肿瘤细胞中p27基因转录后调控机制并不完全清楚。课题组利用生物信息学方法筛选p27基因3'-非编码序列(3'-UTR)中可能结合的microRNA分子，试验初步证实miRNA-150能够靶向p27基因，并介导其功能改变。为进一步阐明miRNA-150在p27基因转录后调控的作用机制，本课题拟运用荧光素酶报告基因试验、位点突变、荧光实时定量RT-PCR、原位杂交、基因共转染等实验技术，深入研究miRNA-150靶向调控p27基因的确切机制以及对乳腺癌细胞生物学特性的影响。以上研究为进一步阐明肿瘤细胞中p27基因功能的分子调控机制提供实验依据，并为逆转乳腺癌细胞生物学特性提供潜在干预靶点。

Although p27Kip1(p27) is characterized as a tumor suppressor, inactivating point mutations with loss of heterozygosity are rarely observed in human cancer. Therefore, the low levels of p27 protein observed in many aggressive types of cancer are likely to be mediated by other mechanisms. The abundance of p27 protein is largely controlled through a variety of post-transcriptional regulatory mechanisms. MicroRNAs (miRNAs) are a class of small non-coding RNAs that function to control gene expression through association with the 3'-UnTranslated Region (3'-UTR) of protein coding genes and subsequent induction of translation inhibition. As p27Kip1 is mostly controlled at the post-transcriptional level and miRNAs are potent regulators of gene expression, we hypothesized a role for miRNAs in the contribution of cancer progression through the suppression of p27 expression. However, the exact mechanism of post-transcriptional regulation of p27 is still unclear. Here, we used bioinformatics tools to predict and identify the potential miRNAs binding sites located at the 3'-UTR of p27, a cell cycle inhibitor and tumor suppressor. Our previous results indicated that miR-150 act as a potent regulators of p27. Using miRNA inhibitors, we demonstrate that certain cancer cell lines require high activity of miR-150 to maintain low p27 levels and continuous proliferation. To verify and quantify the effect of miR-150 on p27 post-transcriptional regulation, we subcloned the p27-3′UTR downstream of luciferase. Analysis of transiently transfected cells revealed that the miR-150 expressing vector significantly suppressed p27-3'UTR activity. To further substantiate the specificity of p27-3'UTR-mediated suppression by miR-150. We concluded that miR-150 is a potential regulator of the 3'UTR of p27. Further, using luciferase reporter assays, we have mutated and deleted these predicted sites in order to examine their requirement for miR-150 function to completely refractory to the miR-150 suppressive effect. Flow cytometry,RT-PCR and cell cycle profile analysis to verify miR-150 as potent suppressors of p27 expression. Current study will suggest that it might be possible to use antagomiR-150 as a target of cancer therapy.