我们前期研究发现，PinX1作为潜在抑癌基因，在大多数乳腺癌中明显降低，但其mRNA表达水平在不同标本间差异较大。调控乳腺癌MCF-7细胞的PinX1表达水平，可引起LncRNA表达谱改变，提示可能存在LncRNA与PinX1的互作，并通过转录后水平及蛋白水平等调控作用，影响其分子功能的实现。本项目拟采用全转录组Solexa测序技术，筛选出PinX1低表达与高表达乳腺癌标本的差异LncRNA，对其重注释，预测靶基因、转录因子结合位点，与差异mRNA共表达分析筛选出关键节点LncRNA，5'及3'RACE扩增确认，定量PCR验证其表达水平， ChIRP及RNA pull-down验证其与PinX1及下游靶分子的互作，进而构建乳腺癌MCF-7细胞的LncRNA过表达及敲减模型，体内外实验研究其对肿瘤细胞增殖的影响，为确认PinX1分子功能，探讨乳腺癌发生的非编码RNA调控机制提供新的理论依据。

Our previous study found that, as a potential tumor suppressor gene, although PinX1 decreased in the majority of breast cancer specimens, the mRNA expression level of PinX1 varied greatly in different samples. Furthermore, LncRNA expression profile changes could be induced after we regulated the expression level of PinX1 in MCF-7 breast cancer cell line, which suggesting some interaction may exist between LncRNAs and PinX1, and the LncRNAs may affect the molecular function of PinX1 through after transcription level and protein level regulation. This project intends to screen out the differentially expressed LncRNAs between low and high expressed PinX1 breast cancer specimens through the whole transcriptome library construction and Solexa sequencing technology. The differentially expressed LncRNAs screened out are going to be annotated, predicted for target genes and transcription factor binding sites. The differentially expressed LncRNAs and mRNAs will then be applied for a co-expression analysis, a co-expression network is going to be constructed and the key node LncRNAs of the network will be confirmed by the 5'and 3'RACE amplification. Quantitative PCR will be applied to verify the expression level of the LncRNAs. ChIRP and RNA pull-down are going to be used to verify the interaction of the LncRNAs with PinX1 and other target moleculars. Furthermore, the LncRNAs screened out will be overexpressed or knocked down in breast cancer cell MCF-7 to study their regulation on the tumor cell proliferation. Thus to confirm the molecular function of PinX1, as well as providing new theoretical basis for the regulation of tumorigenesis of breast cancer by the non-coding RNAs.