Combinatorial dietary approaches to prevent highly fatal estrogen receptor-negative [ER(-)] breast cancer (BC) can offer many advantages over single-agent approaches, most notably the potential for greater efficacy without increased risk of toxicity. We have shown that combined green tea polyphenols that inhibit DNA methyltransferases and sulforaphane in broccoli sprouts that inhibits histone deacetylases can significantly delay ER(-) BC initiation and impede its progression at practical and safe dietary levels. Our results have also shown that the epigenetic machinery is mechanistically important to the efficacy of ER(-) BC prevention by these diets. Maternal or paternal consumption of this combinatorial regimen can lead to increased latency and reduced tumor growth in ER(-) BC offspring that have consumed a control diet. Our field-driving studies show for the first time that this combinatorial diet impacts the epigenome and gene expression of gametes strongly supporting transgenerational epigenetic effects. Our hypothesis is that combinatorial green tea polyphenols and sulforaphane-enriched broccoli sprout diets can extend their epigenetic-neutralizing ER(-) BC preventive effects from one generation to another either through transplacental effects or through transgenerational effects. These studies will be important to resolving the generational efficacy of combinatorial cancer prevention and the epigenetic mechanisms through which this effect is mediated. Since our preliminary findings have indicated that consumption of this combinatorial diet can operate through the paternal as well as maternal lineage to prevent ER(-) BC in control-fed female offspring, this strongly suggests that the gametogenic epigenetic changes we have discovered have mechanistic importance for transgenerational effects in addition to transplacental effects in mothers fed this combinatorial diet. The paternal effects on epigenetic control of key tumor-related genes by this combinatorial epigenetic-modulating diet will contribute significantly to elucidation of the mechanisms through which this diet confers preventive effects on ER(-) BC. One of the goals of this proposed innovative investigation is to resolve the generational ER(-) BC cancer preventive impact of combinatorial epigenetic-modulating green tea polyphenols and sulforaphane-enriched broccoli sprouts and the epigenetic and epigenomic mechanisms responsible for their efficacy. This proposed investigation will have considerable impact in that the consumption of a combined epigenetic-modulating diet by either the mother or father to delay and reduce ER(-) BC in their offspring would have broad implications for new perspectives for cancer prevention. Further, ER(-) BC is often recalcitrant to conventional modes of cancer therapy which significantly increases the importance of means to facilitate its prevention. Novel approaches to reducing the risk of ER(-) BC through maternal and/or paternal consumption of this combinatorial diet would contribute significantly to enhanced ER(-) BC prevention and perhaps preventive control of other cancers worldwide.

Public Health Relevance Statement: Estrogen receptor-negative breast cancer is too often fatal and there is a strong need to prevent this disease before it becomes recalcitrant to conventional cancer therapy. An important field-driving and novel goal of this application is to develop dietary combinations of green tea polyphenols and sulforaphane-rich broccoli sprouts that can be safely consumed to reduce estrogen receptor-negative breast cancer risk and severity in offspring generations even when consumed by either of their parents before conception of the offspring.