Basic Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 28, 2018; 24(4): 475-483
Published online Jan 28, 2018. doi: 10.3748/wjg.v24.i4.475
Overexpression of CREPT confers colorectal cancer sensitivity to fluorouracil
Yan-Shen Kuang, Yi Wang, Li-Dan Ding, Liu Yang, Ying Wang, Si-Han Liu, Bing-Tao Zhu, Xu-Ning Wang, Hong-Yi Liu, Jun Li, Zhi-Jie Chang, Yin-Yin Wang, Bao-Qing Jia
Yan-Shen Kuang, Xu-Ning Wang, Hong-Yi Liu, Bao-Qing Jia, General Surgery II Department, Chinese PLA General Hospital, Beijing 100853, China
Yi Wang, Li-Dan Ding, Liu Yang, Si-Han Liu, Bing-Tao Zhu, Zhi-Jie Chang, Yin-Yin Wang, State Key Laboratory of Membrane Biology, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
Jun Li, Institute of Immunology, PLA, The Third Military Medical University, Chongqing 400038, China
Author contributions: Kuang YS and Wang Y contributed equally to this work; Kuang YS performed the majority of experiments and analyzed the data; Wang Y contributed significantly to staining and analyzing of the immunohistochemistry experiments; Ding LD and Yang L helped perform the analysis with constructive discussions; Wang Y, Zhu BT and Li J helped perform the cell apoptosis detection; Wang XN and Liu HY contributed to obtaining the patients’ data; Jia BQ, Chang ZJ and Wang YY contributed to the conception and coordination of the study.
Supported by The Key Project Grant from the National Natural Science Foundation of China, No. 81372167, No. 81572729, No. 81402293, No. 81372372 and No. 81230044; and The National Key Research and Development Program of China, No. 2016YFA0500301.
Institutional review board statement: This study was approved by the Ethics Committee of the PLA General Hospital, Beijing, China. All patients involved in this study gave their informed consent for participation in the study.
Conflict-of-interest statement: We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript titled “Overexpression of CREPT confers colorectal cancer sensitivity to fluorouracil”.
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: Bao-Qing Jia, MD, PhD, Chief Doctor, Professor, General Surgery II Department, Chinese PLA General Hospital, 28th, Haidian Dist., Beijing 100853, China. jiabaoqing@301hospital.com.cn
Telephone: +86-18910566719 Fax:+86-10-66937533
Received: October 22, 2017
Peer-review started: October 25, 2017
First decision: November 14, 2017
Revised: November 23, 2017
Accepted: November 28, 2017
Article in press: November 28, 2017
Published online: January 28, 2018
Processing time: 95 Days and 13.3 Hours
ARTICLE HIGHLIGHTS
Research background

Colorectal cancer (CRC) is the third leading cancer and the third most frequent cause of cancer-related death in the United States. Cell cycle-related and expression-elevated protein in tumor (CREPT) is preferentially expressed in many kinds of carcinomas. However, the correlation between CREPT and CRC clinicopathological patterns remains unclear. Study of the impact of CREPT expression on the anticancer drug 5-fluorouracil (5-FU) resistance in CRC has been limited.

Research motivation

We investigated the expression pattern of CREPT in CRC and explored if CREPT rendered CRC cells sensitive to 5-FU.

Research objectives

We investigated the expression pattern of CREPT in CRC. To the best of our knowledge, this is the first study to explore the correlation between CREPT and CRC cell sensitivity to 5-FU. Our results lead us to consider CREPT as a potential chemotherapy predictive biomarker. Moreover, further study on the impact of CREPT on chemotherapy outcome in other cancers and on other antitumor drugs is needed.

Research methods

We analyzed tissue sections from 203 primary CRC patients and 13 benign colorectal adenoma patients using immunohistochemistry with anti-CREPT antibody. CREPT overexpressing/knockdown cell lines were established by lentivirus infection. Expression of CREPT in these cell lines was analyzed by western blotting and the cell viability was measured by CCK-8 assay. The cell lines were subjected to 5-FU treatment. The cytotoxic effect of 5-FU was measured by CCK-8 assay and poly (ADP-ribose) polymerase/flow cytometry analysis.

Research results

CREPT expression correlates with clinicopathological features in CRC. CREPT was abundantly expressed in CRC tissues compared with benign tissues. A significant increase in CREPT was detected in more highly differentiated tumors. The intensive staining signal was enriched in the malignant region in contrast to the margin and normal counterparts in the same slide. CREPT stimulated cell proliferation and the cell cycle in CRC cells. Cell growth was significantly enhanced when CREPT was overexpressed via exogenous transfection, while CREPT depletion markedly suppressed cell viability. Overexpression of CREPT sensitized CRC cells to 5-FU-induced apoptosis. Knock down of CREPT markedly suppressed cell proliferation. However, viability of CREPT-silenced DLD1 cells was significantly increased in comparison with control cells in response to 5-FU treatment, indicating that drug resistance was induced by CREPT deficiency. 5-FU elicited dramatic apoptosis in DLD1 cells.

Research conclusions

The impact of CREPT on CRC cell response to 5-FU was identified for the first time. We hypothesize that this phenomenon is attributed to an accelerated cell cycle induced by high expression of CREPT. However, the mechanism of this finding requires further study. Clinically, biomarkers for chemotherapy efficacy prediction are urgently needed and this research provides a candidate.

Research perspectives

There were a few limitations to this study. For example, compared to a public database, first-hand follow-up data of patients are more convincing. For the future, we are working on animal experiments to verify our findings in vivo. Then, we will investigate the mechanisms of action of CREPT, and the possibility of clinical application of CREPT as a prognostic indicator.