Effects of Glyceollin on Estrogen Responsive Tissues

The glyceollins are anti-estrogenic compounds produced by soy plants when the plants are grown in stressful conditions, such as UV light, fungal infections, and low temperature. Previous work has shown that these compounds can inhibit estrogen-responsive tumor growth in vitro and in vivo, however, little is known about the effects of these compounds on other estrogenresponsive tissues in vivo. For this study we hypothesized that glyceollin had anti-estrogenic effects on gene expression on various estrogen-responsive tissues. Twelve adult ovariectomized CFW mice (Charles River) were divided into 4 groups of three mice: 1) Control, 2) 17-estradiol (E2) only, 3) Glyceollin only, and 4) Glyceollin + E2. Anxiety-like behavior was measured after 11 days of treatment. On day 12, estrogen-responsive tissues including the brain, uterus, liver, mammary gland, kidney, and adipose were harvested to be analyzed via real-time quantitative PCR to look at the effects of gene and protein expression. After these tissues were harvested, RNA was extracted and nanodrop analysis was conducted to determine the concentration and purity of RNA in the samples. cDNA was then created to conduct real-time qPCR analysis on various proteins/receptors in the harvested tissue. We expected to see primarily anti-estrogenic effects of glyceollin on gene expression; however, our results suggest that, besides opposing effects of estradiol, glyceollin also acts on pathways independently of estradiol, and its effects can be opposed by E2

Soy glyceollins regulate transcript abundance in the female mouse brain

Glyceollins (Glys), produced by soy plants in response to stress, have anti-estrogenic activity in breast and ovarian cancer cell lines in vitro and in vivo. In addition to known anti-estrogenic effects, Gly exhibits mechanisms of action not involving estrogen receptor (ER) signaling. To date, effects of Gly on gene expression in the brain are unknown. For this study, we implanted 17-β estradiol (E2) or placebo slow-release pellets into ovariectomized CFW mice followed by 11 days of exposure to Gly or vehicle i.p. injections. We then performed a microarray on total RNA extracted from whole-brain hemispheres and identified differentially expressed genes (DEGs) by a 2×2 factorial ANOVA with an false discovery rate (FDR)=0.20. In total, we identified 33 DEGs with a significant E2 main effect, 5 DEGs with a significant Gly main effect, 74 DEGs with significant Gly and E2 main effects (but no significant interaction term), and 167 DEGs with significant interaction terms. Clustering across all DEGs revealed that transcript abundances were similar between the E2+Gly and E2-only treatments. However, gene expression after Gly-only treatment was distinct from both of these treatments and was generally characterized by higher transcript abundance. Collectively, our results suggest that whether Gly acts in the brain through ER-dependent or ER-independent mechanisms depends on the target gene