Basic Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 7, 2018; 24(5): 573-582
Published online Feb 7, 2018. doi: 10.3748/wjg.v24.i5.573
Hsa-miR-202-3p, up-regulated in type 1 gastric neuroendocrine neoplasms, may target DUSP1
Dou Dou, Yan-Fen Shi, Qing Liu, Jie Luo, Ji-Xi Liu, Meng Liu, Ying-Ying Liu, Yuan-Liang Li, Xu-Dong Qiu, Huang-Ying Tan
Dou Dou, Yuan-Liang Li, Xu-Dong Qiu, Department of Integrative Oncology, China-Japan Friendship Hospital; Beijing University of Chinese Medicine, Beijing 100029, China
Yan-Fen Shi, Jie Luo, Department of Pathology, China-Japan Friendship Hospital, Beijing 100029, China
Qing Liu, Meng Liu, Huang-Ying Tan, Department of Integrative Oncology, China-Japan Friendship Hospital, Beijing 100029, China
Ji-Xi Liu, Department of Gastroenterology, China-Japan Friendship Hospital, Beijing 100029, China
Ying-Ying Liu, Department of Integrative Oncology, Luoyang Central Hospital Affiliated to Zhengzhou University, Luoyang 471009, Henan Province, China
Author contributions: Dou D and Shi YF contributed equally to this work and should be considered co-first authors; Tan HY, Dou D and Shi YF designed the research; Dou D, Liu Q, Liu JX, and Li YL performed the research; Shi YF, Luo J and Qiu XD analyzed the data; Dou D, Liu M and Liu YY wrote the paper; Shi YF and Tan HY revised the paper.
Supported by the National Natural Science Foundation of China, No. 81673763.
Institutional review board statement: The study was reviewed and approved by the China-Japan Friendship Hospital Institutional Review Board.
Conflict-of-interest statement: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the reported research.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Huang-Ying Tan, MD, PhD, Professor, Department of Integrative Oncology, China-Japan Friendship Hospital, No. 2, Yinghuadong Street, Beijing 100029, China. tanhuangying@263.net
Telephone: +86-10-53236555 Fax: +86-10-53236555
Received: November 5, 2017
Peer-review started: November 6, 2017
First decision: November 22, 2017
Revised: December 3, 2017
Accepted: December 12, 2017
Article in press: December 12, 2017
Published online: February 7, 2018
Processing time: 86 Days and 10.4 Hours
ARTICLE HIGHLIGHTS
Research background

Type 1g-NEN is a kind of rare malignant tumor. Because its recurrence rate is relatively high, the molecular mechanism of this disease urgently needs to be explored. MiRNAs play important roles in the occurrence and development of tumors. At present, studies on the role of miRNAs in type 1 g-NEN are quite few. This study may provide some potential therapeutic targets for the prevention of type 1 g-NEN recurrence.

Research motivation

The main topic of this study is the molecular mechanism of type 1 g-NENs. The key issue to be solved is which miRNAs and their target genes could affect the process of tumor recurrence. In future research, our study may help to explain the mechanism of some existing treatment and provide new therapeutic targets for type 1 g-NEN therapy.

Research objectives

The main objective of this study was to discover some type 1 g-NEN associated miRNAs and find their target genes. In this study, the differential miRNA expression between tumor lesions and tumor-free gastric mucosa was described, and the target gene of miRNA-202-3p was found. These may provide a basis for further revealing the molecular mechanism of type 1 g-NEN recurrence in the future.

Research methods

Four main technologies were used in this study. First, we used Agilent human miRNA chips to find the differential miRNA expression between tumor lesions and tumor-free gastric mucosa. This kind of chip is expensive, but covers all known human miRNAs. Second, the results of chips were validated via RT-PCR, which is a proven and reliable experimental method to obtain a more accurate conclusion. Third, we used bioinformatics to look for target genes on web (TargetScan, PITA, and microRNAorg). This technique can quickly help us narrow down the scope of target genes. Last, a dual-luciferase reporter assay system was used for verification of the target gene. This system can show clearly the influence of miRNAs on its target gene. All the above research methods have been rarely applied to g-NENs before.

Research results

The high expression of miR-202-3p in type 1 g-NENs was found, which indicates that miR-202-3p acts as a tumor-promoting miRNA. The dual-luciferase reporter assay system showed the relationship between miR-202-3p and DUSP1, confirming that the high expression of miR-202-3p leads to the downregulation of DUSP1. Therefore, we speculate that DUSP1 is a tumor suppressor gene in type 1 g-NENs. Since g-NEN is a rare disease, there are no ready-made cell lines and we had to conduct the dual-luciferase experiment in 293T cells (a well-established tool cell for dual-luciferase experiment). Our next step is to carry out the primary culture of ECL cells to further validate our findings.

Research conclusions

In this study, we summarized the existing mechanisms of type 1 g-NENs and confirmed the difference of miRNA expression between tumor and non-tumor gastric mucosa. Our study found that miRNA-202-3p was overexpressed in type 1 g-NENs and DUSP1 was its target gene and put forward an assumption: In normal situation, although hypergastrinaemia leads to ECL cell proliferation, the cells could be prevented from dysplasia if DUSP1 is expressed normally. However, when the DUSP1 is down-regulated by the highly expressed miR-202, ECL cells will have more opportunities to develop to type 1 g-NENs. This will help clinicians to further understand the molecular mechanism of the disease.

Research perspectives

Our next step is to carry out the primary culture of ECL cells to further validate our findings. Our previous clinical study has found that Chinese herbal medicine can extend the median disease-free survival (DFS). So, using cell models to explore whether Chinese herbal medicine can regulate the expression of miRNA-202-3p/DUSP1 is the best method for the future research.