Mammary Gland microRNA profiling in female mice receiving flaxseed or its oil and secoisolariciresinol diglucoside components

Breast cancer is one of the most leading causes of cancer mortality in the world. A growing body of evidence demonstrates the association between flaxseed (FS) consumption and the reduction of breast cancer risk. Flaxseed (FS) is an oilseed rich in n-3 polyunsaturated fatty acids (PUFA), α-linolenic acid (ALA), in dietary phytoestrogen lignan, secoisolariciresinol diglucoside (SDG), and in fiber. Early-life exposure to FS or to its isolated components was associated with the improvement of the mammary gland (MG) morphogenesis and differentiation, and prevention of the MG carcinogenesis. Here, we investigated the effect of FS as a whole food and its isolated oil (FSO) and lignan (SDG) on the MG microRNA (miRNA) signature, in female mice at a late stage of development. We identified a diet-specific MG miRNA signature. Significantly deregulated miRNAs in response to the 3-weeks intervention were associated with breast cancer. Identified miRNAs targeted genes enriched in MG growth and development and in cancer. These miRNAs could be used as potential biomarkers for breast cancer. 4-5 weeks of age female C57BL/6 mice, were randomized into 4 groups (n=6/group) to receive: i) Basal AIN-93G, ii) 10% FS, iii) 3.67% FSO or iv) 0.15% SDG for 3 weeks. After the intervention, the mice were sacrificed and the mammary gland (4th left) was collected for total RNA extraction and miRNA profiling using Nanostring technologies. Please note that two samples ('Mammary Gland- Basel Diet-female05' and 'Mammary Gland- 3.67% Flaxseed Oil-female05') were excluded from the final analysis because less than 75% of miRNA probes had values above the background (the samples were quality-filtered). Please note that both txt files and the RCC files contain raw miRNAs data (there is no difference between them) and were included to facilitate their download/use by the scientific community.