The Therapeutic Effects of Bromelain against Colorectal Cancer: A Systematic Review

Background: Colorectal cancer (CRC) is one of the most prevalent cancers worldwide. Objective: Considering the side effects of chemotherapy treatments, we reviewed the anti-cancer effects and mechanisms of bromelain on colon cancer cells in this study. Methods: The PRISMA guidelines were followed in the design of this systematic review. Various databases, including PubMed, Web of Science, Cochrane Library, and Scopus, were thoroughly searched. Finally, 14 articles were retrieved after considering the study's inclusion and exclusion criteria. The desired data were extracted, entered into an Excel file, and the study results were reviewed. Results: According to the included studies, bromelain can significantly reduce the survival and death of cloned cancer cells through different mechanisms. These mechanisms include impeding tumor growth and metastasis by reducing mucins production/secretion and increasing/reducing reactive oxygen species (ROS) production. Moreover, bromelain induces apoptosis via reduced expression of Bcl-2, extracellular signal-related kinase (ERK), Akt, activation caspase system (caspase-3, 7, 8, and 9), and extranuclear p53. Ferroptosis was another mechanism of causing cell death. In addition, bromelain activates the autophagy pathway, lysosome formation, and deregulation of other autophagyrelated proteins. Conclusion: Bromelain effectively inhibits colon cancer cells' growth, proliferation, and metastasis and reduces their survival by different mechanisms. Therefore, after examining clinical studies, it can be used as an effective drug for treating CRC.