Introduction. The focus of this study is on early lifestyle factors and their effect on mammary development during puberty and how they relate to increased breast cancer risk and disparities. At this time we do not understand what biological changes occur during pubertal mammary development which leads to a greater risk of developing cancer in later life. Identifying the molecular mechanisms that cause aberrant pubertal mammary development may lead to defined strategies to reduce breast cancer burden in later life. As our bodies use the sugars that we consume for energy they generate waste chemicals known as advanced glycation end products or AGEs for short. Significantly, low income, obesity and a sedentary lifestyle are established factors driving health disparity that also contribute to increased AGE accumulation levels in our bodies. In particular, AGE content in the Western Diet has consistently increased over the last 50 years due to increased consumption of sugar-laden and cheap processed/manufactured foods which are high in reactive AGE metabolites and can promote obesity. Methods. We use a dietary mouse model to assess impact of AGE on normal mammary development. Wild type FVB/n and RAGE null (RAGE-/-) mice are fed the respective diets from weaning until 7 (pubertal) or 12 (adult) weeks of age. Mammary glands are extracted for whole mounting and paraffin embedded for histology. Fibroblasts were isolated from mammary glands and cultured ex vivo. Transwell migration assays were performed with isolated fibroblasts and HC11 mouse mammary epithelial cells. qPCR was performed on the isolated fibroblasts to assess their activation status. Results. Early life exposures during mammary development influence the breast microenvironment to increase breast cancer risk. We show that due to an innate ability to influence the cellular matrix, dietary AGEs disrupt developmental programs during puberty and promote breast tumor growth. Through receptor for AGE (RAGE) dependent and independent mechanisms, chronic AGE consumption delayed ductal extension, increased ductal branching and caused aberrant terminal end bud (TEB) morphology. Dietary AGE activation of RAGE mediated a program of activated stroma leading to hyperplastic growth and the formation of pre-neoplastic lesions which persisted into adulthood. Importantly, AGE mediated effects remained even after diet intervention after puberty. In dietary-AGE breast tumor models, AGE mediated changes in tissue architecture and cell function were recapitulated and resulted in 3-fold increase in neoplastic growth. Through the perpetual activation of a reactive stroma, AGEs derived from diet represent a common early life exposure which can influence tumor behavior. Conclusions. A greater mechanistic understanding of the link between AGE intake during puberty and increased breast cancer risk may define novel potential strategies for lifestyle and pharmacological intervention aimed at reducing breast cancer risk and cancer disparities.

Citation Format: Callan C Frye, Bradley A Krisanits, Reid Schuster, Jaime Randise, Lourdes M Nogueira, Kristi Helke, Amanda C LaRue, David P Turner, Victoria J Findlay. Consumption of dietary AGEs during puberty and increased breast cancer risk: A link between lifestyle and cancer disparity [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C029.