Wu Jiangxue, Tan Xin, Lin Jiaxin, Yuan Luping, Chen Jiemin, Qiu Lin, Huang Wenlin
1 State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center , Guangzhou, China .
2 Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center , Guangzhou, China .
Hum Gene Ther. 2017 May;28(5):415-427. doi: 10.1089/hum.2016.136. Epub 2016 Dec 29.
MicroRNAs (miRNAs) are important post-transcriptional regulators that control cancer development and progression. However, the application of miRNA therapy in cancer has been hampered by a lack of an efficient and targeted delivery system. In our previous studies, an oriP promoter-based minicircle system successfully mediated targeted foreign gene expression in EBNA1-positive nasopharyngeal carcinoma (NPC). However, it remains to be evaluated whether this system can be applied for tumor miRNA therapy. miR-31-5p, a tumor suppressive miRNA involved in the tumorigenesis of EBV-positive NPC, was selected as the therapeutic miRNA to be transferred. In this work, we constructed a novel EBNA1-specific miRNA expression system, minicircle-oriP-miR-31. The results indicated that mc-oriP-miR-31 mediated selective miR-31-5p expression in EBNA1-positive NPC cells. Both the proliferation and migration of EBNA1-positive NPC cell lines were inhibited by mc-oriP-miR-31 treatment in vitro. Furthermore, mc-oriP-miR-31 treatment inhibited xenograft growth and lung metastasis in vivo. We also identified WDR5 as a novel miR-31-5p target. Knockdown of WDR5 inhibited NPC cell proliferation and migration and was associated with downregulation of Notch1. Reintroduction of WDR5 partially abrogated the suppressive effects induced by miR-31-5p. In conclusion, we demonstrate for the first time that targeted expression of miR-31-5p using a nonviral minicircle vector can serve as a novel approach for tumor miRNA therapy. Moreover, WDR5 may be a promising therapeutic target for NPC treatment.
微小RNA（miRNA）是重要的转录后调节因子，可控制癌症的发生和发展。然而，由于缺乏高效的靶向递送系统，miRNA疗法在癌症治疗中的应用受到了阻碍。在我们之前的研究中，基于oriP启动子的微环系统成功介导了EBNA1阳性鼻咽癌（NPC）中外源基因的靶向表达。然而，该系统是否可应用于肿瘤miRNA治疗仍有待评估。miR-31-5p是一种参与EBV阳性NPC肿瘤发生的肿瘤抑制性miRNA，被选为要转移的治疗性miRNA。在这项工作中，我们构建了一种新型的EBNA1特异性miRNA表达系统，即微环-oriP-miR-31。结果表明，mc-oriP-miR-31介导了EBNA1阳性NPC细胞中miR-31-5p的选择性表达。体外实验中，mc-oriP-miR-31处理可抑制EBNA1阳性NPC细胞系的增殖和迁移。此外，mc-oriP-miR-31处理在体内可抑制异种移植瘤生长和肺转移。我们还确定WDR5是一种新的miR-31-5p靶点。敲低WDR5可抑制NPC细胞的增殖和迁移，并与Notch1的下调有关。重新引入WDR5可部分消除miR-31-5p诱导的抑制作用。总之，我们首次证明使用非病毒微环载体靶向表达miR-31-5p可作为肿瘤miRNA治疗的一种新方法。此外，WDR5可能是NPC治疗中一个有前景的治疗靶点。
