared with normal bladder tissues, there were 71 differentially expressed miRNAs in bladder cancer tissue, of which there were 38 down-regulated ones and 33 up-regulated ones. Among these miRNAs, 26 miRNAs were the most significant with 12 up regulated and 14 down-regulated. The expression of let 7 gene in bladder cancer was down-regulated to normal bladder tissue by northern blotting, which was in agreement with the results of the miRNA microarrays. Conclusion There are differentially expressed miRNAs between bladder cancer tissue and normal bladder tissue, and let 7 gene is probably as a tumor suppressor in bladder cancer.