All cancers are characterized by changes in regulators of cell proliferation and apoptosis, with many of those changes resulting from epigenetic modifications to genes involved in those pathways.  Epigenetic alterations occurring during pregnancy are known to influence the health of the offspring.  Therefore, the question of whether maternal exposure to beneficial diets that resulted in desirable epigenomes could prevent breast cancer was posed by Li and colleagues.  They report the results of a preclinical study that addressed this question in the January 2021 issue of The Journal of Nutrition.

FIGURE 1 Schematic representation of study design. Female HER2/neu transgenic mice were treated with control, BSp, GTPs, or BSp + GTPs from dams’ conception through pups’ age of 29 wk. Pups’ mammary tumor growth was monitored weekly from weaning through the end of the experiment. Dams were mated at 10 wk of age; pups were weaned at 3 wk of age; the experiment was terminated with sampling at 29 wk of age. BSp, broccoli sprouts; GTP, green tea polyphenol.

A spontaneous model of breast cancer (HER2/neu transgenic mice) was used (n=40) and the female mice were assigned to a control group, or one receiving 26% broccoli sprouts (BSp) in the food, 0.5% green tea polyphenols (GTP) in the water, or a combination of BSp and GTP.  The treatments started at conception and continued until samples were collected when the pups were 29 weeks of age. 

Tumor incidence was decreased by BSp and GTP and the combined BSp/GTP treatment reduced tumor volume.  Expression of several genes, including P16, P53, and telomerase reverse transcriptase were affected by BSp and or GTP.  The BSp/GTP combination induced apoptosis and downregulated cyclin B1, D1, and E1 and cyclin-dependent kinase 1, 2, and 4 expression.  Expression of DNA methyltransferase 1, 3A, and 3B, as well as histone deacetylase 1 were reduced by BSp and/or GTP. 

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The authors concluded that lifelong consumption of BSp and GTP could suppress estrogen receptor-negative mammary cancer by impacting cell cycle and apoptosis regulation.

References

Li S, Wu H, Tollefsbol TO.  Combined broccoli sprouts and green tea polyphenols contribute to the prevention of estrogen receptor-negative mammary cancer via cell cycle arrest and inducing apoptosis in HER2/neu mice. The Journal of Nutrition, Volume 151, Issue 1, January 2021, Pages 73–84, https://doi.org/10.1093/jn/nxaa315.

Images via canva.com.

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Nancy Turner, PhD

Nancy Turner is a Professor of Nutrition at Michigan State University.  Her research focus is on the role of diet on colon cancer and inflammatory bowel disease.  She is the author of many papers on this topic, as well as the co-editor of a book, and co-author of a textbook.