Targeting miRNA in brain tumors.

描述（由申请人提供）：微小RNA（miRNAs）是最近发现的一类20-22个核苷酸的小的非编码RNA分子，其已显示在各种生物体中调节靶基因表达。 通过靶向蛋白质编码基因的mRNA进行切割或抑制翻译，miRNA被认为在发育、生长控制、增殖和细胞谱系决定中起关键作用。 然而，这类新的调控RNA影响恶性肿瘤增殖和分化过程的能力仍有待发现。 使用设计用于检测迄今为止鉴定的大多数哺乳动物miRNA的寡核苷酸阵列，我们测量了胶质母细胞瘤中miRNA的表达水平。 这项初步研究确定了一组在胶质母细胞瘤中上调的miRNA。 在这一簇中，一种miRNA显著升高。 序列特异性抑制这种miRNA与修饰的反义寡核苷酸诱导培养的胶质母细胞瘤细胞的凋亡，这表明了这种miRNA在胶质瘤发生中的作用。 肿瘤细胞特有的类似调节性miRNA分子可能存在，并可作为预后标志物，并可能成为治疗高级别脑肿瘤的良好治疗靶点。 该提案的长期目标是通过靶向miRNA治疗胶质母细胞瘤。 未来两年的直接目标是开发识别和验证miRNA靶点所需的技术。 我们将创建一个寡核苷酸阵列，用于完整分析胶质母细胞瘤中的miRNA表达，并表征仅在这些肿瘤中表达的分子。 然后，我们将开发在胶质母细胞瘤细胞培养中抑制这些miRNA的方法，并评估对肿瘤细胞迁移、凋亡和增殖能力的影响。 此外，我们将在体内动物模型中测试miRNA抑制剂的潜力。 虽然超出了这个提议的范围，但在接下来的几年里，我们将研究介导miRNA功能的下游mRNA和蛋白质靶点。 本文提出的实验结果将提高我们对脑肿瘤生物学的理解。 此外，这项研究中开发的miRNA靶向技术可以为胶质母细胞瘤的新治疗方法打开大门。

DESCRIPTION (provided by applicant): MicroRNAs (miRNAs) are a recently discovered class of small 20-22 nucleotide non-coding RNA molecules that have been shown to regulate target gene expression in various organisms. By targeting the mRNA of protein-coding genes for either cleavage or repression of translation, miRNAs are thought to play critical roles in development, control of growth, proliferation, and cell lineage determination. However, the ability of this new class of regulatory RNAs to influence the processes of proliferation and differentiation in malignancy remains to be uncovered. Using an oligonucleotide array designed to detect the majority of mammalian miRNAs identifies thus far, we measured the expression levels of miRNAs in glioblastomas. This preliminary study identified a cluster of miRNAs that is up-regulated in glioblastomas. Among this cluster one miRNA is markedly elevated. Sequence-specific inhibition of this miRNA with modified antisense oligonucleotides induces apoptosis of glioblastoma cells in culture, suggesting a role for this miRNA in gliomagenesis. Similar regulatory miRNA molecules unique to tumor cells may exist and can serve as prognostic markers and, probably, excellent therapeutic targets for the treatment of high-grade brain tumors. The long-term goal of this proposal is to treat glioblastomas by targeting miRNAs. The immediate goal over the next two years is the development of technologies required for identification and validation of miRNA targets. We will create an oligonucleotide array for the complete profiling of miRNA expression in glioblastomas and characterize molecules expressed exclusively in these tumors. We will then develop ways to suppress these miRNAs in glioblastoma cell cultures and assess the effects on the migratory, apoptotic, and proliferative capacity of the tumor cells. Furthermore, we will test the potential of the miRNA inhibitors in animal models in vivo. Although beyond the scope of this proposal, in the ensuing years we will study downstream mRNA and protein targets that mediate miRNA functions. The results of the experiments proposed here will improve our understanding of biology of brain rumors. Moreover, miRNA targeting technology developed in this research could open the door to novel treatments of glioblastoma.