Investigating the functions of the miR-17~92 family of oncogenic microRNA clusters

摘要 MicroRNAs(MiRNAs)是一种小的非编码RNA，长度约为21个核苷酸，调节基因 通过诱导mRNA失稳和翻译抑制在转录后水平表达 靶向mRNAs。在人类中，已发现2000多个miRNAs，并被认为控制着各种 生物过程、发育和癌症。 本次竞争性更新申请的目的是继续我们对生物功能和 多顺反子miR-17~92 miRNA簇的致癌特性，也称为Oncomir1。MiR- 17~92簇包含6个miRNAs(miR-17、miR-18a、miR-19a、miR-19b、miR-20a和miR-92) 根据序列相似性分为四个不同的亚家族：miR-17(包括miR-17和miR-20a)， MiR-18、miR-19(包括miR-19a和miR-19b)和miR-92a。 在过去的五年里，在NIH/NCI拨款R01 CA149707的支持下，我的团队仔细地执行了 史无前例地，通过产生一个特征性的等位基因来对这个多顺反子簇进行遗传解剖 一系列六个基因工程小鼠品系，每个品系携带选择性靶向缺失的个体 MIR-17~92组分。这一分析导致了几个重要的发现，包括发现 MiR-17在骨骼发育和轴型形成中的因果作用，miR-17胚系突变的鉴定 17~92被认为是一种名为Feingold综合征的人类发育综合征的原因，而这一发现 MiR-19家族的miRNAs在Myc驱动的人类癌症的发病机制中起关键作用。 这些令人兴奋的新发现导致了一系列新的假设，这些假设是这次拨款续期的核心 申请。我们提出了一系列实验，这些实验可以归类为以下具体目标。 第一个目标是研究miR-19参与Myc-1基因表达的分子机制。 推动了肿瘤的发生。我们还将测试最近提出的假设，即miR-92在功能上具有拮抗作用 MIR-19作为肿瘤抑制因子发挥作用。 在第二个目标中，我们将测试一种在体内抑制miR-19的新药物方法，该方法基于最近的一种 开发了一种技术，可以将miRNA拮抗剂靶向输送到酸性肿瘤 微环境。 在第三个目标中，我们将开发一种新的、更有效的方法来实验鉴定mirna-mrna。 直接在活体内相互作用。 成功完成这项拨款申请中所述的实验将极大地促进我们的 特别是对这个重要的miRNA簇的理解，以及对一般miRNA的理解，可以导致新的 抗癌药物即将到来。

ABSTRACT MicroRNAs (miRNAs) are small non-coding RNAs approximately 21 nucleotides in length that regulate gene expression at the post-transcriptional level by inducing mRNA destabilization and translational inhibition of target mRNAs. In humans, more than 2000 miRNAs have been identified and are thought to control a variety of biological processes development and cancer. The goal of this competitive renewal application is to continue our investigation of the biological functions and the oncogenic properties of the polycistronic miR-17~92 miRNA cluster, also known as Oncomir1. The miR- 17~92 cluster contains six miRNAs (miR-17, miR-18a, miR-19a, miR-19b, miR-20a, and miR-92) that can be grouped, based on sequence similarity, in four distinct subfamilies: miR-17 (includes miR-17 and miR-20a), miR-18, miR-19 (includes miR-19a and miR-19b), and miR-92a. During the past five years, supported by the NIH/NCI grant R01 CA149707, my group has performed a careful, and unprecedented, genetic dissection of this polycistronic cluster by generating an characterizing an allelic series of six genetically engineered mouse strains, each carrying selective targeted deletion of individual components of miR-17~92. This analysis, has lead to several important findings, including the discovery of causal role for miR-17 in skeletogenesis and axial patterning, the identification of germline mutations of miR- 17~92 as the cause of a human developmental syndrome known as Feingold Syndrome, and the discovery that the miR-19 family of miRNAs plays a key role in the pathogenesis of Myc-driven human cancers. These exciting new findings have lead to a series of novel hypotheses that are at the core of this grant renewal application. We propose a series of experiments that can be grouped into the following specific aims. The first aim has the goal of investigating the molecular mechanisms through which miR-19 contributes to Myc- driven tumorigenesis. We will also test the recently proposed hypothesis that miR-92 functionally antagonizes miR-19 by acting as a tumor suppressor. In the second aim, we will test a novel pharmacologic approach to inhibit miR-19 in vivo based on a recently developed technology that allows targeted delivery of miRNA antagonists to the acidic tumor microenvironment. In the third aim, we will develop a novel and more efficient method to experimentally identify miRNA-mRNA interactions directly in vivo. Successful completion of the experiments described in this grant application would greatly advance our understanding of this important miRNA cluster in particular, and of miRNAs in general, and could lead to novel anticancer approaches.