Regulation of metastasis and epithelial-mesenchymal transition by microRNAs

描述（由申请人提供）：我们的长期目标是了解肿瘤进展和转移的机制，并开发分子靶向治疗的新方法。转移是一个多步骤的过程，其中原发肿瘤细胞扩散到身体的远处并形成继发性肿瘤，是癌症死亡的主要原因，也是最不了解的病理过程之一。转移性疾病的新生物标志物和治疗干预的有用靶点，包括蛋白质、microrna和其他非编码rna，继续受到高度关注。我们和其他人已经证明了促进和抑制转移的microrna的存在。此外，我们提供了概念验证证据，表明靶向促转移microRNA的安塔戈米可以在体内有效地递送到快速生长的肿瘤细胞中，并可以阻止其他高度恶性细胞的转移形成。这些单个microrna在转移进展中的分子机制有待进一步研究。在这个应用中：1)我们将识别和表征促进转移的microrna的功能靶点。结合高通量RNA测序、计算方法、功能实验、机制分析和患者研究，我们将研究一种代表新型转移抑制因子的microRNA靶点。2)我们将研究两种不同的转移调节microrna是如何连接的。我们的初步数据表明，特定的促进转移的microRNA （miR-9）的表达导致初级转录物的下调，而另一种促进转移的microRNA （miR-10b）的成熟形式上调。随后，我们将研究miR-9调控miR-10b生物发生的机制，并确定miR-10b是否需要介导miR-9诱导的转移。3)我们将鉴定和表征新的上皮-间质转化（EMT）调节microrna。通过对经历EMT的细胞进行microRNA表达谱分析，我们最近确定了EMT的一个microRNA特征，并发现该特征中的两个microRNA作为EMT诱导剂起作用。我们将确定这两个microrna诱导EMT的机制，以及它们是否调节肿瘤转移和干细胞特性。从这些研究中获得的知识将从根本上推进我们目前对microrna及其靶点如何调节转移和EMT的理解，并可能具有重要的临床意义。

DESCRIPTION (provided by applicant): Our long-term goal is to understand mechanisms of tumor progression and metastasis and to develop new approaches for molecularly targeted therapeutics. Metastasis, a multi-step process in which primary tumor cells disseminate to distant sites of the body and form secondary tumors, is the leading cause of cancer deaths and remains one of the most poorly understood pathological processes. New biomarkers of metastatic diseases and useful targets for therapeutic intervention, including proteins, microRNAs, and other non-coding RNAs, continue to be highly sought. We and others have demonstrated the existence of metastasis-promoting and metastasis-suppressing microRNAs. Moreover, we provided proof-of-concept evidence that antagomirs targeting a pro-metastatic microRNA can be efficiently delivered to fast growing tumor cells in vivo and can block metastasis formation by otherwise highly malignant cells. The molecular mechanisms by which these individual microRNAs function in metastatic progression warrant further investigation. In this application: 1) we will identify and characterize the functional targets of metastasis-promoting microRNAs. Combining high- throughput RNA sequencing, computational approach, functional experiments, mechanistic analysis, and patient studies, we will investigate a microRNA target that represents a novel suppressor of metastasis. 2) We will study how two distinct metastasis-regulating microRNAs are connected. Our preliminary data demonstrated that expression of a specific metastasis-promoting microRNA (miR-9) leads to downregulation of the primary transcript but upregulation of the mature form of another pro-metastatic microRNA (miR-10b). Subsequently, we will investigate the mechanisms by which miR-9 regulates miR-10b biogenesis and determine whether miR-10b is required for mediating miR-9-induced metastasis. 3) We will identify and characterize new epithelial-mesenchymal transition (EMT)-regulating microRNAs. By conducting microRNA expression profiling analysis of cells that have undergone EMT, we have recently identified a microRNA signature of EMT, and discovered that two microRNAs in this signature function as EMT inducers. We will determine the mechanisms by which these two microRNAs induce EMT and whether they regulate tumor metastasis and stem cell properties. The knowledge gained from these studies will fundamentally advance our current understanding of how microRNAs and their targets regulate metastasis and EMT and may have important clinical implications.