Flaxseed reduces the pro-carcinogenic micro-environment in the ovaries of normal hens by altering the PG and oestrogen pathways in a dose-dependent manner

Abstract

The objective of this study was to find the optimum dose of flaxseed that would decrease prostaglandins and alter estrogen pathway endpoints implicated in ovarian cancer. Fifty 1.5-year-old chickens per group were fed different percentages of flaxseed (5%, 10%, 15%) for four months then sacrificed to collect blood and tissues. Levels of flaxseed lignan metabolites, Enterolactone (EL) and Enterodiol (ED), were measured in the serum, liver and ovaries by LC-MS/MS while omega-3 and 6 fatty acid levels were measured by GC. Effect of varying flaxseed doses was assessed by measuring levels of prostaglandin E2, estrogen metabolites (16-hydroxyestrone (16-OHE1), 2-hydroxyestrone (2-OHE1)) and analyzing the expression of E2 metabolizing enzymes (CYP3A4, CYP1B1, CYP1A1) and ERα in the ovaries. The ratio of omega-3 fatty acids/ omega-6 fatty acids increased with increase in flaxseed supplementation of diet corresponding to a dose dependent decrease in COX-2 protein and prostaglandin E2 levels. EL and ED increased in the liver, ovary and serum with increasing concentrations of flaxseed. Flaxseed decreased the expression of ERα in the ovary. The ratio of 2-hydroxyestrone to 16-hydroxyestrone in the serum increased significantly in the 15% flaxseed diet with a corresponding increase in CYP1A1 in the liver and a decrease in CYP3A4 in the ovary, respectively. CYP1B1 mRNA also decreased with flaxseed diet in the ovary. The 15% flaxseed supplemented diet significantly decreased inflammatory prostaglandin E2, ERα, CYP3A4, CYP1B1 and 16-OHE1 while it increased CYP1A1 and 2-OHE1, thus reducing the inflammatory and pro-carcinogenic microenvironment of the ovary.

Flaxseed and its components differentially affect estrogen targets in pre-neoplastic hen ovaries

“…All the reagents are as described in [17]. The AKT (9272S) and pAKT (4060S) antibodies were from Cell Signaling Technology, Beverly, MA.…”

“…Fatty acids were extracted from the ovary samples and levels of OM-3FAs and omega-6 fatty acids (OM-6FAs) were analyzed using gas chromatography as described previously [17, 29]. …”

“…Flaxseed and its components are beneficial in reducing symptoms of benign prostate hyperplasia [13], decreasing cholesterol levels [14] and decreasing skin sensitivity while improving skin texture [15]. We have shown that flaxseed diet causes an increase in the 2-hydroxyestradiol/16-α hydroxyestradiol metabolite ratio in urine and serum [16, 17], which has been shown to decrease the risk of developing cancer in postmenopausal women [18]. Flaxseed and its components have protective effects against a myriad of cancers including breast cancer [19–21], prostate cancer [22, 23] and melanoma [24].…”

“…In addition, E-cadherin, a marker characteristically upregulated in human epithelial ovarian cancers as well as in the hen ovarian tumor [30], is significantly downregulated in ovarian tumors from hens fed a flaxseed supplemented diet [31]. Flaxseed lignan metabolites, EL and ED, have been shown to decrease estrogen dependent receptor activation in breast cancer cells and flaxseed diet also results in decreased ERα expression in the chicken ovary[17]. This is significant because E2 increases tumor aggressiveness and it has been demonstrated that treatment with E2 resulted in increased rate of distant metastasis in the ovarian cancer xenograft mouse model [32].…”

“…[17, 26, 30, 31, 33], but it is important to determine the precise pathways targeted by the biologically active components of flaxseed that affect the expression of a wide range of cancer targets.…”