Zhu Weihua, Wang Yazhou, Zhang Dafang, Yu Xin, Leng Xisheng
Department of Hepatobiliary Surgery, Peking University People's Hospital, Beijing 100044, China.
Beijing Key Surgical Basic Research Laboratory of Liver Cirrhosis and Liver Cancer, Peking University People's Hospital, Beijing 100044, China.
Biochem Biophys Res Commun. 2018 Mar 18;497(4):963-970. doi: 10.1016/j.bbrc.2018.02.005. Epub 2018 Mar 1.
Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies. Recently, many kinds of microRNAs (miRNAs) have been found to play a significant role in development of PDAC. However, there is no investigation about expression and function of miR-7-5p in PDAC. In this study, we found that miR-7-5p was down-regulated in PDAC tissues and its low expression level indicated a poor survival rate for PDAC patients. By bioinformatic analysis, we found that miR-7-5p targeted SOX18, and there was a negative correlation between them in PDAC tissues. Then luciferase reporter and western blot assays were used to verify the binding of miR-7-5p on SOX18 3'UTR. Cell function assays demonstrated that miR-7-5p inhibited proliferation, migration and invasion of PANC-1 cells by targeting SOX18. The nude mouse tumorigenicity assay further proved that miR-7-5p targeted SOX18 to inhibit pancreatic cancer growth in vivo. In order to further understand the mechanism, we applied a transcription factor prediction tool to explore the underlying targets that transcripted by SOX18, and the result indicated that SOX18 was a transcription factor for gp130 (a subunit of IL-6 receptor), and ChIP assays was performed to prove this prediction. Furthermore, we detected the suppression of gp130/JAK2/STAT3 signaling pathway after silencing SOX18 in PANC-1 cells, which demonstrated the transcriptional activation role of SOX18 on gp130. Thus, our present study revealed that miR-7-5p targeted SOX18 to inhibit gp130/JAK2/STAT3 signaling pathway to exert its suppressing role in PDAC.
胰腺导管腺癌（PDAC）是最致命的恶性肿瘤之一。最近，人们发现多种微小RNA（miRNA）在PDAC的发展中发挥着重要作用。然而，目前尚无关于miR-7-5p在PDAC中的表达及功能的研究。在本研究中，我们发现miR-7-5p在PDAC组织中表达下调，其低表达水平提示PDAC患者生存率较低。通过生物信息学分析，我们发现miR-7-5p靶向SOX18，且在PDAC组织中它们之间呈负相关。随后，采用荧光素酶报告基因检测和蛋白质印迹分析来验证miR-7-5p与SOX18 3'UTR的结合。细胞功能实验表明，miR-7-5p通过靶向SOX18抑制PANC-1细胞的增殖、迁移和侵袭。裸鼠成瘤实验进一步证明，miR-7-5p靶向SOX18在体内抑制胰腺癌生长。为了进一步了解其机制，我们应用转录因子预测工具探索由SOX18转录的潜在靶点，结果表明SOX18是gp130（IL-6受体的一个亚基）的转录因子，并进行染色质免疫沉淀实验来证实这一预测。此外，我们检测了在PANC-1细胞中沉默SOX18后gp130/JAK2/STAT3信号通路的抑制情况，这证明了SOX18对gp130的转录激活作用。因此，我们目前的研究表明，miR-7-5p靶向SOX18抑制gp130/JAK2/STAT3信号通路，从而在PDAC中发挥其抑制作用。
