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

项目总结/摘要 microRNA是近年来出现的一种小的非编码RNA，是基因调控的重要因子。 在后生动物和植物中表达。除了在正常发育中发挥重要作用外， 在分化中，一些miRNA已显示出作为致癌基因和肿瘤抑制因子。特别是， 多条证据表明miR-17~92簇包含至少一个致癌miRNA。 该簇的扩增和过表达经常在人B细胞亚群中观察到。 淋巴瘤和大量其他人类癌症中。该项目的目标是调查 该簇及其两个旁系同源物的生物学功能、生理学靶点和致癌特性： miR-106b~25和miR-106a~363。我们建议使用实验室小鼠作为这些的模式生物 我们已经产生了携带条件性和组成性功能丧失等位基因的小鼠， 这三个集群。 这一应用体现在三个具体目标中。目的一：研究miR-17~92在肿瘤细胞中的功能 以及它在哺乳动物发育中的两个旁系同源物。在这个目标中提出的实验将使我们能够 从遗传学角度剖析miR-17~92簇，并将其所代表的6种microRNA赋予特定的生物学功能， 编码。此外，它们将使我们能够确定miR-17~92及其受体之间的功能重叠程度。 两个旁系同源物，miR-106~363和miR-106 b ~25。 目的2：探讨miR-17~92在c-Myc诱导的B细胞凋亡中的作用 淋巴瘤这一特定目标的基本原理是基于c-Myc是一种有效的转录调节因子的观察。 miR-17~92的反式激活因子，以及我们自己的初步研究表明，miR-17~92的急性缺失 导致E-Myc B淋巴瘤细胞增殖的急剧减少。这一目标的最终目标是 确定miR-17~92的药理学拮抗剂在B临床前模型中的治疗潜力 细胞淋巴瘤 目的3是鉴定作为miR-17~92的生理靶点的基因组，并验证miR-17~92的生物学活性。 它们在基于细胞的实验和体内的功能相关性。这些目标将通过结合 计算和实验方法，利用条件敲除等位基因的miR- 17~92是我们最近生成的。 我们提出的工作将增加我们对生物功能和作用机制的理解 这类重要的非编码基因。对人类健康有着更大的意义， 研究miRNAs在人类癌症发展中的作用，可能为新的治疗方法铺平道路。 基于其药理学抑制的方法。

Project Summary/Abstract MicroRNAs are small non-coding RNAs that have recently emerged as important modulators of gene expression in metazoans and in plants. In addition to playing important roles in normal development and differentiation, some miRNAs have been shown to act as oncogenes and tumor suppressors. In particular, several lines of evidence indicate that the miR-17~92 cluster includes at least one oncogenic miRNA. Amplification and overexpression of this cluster are frequently observed in a subset of human B-cell lymphomas and in a significant number of other human cancers. The goal of this project is to investigate the biological functions, the physiological targets and the oncogenic properties of this cluster and its two paralogs: miR-106b~25 and miR-106a~363. We propose to use the laboratory mouse as the model organism for these studies and we have already generated mice carrying conditional and constitutive loss-of-function alleles of these three clusters. This application is articulated in three specific aims. In aim 1 we will investigate the functions of miR-17~92 and its two paralogs in mammalian development. The experiments proposed in this aim will allow us to genetically dissect the miR-17~92 cluster and to assign specific biological functions to the six microRNAs that it encodes. In addition they will allow us to determine the extent of functional overlap between miR-17~92 and its two paralogs, miR-106~363 and miR-106b~25. In aim 2, we will investigate the role of miR-17~92 in tumor maintenance in the context of c-Myc induced B cell lymphomas. The rationale for this specific aim is based on the observation that c-Myc is a potent transcriptional transactivator of miR-17~92 and on our own preliminary studies showing that acute deletion of miR-17~92 leads to a dramatic reduction in the proliferation of E¿-Myc B-lymphoma cells. The ultimate goal of this aim is to determine the therapeutic potential of pharmacological antagonists of miR-17~92 in a preclinical model of B cell lymphomas. The objective of aim 3 is to identify the set of genes that are physiologic targets of miR-17~92 and to validate their functional relevance in cell-based experiments and in vivo. These goals will be achieved by combining a computation and an experimental approached that takes advantage of the conditional knockout allele of miR- 17~92 that we have recently generated. The work we are proposing will increase our understanding of the biological functions and mechanism of action of this important class of non-coding genes. Of even greater relevance for human health, it will provide insights into the role of miRNAs in the development to human cancer and may pave the way for novel therapeutic approaches based on their pharmacological inhibition.