Expression and roles of microRNAs in ovarian tumorigenesis

利用Exiqon microRNA微阵列，我们已经鉴定了几个在人卵巢癌组织和细胞系中异常表达的miRNAs。在卵巢癌中，miR-221是一种高度升高的miRNA，而miR-21和let-7家族的几个成员被发现表达下调。公共数据库被用来揭示高度差异表达的miRNAs的潜在靶点。为了实验鉴定差异表达的miRNAs可能影响其稳定性的转录本，我们将前体miRNAs导入人癌细胞系，并使用寡核苷酸芯片检测其mRNA水平的变化。被miRNA过表达改变最显著的转录本包含相应miRNAs的结合位点。有趣的是，预测目标和实验目标之间几乎没有重叠，或者使用不同细胞系获得的实验目标之间几乎没有重叠，这突显了miRNA目标选择的复杂性。我们目前正在研究这些miRNAs的靶点，以阐明它们在卵巢癌中的作用。这项工作包括通过RT-PCR在细胞系和组织中验证靶标，以及这些靶标在卵巢细胞中的表达，以从功能上测试它们的功能。

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.