Published online Feb 14, 2020. doi: 10.3748/wjg.v26.i6.562
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.
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.