microRNA-506在卵巢癌上皮-间质转化中的作用及机制研究

Ovarian cancer (OvCa) is the most lethal gynaecological malignancy and the majority of patients with OvCa die from tumor recurrence and metastasis. In our preliminary study, we analyzed the genomic and epigenetic data of 459 cases of OvCa in TCGA (The Cancer Genome Atlas) using integrated bioinformatics analysis and discovered a microRNA network that is related to a mesenchymal subtype with poor survival. In this network, 6 key microRNAs and many of their target genes have been shown in literature to be associated with epithelial-mesenchymal transition (EMT). MiR-506 is a novel microRNA in this network and its expression is negatively correlated with the expression of some EMT-related genes, suggesting that miR-506 probably plays a role in controlling EMT. In this project, we seek to characterize the role and mechanism of miR-506 in EMT of OvCa through a series of in vitro and in vivo experiments as well as retrospective clinical correlation analysis. We will also evaluate the effect of miR-506/ nanoliposomes for suppression of OvCa xenografts in mice as a preclinical study. The results of this project will contribute to our understanding of the mechanism of OvCa spread, metastasis, and the role of EMT in these processes. This project may also test a potentially new strategy for OvCa therapy.

卵巢癌是致死率最高的一类妇科恶性肿瘤，大多数患者死于肿瘤复发或转移。在前期研究中，通过对肿瘤基因组计划（The Cancer Genome Atlas, TCGA）459例卵巢癌的系统分析，发现一个与预后不良间质亚型有关的microRNA调节网络。在此网络中，6个microRNA及其下游多个靶基因均已被证实与肿瘤上皮-间质转化（epithelial-mesenchymal transition, EMT）有关。鲜见报道的miR-506是这个网络中的关键microRNA，与多个EMT相关靶基因的表达呈负相关，提示它可能参与卵巢癌EMT调控。本项目拟通过体外、体内实验与临床病例分析，验证miR-506在卵巢癌EMT中的作用及机制；并评估miR-506/纳米脂质体对裸鼠移植瘤的抑制作用，为阐述卵巢癌的侵袭转移机制与肿瘤EMT的调控机制提供新思路和理论依据，并为卵巢癌的治疗提供新方向和实验基础。

卵巢癌是致死率最高的一类妇科恶性肿瘤，大多数患者死于肿瘤的复发和转移。上皮-间质转化（epithelial-mesenchymal transition, EMT）与肿瘤的侵袭转移密切相关。本课题组通过对肿瘤基因组计划（The Cancer Genome Atlas, TCGA）数据库中459 例卵巢癌的系统分析，发现了一个与卵巢癌EMT有关的microRNA-mRNA调节网络，而miR-506 是这个网络中的一个关键microRNA。本项目通过体外诱导和抑制实验证实了miR-506 对卵巢癌细胞生物学行为及EMT 标志物表达的影响，并通过miR-506逆转TGF-β诱导的EMT，验证了miR-506对EMT及细胞侵袭能力的抑制作用；通过荧光素酶报告基因技术验证了miR-506 对SNAI2、VIM、CDH2的调控作用，证实miR-506通过多条通路调控卵巢癌的EMT：1. miR-506直接与SNAI2的3’-UTR结合，抑制SNAI2的表达，进而上调E-cadherin的表达，从而抑制EMT；2. miR-506与VIM的3’-UTR结合，直接抑制间叶标记物vimentin的表达，抑制EMT；3. miR-506与CDH2的3’-UTR结合，抑制N-cadherin的表达，抑制EMT。对卵巢癌裸鼠移植瘤模型给予纳米包被的miR-506或阴性对照miR-Ctrl，不仅证实了miR-506 对卵巢癌生长、侵袭、转移的抑制作用，而且验证了miR-506对上述靶基因的负向调控作用。最后，在中国200余例卵巢癌组织中证实了miR-506与较早的分期、较好的生存的有关，并验证了其与上述靶基因表达的负相关关系。本项目的研究成果在Cancer Cell、JNCI、Journal of Pathology等高水平杂志发表，不仅被Cancer Cell、Journal of Pathology与Chinese Journal of Cancer作为封面文章重点报道，而且被Cancer Cell评为2013年最佳文章。本项目不仅证实了miR-506对卵巢癌EMT 的抑制作用及其分子机制，提示miR-506 用于卵巢癌治疗的可能性，并带动了miR-506在各种肿瘤中的研究，大数据分析、体内外实验及临床病例层层验证的研究模式也为科研工作者成功地进行原创性研究积累了经验。