Tomatoes, lycopene, and prostate cancer: What have we learned from experimental models?

Authors: MORAN, NANCY - Children'S Nutrition Research Center (CNRC); THOMAS-AHNER, JENNIFER - The Ohio State University; WAN, LEI - The Ohio State University; ZUNIGA, KRYSTLE - University Of Illinois; ERDMAN, JOHN - University Of Illinois; CLINTON, STEVEN - The Ohio State University

Submitted to: Journal of Nutrition
Publication Type: Review Article
Publication Acceptance Date: 3/9/2022
Publication Date: 3/12/2022
Citation: Moran, N.E., Thomas-Ahner, J.M., Wan, L., Zuniga, K.E., Erdman, J.W., Clinton, S.K. 2022. Tomatoes, lycopene, and prostate cancer: What have we learned from experimental models? Journal of Nutrition. https://doi.org/10.1093/jn/nxac066.
DOI: https://doi.org/10.1093/jn/nxac066

Interpretive Summary:

Technical Abstract: Human epidemiology suggests a protective effect of tomatoes or tomato phytochemicals, such as lycopene, on prostate cancer risk. However, human epidemiology alone cannot reveal causal relationships. Laboratory animal models of prostate cancer provide opportunities to investigate hypotheses regarding dietary components in precisely controlled, experimental systems, contributing to our understanding of diet and cancer risk relationships. We review the published studies evaluating the impact of tomatoes and/or lycopene in pre-clinical models of prostate carcinogenesis and tumorigenesis. The feeding of tomatoes or tomato components demonstrates anti-prostate cancer activity in both transplantable xenograft models of tumorigenesis and models of chemically- and genetically-driven carcinogenesis. Feeding pure lycopene shows anti-cancer activity in most studies, although outcomes vary by model system, suggesting that the impact of pure lycopene may depend on dose, duration, and specific carcinogenic processes represented in different models. Nonetheless, studies with the transgenic adenocarcinoma of the mouse prostate (TRAMP) model of carcinogenesis typically demonstrate similar bioactivity to that of tomato feeding. In general, interventions that commence earlier in carcinogenesis and which are sustained tend to be more efficacious. Accumulated data suggests that lycopene is one, but perhaps not the only, anti-cancer bioactive compounds in tomatoes. Although it is clear that tomatoes and lycopene have anti-prostate cancer activity in rodent models, major knowledge gaps remain in understanding dose-response relationships and molecular mechanisms of action. Published and future findings from rodent studies can provide guidance for translational scientists to design and execute informative human clinical trials of prostate cancer prevention or in support of therapy.