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

摘要 microRNAs（miRNAs）是一类长度约为21个核苷酸的非编码小RNA， 通过诱导mRNA不稳定和翻译抑制， 靶向mRNA。在人类中，已经鉴定了超过2000种miRNA，并且认为它们控制着各种各样的免疫缺陷。 生物过程的发展和癌症。 这项竞争性更新申请的目标是继续我们对生物功能的研究， 多顺反子miR-17~92 miRNA簇（也称为Oncomir 1）的致癌特性。miR- 17~92簇包含6个可被表达的miRNAs（miR-17、miR-18 a、miR-19 a、miR-19 b、miR-20 a和miR-92）， 基于序列相似性，分为四个不同的亚家族：miR-17（包括miR-17和miR-20 a）， miR-18、miR-19（包括miR-19 a和miR-19 b）和miR-92 a。 在过去的五年里，在NIH/NCI资助R 01 CA 149707的支持下，我的小组进行了一项仔细的， 通过产生一个具有特征的等位基因， 一系列六种基因工程小鼠品系，每种都携带选择性靶向缺失的个体， miR-17~92的组分。这一分析导致了几个重要的发现，包括发现 miR-17在骨骼发生和轴向模式中的因果作用，miR-17的种系突变的鉴定， 17~92作为人类发育综合征的原因，称为Feingold综合征， miR-19家族在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引出了一系列新颖的假设，这些假设是此次资助更新的核心 应用程序.我们提出了一系列实验，可以分为以下具体目标。 第一个目标是研究miR-19促进Myc-1表达的分子机制。 驱动的肿瘤发生。我们还将测试最近提出的假设，即miR-92在功能上拮抗 miR-19作为肿瘤抑制因子。 在第二个目标中，我们将根据最近的研究结果，测试一种新的体内抑制miR-19的药理学方法。 开发了一种技术，允许将miRNA拮抗剂靶向递送至酸性肿瘤 微环境 在第三个目标中，我们将开发一种新的和更有效的方法来实验性地鉴定miRNA-mRNA 直接在体内相互作用。 成功完成这项资助申请中描述的实验将大大推进我们的研究。 了解这个重要的miRNA簇，特别是一般的miRNA，并可能导致新的 抗癌方法。

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.