新长非编码RNA-IBCI在调控乳腺癌细胞侵袭转移中的作用和机制研究

Long non-coding RNAs (lncRNAs) regulate gene expression at epigenetic, transcriptional and post-transcriptional levels, and have been proposed to be key regulators of diverse biological process. Dysregulation of lncRNAs is often associated with tumor progression. In this project, firstly, we found that integrin-interacting protein Kindlin-2 can regulate the expression of a completely uncharacterized lncRNA-IBCI. And the regulation of Kindlin-2 on lncRNA-IBCI is mediated by histone methyltransferase EZH2, suggesting histone modification H3K27me3 may be involved in the expression regulation of lncRNA-IBCI. Next, biotin-labeled RNA pull-down assay combined mass spectrometry analysis was used to look for the lncRNA-IBCI-interacting proteins. Result showed that Vigilin is one of lncRNA-IBCI-interacting proteins. As Vigilin could bind to 3’UTR of c-fms mRNA and inhibit its expression, we detected the regulation of lncRNA-IBCI on c-fms and found c-fms may be a potential target gene of lncRNA-IBCI. More importantly, overexpression of lncRNA-IBCI led to the inhibition of breast cancer cell invasion and migration. Levels of lncRNA-IBCI expression are higher in normal breast tissue as compared with breast cancer tissue, suggesting that lncRNA-IBCI may play a suppressing role in tumor progression. In this project, we will establish the cascade of Kindlin-2—EZH2—lncRNA-IBCI—c-fms, and explore its role in breast cancer cell invasion and migration. In a word, this study will indicate the regulation mechanism of lncRNA-IBCI expression and unravel the biological function of lncRNA-IBCI.

长链非编码RNA（lncRNAs）在生命活动中具有重要的调节功能，其表达紊乱与肿瘤的发生发展密切相关。我们前期发现，整合素相互作用蛋白Kindlin-2通过组蛋白甲基转移酶EZH2调控一个功能完全未知的长非编码RNA-IBCI的表达。进一步发现，lncRNA-IBCI与RNA结合蛋白Vigilin相互作用，影响Vigilin靶基因c-fms的表达。在功能上，lncRNA-IBCI的过表达抑制乳腺癌细胞的迁移和侵袭；在与乳腺癌的相关性上，lncRNA-IBCI在正常乳腺组织中的表达水平高于乳腺癌组织，提示lncRNA-IBCI可能与乳腺癌的发生发展相关。本申请拟建立Kindlin-2—EZH2—lncRNA-IBCI—c-fms 级联反应，揭示该级联反应的生物学功能并阐明其在调控乳腺癌细胞迁移、侵袭和转移中的重要作用以及在乳腺癌病人中的临床意义。

长链非编码RNA（lncRNAs）在生命活动中具有重要的调节功能，其表达紊乱与肿瘤的发生发展密切相关。我们发现组蛋白甲基转移酶EZH2调控一个功能完全未知的长非编码RNA-IBCI(又称PAS1)的表达。进一步发现，lncRNA-PAS1直接结合到核糖体DNA上，并且招募组蛋白甲基转移酶SUV39H1，导致核糖体DNA的启动子区发生H3K9三甲基化修饰，从而导致核糖体DNA的转录抑制。LncRNA-PAS1的敲减导致核糖体生成的异常激活，并且导致核糖体DNA不稳定性增强，这些都将促进肿瘤细胞的增殖和转移。此外，我们发现负责与SUV39H1结合的PAS1-30nt-RNA能够有效地抑制小鼠乳腺癌的生长和肺转移，揭示PAS1-30nt-RNA很有可能作为治疗乳腺癌的小分子药物发挥作用。这项研究证明 EZH2–lncRNA-PAS1–核糖体级联反应在调节乳腺肿瘤的生长和转移过程中发挥重要作用。 .此外，我们发现整合素相互作用蛋白Kindlin-2乳腺上皮特异性过表达的小鼠中，Kindlin-2与DNA甲基转移酶形成复合物共同抑制上皮标记物E-cadherin的表达，从而促进乳腺肿瘤的发生。在Kindlin-2心脏特异性敲除的老鼠中发现Kindlin-2与组蛋白甲基转移酶SUV39H1形成复合物共同抑制转录因子GATA4的表达,从而保护心脏避免心肌肥厚的发生。