Mechanisms of aberrant ribosomal RNA (rRNA) methylation and altered mRNA translation in cancers

项目摘要 mRNA翻译的保真度对于维持细胞内稳态和防止细胞内毒素的产生是至关重要的。 可能导致疾病发展的异常蛋白质。核糖体是核心的关键组成部分 翻译机器，其活性可以通过不同类型的核苷酸甲基化来调节。 核糖体RNA（rRNA）。越来越多的证据表明，rRNA甲基化的模式改变， 癌症，导致合成专门的核糖体，具有独特的翻译mRNA编码的能力， 致癌蛋白质。rRNA甲基化已显示动态调节核糖体功能， 影响其效率、准确性和对某些类型mRNA亲和力。因此，调控rRNA的途径 甲基化可以选择性地驱动支持细胞转化和肿瘤的蛋白质组的翻译， 发展我们的首要目标是确定参与调节异常的细胞的途径和关键参与者。 癌症中rRNA的甲基化，因为它们代表未开发的治疗靶标。我们最近发现 癌基因Pelp 1是癌细胞中rRNA甲基化的重要调节因子。我们的实验方法， 初步数据支持，是阐明Pelp 1调节rRNA甲基化的机制， 证明了这一过程对癌症进展的重要性。我们假设Pelp 1支持 通过其调节rRNA甲基化的能力来调节核糖体翻译活性，从而抑制肿瘤发生。在 我们将确定Pelp 1是否通过募集RNA甲基转移酶到rRNA基因来调节rRNA甲基化。 新生rRNA转录物。由于rRNA甲基化在调节转录水平中起着重要作用， 核糖体的能力，我们将评估Pelp 1的过表达是否改变核糖体的效率，保真度， 和亲和力的某些类型的mRNA使用翻译报告分析和多核糖体分析测序 方法（目标2）。Pelp 1在60-80%的乳腺癌中过表达，其表达水平直接影响乳腺癌的预后。 与肿瘤分级、转移和内分泌治疗抗性相关。在目标3中，我们将使用正交 小鼠乳腺癌模型，以评估是否需要Pelp 1调节rRNA甲基化的能力 来支持肿瘤发生。我们的研究结果表明，通过调节rRNA甲基化，Pelp 1参与了细胞的增殖。 癌细胞的翻译重编程，从而促进致癌基因的选择性翻译。的 成功完成我们提出的研究将产生重要的见解异常mRNA的机制 翻译及其在肿瘤发生中的作用。

Project Summary The fidelity of mRNA translation is essential to maintain cellular homeostasis and prevent the production of aberrant proteins that could lead to disease development. Ribosomes are key components of the core translational machinery whose activity can be modulated by diverse types of nucleotide methylation on the ribosomal RNA (rRNA). A growing body of evidence indicates that the pattern of rRNA methylation is altered in cancers, leading to the synthesis of specialized ribosomes with the unique ability to translate mRNAs coding for oncogenic proteins. rRNA methylation has been shown to dynamically regulate ribosome function and influence their efficiency, accuracy and affinity for certain type of mRNAs. Hence, pathways regulating rRNA methylation can selectively drive the translation of a proteome that supports cellular transformation and tumor development. Our overarching goal is to identify pathways and key players involved in regulating the aberrant methylation of rRNA in cancers as they represent unexploited therapeutics targets. We recently uncovered that the oncogene Pelp1 is an important regulator of rRNA methylation in cancer cells. Our experimental approach, supported by preliminary data, is to elucidate the mechanisms by which Pelp1 regulates rRNA methylation and demonstrate the importance of this process for cancer progression. We hypothesize that Pelp1 supports tumorigenesis by modulating ribosomes translational activity through its ability to regulate rRNA methylation. In Aim1 we will determine whether Pelp1 regulates rRNA methylation by recruiting RNA methyltransferases to the nascent rRNA transcript. Because rRNA methylation plays an important role in regulating the translational capacity of ribosomes, we will assess whether overexpression of Pelp1 changes ribosome efficiency, fidelity, and affinity for certain types of mRNAs using translation reporter assays and a polysome profiling-sequencing approach (Aim 2). Pelp1 is overexpressed in 60-80% of breast cancers, where its level of expression directly correlates with tumor grade, metastasis, and endocrine therapy resistance. In Aim 3, we will use orthotopic mouse model of breast cancer to assess whether the ability of Pelp1 to regulate rRNA methylation is required to support tumorigenesis. Our findings suggest that by regulating rRNA methylation, Pelp1 participates in the translational reprograming of cancer cells, thereby promoting the selective translation of oncogenic genes. The successful completion of our proposed study will yield important insight into mechanisms of aberrant mRNA translation and it roles in oncogenesis.