Control of Breast Cancer Metastasis by Epstein-Barr Virus microRNA

项目总结 作用于RNA的腺苷脱氨酶(ADAR)将dsRNA(A-DNA)中的腺苷特异性地转化为肌苷。 TO-I RNA编辑)。我们的开创性研究表明，A-to-I RNA编辑参与了对 MiRNA的生物发生和功能。我们最近发现EBV(Epstein-Barr-Virus)miRNA miR- BART6结合到功能性RISC复合体上被其初级转录本(pri-miR-BART6)的A-to-I编辑所抑制 由ADAR1。此外，在人Disher mRNA中还发现了miR-BART6-5p的四个结合位点 3‘非编码区，揭示了EBV操纵宿主RNAi机制的独特策略。 肿瘤转移是包括乳腺癌在内的癌症患者最常见的死亡原因。 上皮向间充质转化(EMT)在肿瘤转移中起重要作用。蜗牛、鼻涕虫和螺旋 已被确定为EMT的主要监管机构。除了这些常规的转录因子蛋白外， MiRNAs已经成为控制EMT的新的关键因素。最近的研究表明，有两个miRNAs，miR- 103和miR-107，通过沉默Dester从而抑制miRNAs的全球合成来促进EMT， 包括一种主要的EMT抑制因子miR-200。 EBV是最常见的人类病毒之一，感染了世界90%以上的人口， EB病毒潜伏感染与多种人类癌症的关系 疾病，鼻咽癌是公认的疾病。在人类乳房中经常检测到EB病毒。 癌症标本。此外，在高级别(转移性)乳腺癌中更频繁地检测到EBV 已有报道称。然而，人们对EBV与乳腺癌病因和疾病的相关性知之甚少。 特殊的转移。我们最近的研究表明一种以前未曾探索过的可能性EBV感染可能 在乳腺肿瘤向转移的过程中起着重要作用。我们假设miR-BART6-5p和 经ADAR1编辑后，通过靶向转移器调控EMT，促进EBV阳性乳腺的转移 癌症。通过这项研究建议获得的信息可能会导致新的预防措施 或转移性乳腺癌的治疗。 这个项目的长期目标是更好地了解EBV miR-BART6在转移中的功能 通过A-to-I RNA编辑介导的调控机制。具体地说，我们将确定：1) MIR-BART6 RNA在促进人乳腺癌细胞株EMT中的作用；2)RNA编辑在人乳腺癌细胞中的意义 MiR-BART6的EMT促进作用；3)miR-BART6在乳腺癌转移中的体内作用 小鼠原位移植瘤模型；4)miR-BART6和ADAR1在小鼠体内的表达水平 人乳腺肿瘤标本及其与转移进展的相关性。

PROJECT SUMMARY Adenosine deaminase acting on RNA (ADAR) converts adenosine to inosine specifically in dsRNA (A- to-I RNA editing). Our pioneering studies demonstrated the involvement of A-to-I RNA editing in the control of miRNA biogenesis and function. We recently found that loading of the EBV (Epstein-Barr-virus) miRNA miR- BART6 onto a functional RISC complex is inhibited by A-to-I editing of its primary transcript (pri-miR-BART6) by ADAR1. Moreover, four binding sites of miR-BART6-5p were identified within the human Dicer mRNA 3'UTR, revealing a unique strategy of EBV to manipulate the host RNAi mechanism. Tumor metastasis is the most common cause of death in patients with cancer, including breast cancer. The Epithelial-to-Mesenchymal Transition (EMT) plays an important role in metastasis. Snail, Slug, and Twist have been identified as major regulators of EMT. In addition to these conventional transcription factor proteins, miRNAs have emerged as new key factors that control EMT. Recent studies suggest that two miRNAs, miR- 103 and miR-107, promote the EMT by silencing Dicer and thereby repressing global synthesis of miRNAs, including a major EMT-inhibitory miRNA, miR-200. EBV is one of the most common human viruses, infecting more than 90% of the world's population, and association of latent EBV infection with a variety of human cancers such as Burkitt's lymphoma, Hodgkin's disease, and nasopharyngeal carcinoma is well established. EBV is frequently detected in human breast cancer specimens. Furthermore, more frequent detection of EBV in higher grade (metastatic) breast cancers has been reported. However, very little is known about the relevance of EBV to breast cancer causation and in particular metastasis. Recent studies by us indicate a previously unexplored possibility that EBV infection may play an important role in progression of breast tumors to metastasis. We hypothesize that miR-BART6-5p and its editing by ADAR1 control EMT through targeting Dicer, and contribute to metastasis of EBV positive breast cancer. Information obtained through this research proposal may lead to a new intervention for the prevention or therapeutic treatment of metastatic breast cancer. The long-term goal of this project is to better understand functions of EBV miR-BART6 in metastasis and the control mechanism mediated via A-to-I RNA editing. Specifically, we will determine: 1) the function of miR-BART6 RNAs in promotion of EMT in human breast cancer cell lines; 2) the significance of RNA editing in the EMT promoting function of miR-BART6; 3) the role of miR-BART6 in vivo in breast cancer metastasis using an orthotopic tumor implantation mouse model; and 4) the miR-BART6 and ADAR1 expression levels in human breast tumor specimens and their relevance to metastatic progression.