Published online Feb 15, 2020. doi: 10.4251/wjgo.v12.i2.149
Peer-review started: September 12, 2019
First decision: October 14, 2019
Revised: October 25, 2019
Accepted: November 13, 2019
Article in press: November 13, 2019
Published online: February 15, 2020
Processing time: 155 Days and 23.2 Hours
Caffeine is a purine alkaloid and is widely consumed in coffee, soda, tea, chocolate and energy drinks. To date, a growing number of studies have indicated that caffeine is associated with many diseases including colorectal cancer. Caffeine exerts its biological activity through binding to adenosine receptors, inhibiting phosphodiesterases, sensitizing calcium channels, antagonizing gamma-aminobutyric acid receptors and stimulating adrenal hormones. Some studies have indicated that caffeine can interact with signaling pathways such as transforming growth factor β, phosphoinositide-3-kinase/AKT/mammalian target of rapamycin and mitogen-activated protein kinase pathways through which caffeine can play an important role in colorectal cancer pathogenesis, metastasis and prognosis. Moreover, caffeine can act as a general antioxidant that protects cells from oxidative stress and also as a regulatory factor of the cell cycle that modulates the DNA repair system. Additionally, as for intestinal homeostasis, through the interaction with receptors and cytokines, caffeine can modulate the immune system mediating its effects on T lymphocytes, B lymphocytes, natural killer cells and macrophages. Furthermore, caffeine can not only directly inhibit species in the gut microbiome, such as Escherichia coli and Candida albicans but also can indirectly exert inhibition by increasing the effects of other antimicrobial drugs. This review summarizes the association between colorectal cancer and caffeine that is being currently studied.
Core tip: Increasing evidence indicates that caffeine has wide-ranging effects on pathogenesis, metastasis and prognosis of colorectal cancer. This study systematically reviewed the literature on the targets and effects of caffeine on colorectal cancer. The effects were categorized into five groups: (1) communicating with cell signaling; (2) modulating immune response; (3) influencing gut bacteria; (4) regulating cell cycle; and (5) redox homeostasis.