Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 14, 2020; 26(6): 562-597
Published online Feb 14, 2020. doi: 10.3748/wjg.v26.i6.562
Tea polyphenols and their chemopreventive and therapeutic effects on colorectal cancer
Shi-Tong Wang, Wen-Qi Cui, Dan Pan, Min Jiang, Bing Chang, Li-Xuan Sang
Shi-Tong Wang, Department of Cardiovascular Ultrasound, First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China
Wen-Qi Cui, Department of Neurology, Shengjing Hospital, Affiliated Hospital of China Medical University, Shenyang 110004, Liaoning Province, China
Dan Pan, Li-Xuan Sang, Department of Geriatrics, First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China
Min Jiang, Bing Chang, Department of Gastroenterology, First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China
Author contributions: Wang ST and Sang LX designed the structure of the manuscript; Wang ST, Cui WQ, Pan D, Chang B and Sang LX drafted the manuscript; Wang ST, Cui WQ and Sang LX reviewed the literature; Pan D, Jiang M and Sang LX critically revised the manuscript.
Supported by the Innovative Talents Support Program of Institution of Higher Learning of Liaoning Province, No. 2018-478; and Innovative Talents of Science and Technology Support Program of Young and Middle Aged People of Shenyang, No. RC170446.
Conflict-of-interest statement: We declare no conflicts of interest.
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:
Corresponding author: Li-Xuan Sang, MD, PhD, Chief Doctor, Department of Geriatrics, First Affiliated Hospital of China Medical University, 155 Nanjing North Street, Heping District, Shenyang 110001, Liaoning Province, China.
Received: October 19, 2019
Peer-review started: October 19, 2019
First decision: December 4, 2019
Revised: December 30, 2019
Accepted: January 11, 2020
Article in press: January 14, 2020
Published online: February 14, 2020

Colorectal cancer (CRC), a multifactorial disease, is usually induced and developed through complex mechanisms, including impact of diet and lifestyle, genomic abnormalities, change of signaling pathways, inflammatory response, oxidation stress, dysbiosis, and so on. As natural polyphenolic phytochemicals that exist primarily in tea, tea polyphenols (TPs) have been shown to have many clinical applications, especially as anticancer agents. Most animal studies and epidemiological studies have demonstrated that TPs can prevent and treat CRC. TPs can inhibit the growth and metastasis of CRC by exerting the anti-inflammatory, anti-oxidative or pro-oxidative, and pro-apoptotic effects, which are achieved by modulations at multiple levels. Many experiments have demonstrated that TPs can modulate several signaling pathways in cancer cells, including the mitogen-activated protein kinase pathway, phosphatidylinositol-3 kinase/Akt pathway, Wnt/β-catenin pathway, and 67 kDa laminin receptor pathway, to inhibit proliferation and promote cell apoptosis. In addition, novel studies have also suggested that TPs can prevent the growth and metastasis of CRC by modulating the composition of gut microbiota to improve immune system and decrease inflammatory responses. Molecular pathological epidemiology, a novel multidisciplinary investigation, has made great progress on CRC, and the further molecular pathological epidemiology research should be developed in the field of TPs and CRC. This review summarizes the existing in vitro and in vivo animal and human studies and potential mechanisms to examine the effects of tea polyphenols on CRC.

Keywords: Tea polyphenols, Colorectal cancer, Gut microbiota, Signal pathway, Anti-inflammation, Mechanisms

Core tip: Colorectal cancer (CRC) has become the third most common cancer and the fourth most common cause of cancer-related death, which is involved in a series of complex mechanisms. Professors pay attention to searching for reasonable methods to prevent and treat CRC. Tea polyphenols, as natural polyphenolic phytochemicals in tea, have been demonstrated to prevent and treat CRC effectively. They may become a novel medicine applied in CRC to prevent cancer and reduce the side effects of chemotherapy medicines in the future. This review summarizes the molecular mechanism of tea polyphenols acting on CRC.