新候选癌基因microRNA-4707-5p促进食管鳞状细胞癌转移的作用及机制研究

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumor in China, which is prone to invasion, metastasis and poor prognosis. Our previous result of the whole genome sequencing and gene expression detection showed abnormal amplification and high expression of miR-4707-5p in ESCC tissues. More importantly, its high expression is positively related with patients’ poor prognosis and regional lymph node metastasis. In vitro experiments showed that over expression of miR-4707-5p could promote the migration and invasion abilities of ESCC cells. Our results also showed that miR-4707-5p could suppress the expression of E-cadherin, a key molecular of Epithelial-mesenchymal transition (EMT), and up-regulate the expression of total β-catenin. However, the molecular mechanism of miR-4707-5p’s metastasis-promoting function in ESCC remains unclear. In this study, bioinformatic prediction combined with mRNA expression profile detection strategy will be used to comprehensively screen metastasis related target genes of miR-4707-5p; Candidate target genes related to EMT process and/or Wnt/β-catenin pathway will get extra attention. The gene regulation network of miR-4707-5p in ESCC will be intensively investigated. Then we will test and verify the candidate target genes and the corresponding regulation network in ESCC cohort established by our research group. The objective of this study is to elucidate the molecular mechanism of miR-4707-5p’s metastasis promoting role, and to provide novel biomarker as well as potential therapeutic target for ESCC.

食管鳞状细胞癌易于发生转移，预后差。我们前期对食管鳞癌组织的全基因组测序和基因表达检测发现了miR-4707-5p的异常扩增和高表达，且其高表达与患者的不良预后及区域淋巴结转移相关。体外实验表明miR-4707-5p可显著促进食管鳞癌细胞的迁移和侵袭。尽管我们已确定miR-4707-5p可在细胞水平抑制上皮-间质转化（EMT）关键分子E-钙粘素的表达，并可上调β-catenin的水平，但其促进食管鳞癌转移的具体分子机制仍有待深入研究。本研究将采用生物信息学预测联合表达谱芯片分析的策略全面筛选miR-4707-5p与肿瘤转移、浸润相关的靶基因，特别是对肿瘤转移密切相关的EMT及Wnt/β-catenin通路有调控作用的靶基因组合，构建miR-4707-5p在食管鳞癌中的基因调控网络；并在食管鳞癌研究队列中验证靶基因及相应调控网络。以期阐明miR-4707-5p促进食管鳞癌转移的分子机制。

食管鳞状细胞癌（ESCC）为我国常见的恶性肿瘤，易于发生浸润和转移，预后差。我们通过对10对食管鳞癌组织进行的全基因组深度测序和基因表达检测发现了miR-4707-5p的异常扩增和高表达，且其高表达与患者的不良预后及区域淋巴结转移相关。体外细胞实验表明miR-4707-5p可显著促进食管鳞癌细胞的迁移和侵袭；在裸鼠肿瘤转移模型中，我们发现过表达miR-4707-5p显著促进了食管癌细胞从足底到腘窝淋巴结的转移以及尾静脉注射的食管癌细胞向肺部的转移。我们通过对稳定过表达miR-4707-5p的食管鳞癌细胞株的RNA-seq分析构建了miR-4707-5p在食管鳞癌中的调控网络，发现其主要通过调控Fanconi anemia pathway, NF-kappa B signaling pathway和Adherens junction等信号通路从而发挥癌基因的作用。我们进一步证实了ADARB1是miR-4707-5p在食管鳞癌中的直接作用靶基因，且二者在食管癌组织中的表达水平呈显著负相关；过表达miR-4707-5p可以显著抑制ADARB1的表达、下调E-cadherin从而激活Wnt/β-catenin信号通路，促进肿瘤的转移。我们的进一步分析显示，miR-4707-5p在其他多种肿瘤中的表达及功能与食管鳞癌截然不同。miR-4707-5p在肺鳞癌、结直肠癌和头颈鳞癌中呈显著低表达，过表达miR-4707-5p可以显著抑制肺鳞癌细胞株的增殖。我们的研究结果提示miR-4707-5p在不同肿瘤中的作用存在多样性和复杂性，阐明了其促进食管鳞癌转移的分子机制，为食管鳞癌的预测、预后及治疗提供新的潜在靶标。此外，我们所进行的其他研究还发现ARAD2基因可以通过编辑IGFBP7在食管鳞癌中发挥抑癌基因的作用；WWC2基因可通过Hippo信号通路抑制肝细胞癌的侵袭和转移；鉴定了高激活水平的EB病毒亚型，为更深入的理解鼻咽癌发病的地区差异提供了重要切入点。项目执行期间发表标注SCI论文4篇，其中影响因子>5.0的一篇，培养研究生2名。