长链非编码RNA TP73-AS1通过招募eIF4A3/吸附miR-27a 促进胆管癌发生发展的机制研究

Emerging evidence documented that the dysregulation of long non-coding RNAs (lncRNAs) is critically involved in tumorigenesis and progression of malignancies. Our previous study demonstrated that up-regulated TP73-AS1 facilitates malignant biological behaviors of cholangiocarcinoma (CCA) by recruiting eIF4A3, thereby suppressing the translation of underlying targets. Additionally, TP73-AS1 acts as a competing endogenous RNA to absorb miR-27a and elevate the expression of SP1. SP1 could then enter into the nucleus and bind to the promoter region of TP73-AS1 to activate its transcription. Therefore, we hypothesize the underlying mechanisms of TP73-AS1 depends on regulating its downstream targets expression at translational level. Moreover, TP73-AS1 sponges miR-27a to release its suppression on SP1. SP1 could bind to the promoter region of TP73-AS1 and activate its transcription. Different cell lines, nude mice models as well as clinical serum and tissue samples are subjected to the techniques including molecular biology, cytobiology and experimental zoology to establish the molecular regulatory network of TP73-AS1 and illuminate its underlying mechanisms. The present study will provide a potential target and new perspective for the prevention and treatment of CCA.

研究显示，长链非编码RNA的异常表达与恶性肿瘤的发生发展密切相关。项目组基于前期研究发现：胆管癌中高表达的lncRNA TP73-AS1一方面通过招募eIF4A3抑制靶基因的翻译从而促进肿瘤恶性生物学行为；另一方面，TP73-AS1作为竞争性内源RNA靶向吸附miR-27a，在转录后水平促进SP1表达；同时，上调的SP1能够结合TP73-AS1的转录子区域并促进其转录。因此，我们提出科学假设：胆管癌中失调控的TP73-AS1通过招募eIF4A3于翻译水平通过对下游靶基因表达的调控来实现其对胆管癌发生发展的促癌作用并通过吸附miR-27a上调SP1维持其自身的持续性高表达状态。本项目将利用多种细胞系、不同的动物模型并结合大量临床组织样本通过分子生物学、细胞生物学、实验动物学等多种实验手段建立TP73-AS1在胆管癌细胞内的分子调控网络并揭示其作用机制，为胆管癌的预防和治疗提供新的靶点和思路。

长链非编码RNA的异常表达与恶性肿瘤的发生发展密切相关。本研究中证实TP73-AS1在胆管癌中高表达且与更大的肿瘤直径和更高的TNM分期密切相关。TP73-AS1对在体内外水平促进胆管癌细胞增殖和转移，且不影响正常胆道上皮细胞的增殖和凋亡。此外，转录因子SP1通过与TP73-AS1启动子结合并促进TP73-AS1转录。在体外水平，Huaier通过下调TP73-AS1的表达抑制胆管癌细胞的增殖、侵袭和转移，同时通过干扰线粒体功能、诱导氧化应激和激活caspase促进胆管癌细胞的凋亡。Huaier还可以通过调节增殖和EMT相关蛋白的表达来抑制肿瘤的生长和转移。在体内水平，Huaier显著抑制胆管癌肿瘤的生长和肺转移。最后，Huaier可延长肺转移瘤模型裸鼠的生存期。本研究可能对胆管癌的个体化靶向治疗提供新的思路和靶点。