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

项目摘要/摘要 MicroRNAs是最近作为重要的基因调节器出现的非编码的小RNA 在后生动物和植物中的表达。除了在正常的发展和发展中发挥重要作用 在分化过程中，一些miRNAs已被证明是癌基因和肿瘤抑制因子。特别是， 多条证据表明，miR-17~92簇至少包含一个致癌miRNA。 这个簇的扩增和过度表达经常在人类B细胞的一个亚群中观察到 淋巴瘤和其他相当数量的人类癌症。这个项目的目标是调查 该簇及其两个同源基因的生物学功能、生理靶点和致癌特性： MIR-106b~25和miR-106a~363。我们建议使用实验室小鼠作为这些研究的模式生物。 研究和我们已经产生了携带条件和结构性功能丧失等位基因的小鼠 这三个星团。 这项申请有三个具体目标。在目标1中，我们将研究miR-17~92的功能 以及它在哺乳动物发育中的两个类似物。在这个目标中提出的实验将使我们能够 从基因上剖析miR-17~92簇，并将特定的生物学功能分配给它所涉及的六个microRNAs 编码。此外，它们还将使我们能够确定miR-17~92与其功能重叠的程度 两个对虾，miR-106~363和miR-106b~25。 在目标2中，我们将在c-Myc诱导的B细胞的背景下，研究miR-17~92在肿瘤维持中的作用 淋巴瘤。这一特定目的的理论基础是基于观察到的c-Myc是一种强有力的转录 MiR-17~92反式激活剂和我们自己的初步研究表明miR-17~92的急性缺失 导致E？-Myc B-淋巴瘤细胞的增殖显著减少。这一目标的最终目标是 在B细胞临床前模型中确定miR-17~92药物拮抗剂的治疗潜力 细胞性淋巴瘤。 目标3的目标是识别作为miR-17~92的生理靶点的一组基因并验证 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 计算和利用miR-条件基因敲除等位基因的实验方法。 17~92是我们最近产生的。 我们提议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。对人类健康有更大的相关性，它将提供洞察力 研究miRNAs在人类癌症发生发展中的作用，并可能为新的治疗方法铺平道路 基于它们的药理抑制的方法。

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.