Expression and roles of microRNAs in ovarian tumorigenesis

使用Exiqon microRNA微阵列，我们已经鉴定了几个在人类卵巢癌组织和细胞系中异常表达的mirna。miR-221在卵巢癌中是一个高度升高的miRNA，而miR-21和let-7家族的几个成员被发现下调。使用公共数据库来揭示高度差异表达的mirna的潜在靶标。为了实验鉴定其稳定性可能受到差异表达miRNAs影响的转录本，我们将前体miRNAs转染到人类癌细胞中，并使用寡核苷酸微阵列检测mRNA水平的变化。受miRNA过表达影响最显著的转录本包含相应miRNA的结合位点。有趣的是，预测靶点与实验靶点之间，或使用不同细胞系获得的实验靶点之间几乎没有重叠，这突出了miRNA靶点选择的复杂性。我们目前正在研究这些mirna的靶点，以阐明它们在卵巢癌中的作用。这项工作包括在细胞系和组织中通过RT-PCR验证靶点，以及在卵巢细胞中表达这些靶点以功能性测试其功能。

Using the Exiqon microRNA microarrays, we have identified several miRNAs aberrantly expressed in human ovarian cancer tissues and cell lines. miR-221 stands out as a highly elevated miRNA in ovarian cancer, while miR-21 and several members of the let-7 family are found downregulated. Public databases were used to reveal potential targets for the highly differentially expressed miRNAs. In order to experimentally identify transcripts whose stability may be affected by the differentially expressed miRNAs, we transfected precursor miRNAs into human cancer cell lines and used oligonucleotide microarrays to examine changes in the mRNA levels. The transcripts that were most significantly altered by miRNA overexpression contained binding sites for the corresponding miRNAs. Interestingly, there was little overlap between the predicted and the experimental targets, or between experimental targets obtained using different cell lines highlighting the complexity of miRNA target selection. We are currently investigating the targets of these miRNAs in order to clarify their roles in ovarian cancer. This work involves the validation of the targets by RT-PCR in cell lines and tissues, as well as the expression of these targets in ovarian cells to functionally test their functions.