TAZ激活长链非编码RNA Zeb2-AS1促进口腔鳞癌侵袭转移的分子机制研究

Invasion and metastasis cascade is a key biological event during oral squamous cell carcinoma progression, which significantly dictates patients’ prognosis. Our previous findings have revealed that TAZ is a novel and pivotal mediator governing oral cancer invasion and metastasis. Transcriptional profiling in TAZ overexpression or knockdown cells has revealed a TAZ-modulated antisense lncRNA Zeb2-AS1 with unexplored functions. Our preliminary experiments and bioinformatics analyses have indicated that Zeb2-AS1 knockdown significantly impaired migratory potential and invasiveness of oral cancer cells. Moreover, TAZ directly activated Zeb2-AS1 transcription, which in turn recruited MLL1 to epigenetically upregulated cancer-metastasis associated Zeb2. In the present study, we aim at the regulatory mechanisms underlying oral cancer invasion and metastasis and focus on TAZ-Zeb2-AS1-Zeb2 regulatory axis. A series of experimental studies including gene overexpression, knockdown, rescue experiment, animal models and clinical samples as well as ChIP, RIP, RNA pull-down and promoter reporter assays, are scheduled to unravel the biological functions and molecular mechanisms mediated by TAZ-Zeb2-AS1-Zeb2 regulatory axis in oral cancer invasion and metastasis. Taken together, these findings might provide novel molecular biomarkers and therapeutic target for clinical diagnosis and treatment against oral squamous cell carcinoma metastasis.

肿瘤侵袭转移是口腔鳞癌发展过程中的核心生物学事件，严重影响患者的预后。我们前期研究发现：TAZ是调控口腔癌侵袭转移新的关键分子；Zeb2-AS1（简称ZA）是通过芯片技术分别筛选TAZ过表达和沉默细胞中转录表达谱差异时获得的、一条受TAZ调控且功能未知的反义lncRNA。预实验和生物信息学研究提示：ZA沉默可明显抑制口腔癌细胞的侵袭迁移；TAZ可直接转录激活ZA，而ZA可能通过募集MLL1以表观遗传修饰方式上调肿瘤转移相关基因Zeb2的表达。因此，本课题拟以口腔鳞癌侵袭转移为切入点，以TAZ-ZA-Zeb2调控轴为研究对象，采取过表达、沉默、挽救实验、动物模型构建和临床标本检测等策略，应用ChIP、RIP、RNA pull-down和荧光素酶报告等技术进行实验研究，旨在阐明TAZ-ZA-Zeb2调控轴在口腔鳞癌侵袭转移过程中的生物学作用及分子机制，为口腔鳞癌转移的临床诊疗提供新的分子靶标。

肿瘤侵袭转移是口腔鳞癌发展过程中的核心生物学事件。我们前期研究发现：TAZ是调控口腔癌侵袭转移新的关键分子；Zeb2-AS1（简称ZA）是通过芯片技术分别筛选TAZ过表达和沉默细胞中转录表达谱差异时获得的、一条受TAZ调控且功能未知的反义lncRNA。我们聚焦于TAZ调控的ZEB2-AS1，通过系列体内外实验，揭示：1. ZEB2-AS1在口腔鳞癌标本和细胞系中呈异常高表达，其表达水平肿瘤大小、颈淋巴转移、总体生存率以及无病生存率相关，是判断患者预后的独立因素；2. ZEB2-AS1基因沉默后口腔鳞癌细胞侵袭迁移能力显著下降，细胞增殖显著减弱、凋亡水平上升；3. ZEB2-AS1定位于胞核，其可通过调节ZEB2 mRNA的稳定性从参与头领鳞癌EMT过程，介导头颈鳞癌恶性表型的转化的生物学效应；4. 通过siRNA介导TEAD4沉默及TGF-β诱导EMT等实验，揭示TEAD4通过参与EMT过程调控口腔鳞癌恶性表型的转化；5. 口腔鳞癌细胞中TAZ与TEAD4结合后形成转录复合体与ZEB2-AS1启动子区结合激活ZEB2-AS1转录。本研究成果阐明TAZ/TEAD4-ZEB2-AS1通过调节ZEB2 mRNA稳定性进而促进EMT过程促进口腔鳞癌的侵袭转移, 为研发抗口腔鳞癌转移新治疗策略提供前期理论基础。