Clinical and Translational Research
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Apr 16, 2022; 10(11): 3352-3368
Published online Apr 16, 2022. doi: 10.12998/wjcc.v10.i11.3352
Identification of circ_0000375 and circ_0011536 as novel diagnostic biomarkers of colorectal cancer
Teng-Fei Yin, Shi-Yu Du, Dong-Yan Zhao, Xi-Zhen Sun, Yuan-Chen Zhou, Qian-Qian Wang, Ge-Yu-Jia Zhou, Shu-Kun Yao
Teng-Fei Yin, Shi-Yu Du, Yuan-Chen Zhou, Qian-Qian Wang, Shu-Kun Yao, Graduate School, Peking University China-Japan Friendship School of Clinical Medicine, Beijing 100029, China
Shi-Yu Du, Dong-Yan Zhao, Ge-Yu-Jia Zhou, Shu-Kun Yao, Department of Gastroenterology, China-Japan Friendship Hospital, Beijing 100029, China
Dong-Yan Zhao, Xi-Zhen Sun, Ge-Yu-Jia Zhou, Graduate School, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100730, China
Xi-Zhen Sun, Department of Gastroenterology, Beijing Jishuitan Hospital, Beijing 100035, China
Author contributions: Yin TF conceived and designed the study, performed sample collection and formal analysis, and prepared the original draft; Du SY, Zhao DY and Sun XZ participated in sample acquisition, data analysis and manuscript revision; Zhou YC, Wang QQ and Zhou GYJ reviewed and edited the manuscript critically; Yao SK designed and supervised the study, revised the manuscript, and obtained the funding; all authors read and approved the final manuscript.
Supported by the National Key Development Plan for Precision Medicine Research, No. 2017YFC0910002.
Institutional review board statement: This study was approved by the Ethics Committee of China-Japan Friendship Hospital, No. 2018-116-K85-1.
Informed consent statement: All participants signed written informed consent.
Conflict-of-interest statement: There are no conflicts of interest to report.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Shu-Kun Yao, MD, PhD, Doctor, Professor, Graduate School, Peking University China-Japan Friendship School of Clinical Medicine, No. 2 Yinghua East Road, Chaoyang District, Beijing 100029, China. shukunyao@126.com
Received: October 29, 2021
Peer-review started: October 29, 2021
First decision: December 27, 2021
Revised: December 30, 2021
Accepted: February 12, 2022
Article in press: February 12, 2022
Published online: April 16, 2022
Processing time: 161 Days and 5.7 Hours
Abstract
BACKGROUND

Colorectal cancer (CRC) imposes a tremendous burden on human health, with high morbidity and mortality. Circular ribonucleic acids (circRNAs), a new type of noncoding RNA, are considered to participate in cancer pathogenesis as microRNA (miRNA) sponges. However, the dysregulation and biological functions of circRNAs in CRC remain to be explored.

AIM

To identify potential circRNA biomarkers of CRC and explore their functions in CRC carcinogenesis.

METHODS

CircRNAs and miRNAs differentially expressed in CRC tissues were identified by analyzing expression profiles from the Gene Expression Omnibus (GEO) database. Circ_0000375 and circ_0011536 were selected as CRC biomarker candidates. Quantitative real-time polymerase chain reaction was utilized to evaluate the expression of these 2 circRNAs in CRC tissues, serums and cell lines. Receiver operating characteristic curves were generated to assess the diagnostic performances of these 2 circRNAs. Then, functional experiments, including cell counting kit-8, wound healing and Transwell invasion assays, were performed after the overexpression of circ_0000375 and circ_0011536 in CRC cell lines. Furthermore, candidate target miRNAs of circ_0000375 and circ_0011536 were predicted via bioinformatics analysis. The expression levels of these miRNAs were explored in CRC cell lines and tissues from GEO datasets. A luciferase reporter assay was developed to examine the interactions between circRNAs and miRNAs. Based on the target miRNAs and downstream genes, functional enrichment analyses were applied to reveal the critical signaling pathways involved in CRC carcinogenesis.

RESULTS

Downregulated circ_0000375 and circ_0011536 expression was observed in CRC tissues in GSE126095, clinical CRC tissue and serum samples and CRC cell lines. The areas under the curve for circ_0000375 and circ_0011536 were 0.911 and 0.885 in CRC tissue and 0.976 and 0.982 in CRC serum, respectively. Moreover, the serum levels of these 2 circRNAs were higher in patients at 30 d postsurgery than in patients before surgery, suggesting that the serum expression of circ_0000375 and circ_0011536 is related to CRC tumorigenesis. Circ_0000375 and circ_0011536 overexpression inhibited the proliferation, migration and invasion of CRC cells. Furthermore, miR-1182 and miR-1246, which were overexpressed in CRC tissues in GSE41655, GSE49246 and GSE115513, were verified as target miRNAs of circ_0000375 and circ_0011536, respectively, by luciferase reporter assays. The downstream genes of miR-1182 and miR-1246 were enriched in some CRC-associated pathways, such as the Wnt signaling pathway.

CONCLUSION

Circ_0000375 and circ_0011536 may function as tumor suppressors in CRC progression, serving as novel biomarkers for CRC diagnosis and as promising candidates for therapeutic exploration.

Keywords: Cir_0000375; Circ_0011536; MicroRNA; Biomarker; Colorectal cancer; Tumor suppressor

Core Tip: The dysregulation and biological functions of circular ribonucleic acids (circRNAs) in colorectal cancer (CRC) have not been well elucidated. In this study, circ_0000375 and circ_0011536 were observed to be downregulated in CRC tissues, serum samples and cell lines. These 2 circRNAs were validated as biomarker candidates in tissues and serum samples with high diagnostic performance. Overexpression of circ_0000375 and circ_0011536 inhibited the growth, migration and invasion of CRC cells. Furthermore, miR-1182 and miR-1246 were upregulated in CRC tissues as target microRNA of circ_0000375 and circ_0011536, respectively. Overall, circ_0000375 and circ_0011536 may serve as diagnostic biomarkers and function as tumor suppressors in CRC.