Key Findings:
Secoisolariciresinol diglucoside (SDG) may reduce breast cancer risk through selective estrogen receptor modulator (SERM)-like actions. This paper describes the initial results of 2 doses of SDG for effects on mammary and ovarian dysplasia and proliferation as well as biomarker gene expression in a rat model. Lignan increased from a median level of 11 nmol/L in control animals to 137 nmol/L in animals that received the high dose of SDG. A decrease in Ki-67 expression (25% reduction from a median of 5.2% to 3.9%) and in the mammary dysplasia score (from a median of 4 to 2) was shown for rats receiving SDG. The data indicated that treatment with SDG reversed the proliferative and dysplastic effects of estrogen on mammary tissue. SDG did not promote ovarian dysplasia in this model.
ABSTRACT:
Breast cancer prevention efforts are focused increasingly on potentially beneficial dietary modifications due to their ease of implementation and wide acceptance. Secoisolariciresinol diglucoside (SDG) is a lignan found in high concentration in flaxseed that may have selective estrogen receptor modulator like effects resulting in anti estrogenic activity in a high estrogen environment. In parallel with a human phase II prevention trial, female ACI rats (n D 8–10/group) received 0, 10, or 100 ppm SDG in the feed. The 100 ppm SDG treatment produced similar blood lignan levels as those observed in our human pilot study. Mammary and ovarian cancer progression were induced using local ovarian DMBA treatment and subcutaneous sustained release 17b-estradiol administered starting at 7 weeks of age. Mammary gland and ovarian tissues were collected at 3 months after initiation of treatment and examined for changes in epithelial cell proliferation (Ki-67, cell counts), histopathology, and dysplasia scores, as well as expression of selected genes involved in proliferation, estrogen signaling, and cell adhesion. Treatment with SDG normalized several biomarkers in mammary gland tissue (dysplasia, cell number, and expression of several genes) that had been altered by carcinogen. There is no indication that SDG promotes pre neoplastic progression in the ovarian epithelium. (Authors abstract)
Link to Full Text