Flaxseed and its lignans inhibit estradiol-induced growth, angiogenesis, and secretion of vascular endothelial growth factor in human breast cancer xenografts in vivo.

Abstract

PURPOSE:

Vascular endothelial growth factor (VEGF) is a potent stimulator of angiogenesis, which is crucial in cancer progression. We have previously shown that estradiol (E2) increases VEGF in breast cancer. Phytoestrogens are potential compounds in breast cancer prevention and treatment by poorly understood mechanisms. The main phytoestrogens in Western diet are lignans, and flaxseed is a rich source of the mammalian lignans enterodiol and enterolactone.

EXPERIMENTAL DESIGN:

In the present study, ovariectomized mice were treated with continuous release of E2. MCF-7 tumors were established and mice were fed with basal diet or 10% flaxseed, and two groups that were fed basal diet received daily injections with enterodiol or enterolactone (15 mg/kg body weight).

RESULTS:

We show that flaxseed, enterodiol, and enterolactone counteracted E2-induced growth and angiogenesis in solid tumors. Extracellular VEGF in vivo, sampled using microdialysis, in all intervention groups was significantly decreased compared with tumors in the basal diet group. Our in vivo findings were confirmed in vitro. By adding enterodiol or enterolactone, E2-induced VEGF secretion in MCF-7 cells decreased significantly without agonistic effects. The increased VEGF secretion by E2 in MCF-7 cells increased the expression of VEGF receptor-2 in umbilical vein endothelial cells, suggesting a proangiogenic effect by E2 by two different mechanisms, both of which were inhibited by the addition of lignans.

CONCLUSIONS:

Our results suggest that flaxseed and its lignans have potent antiestrogenic effects on estrogen receptor-positive breast cancer and may prove to be beneficial in breast cancer prevention strategies in the future.

• Authors: Malin Bergman Jungeström, Lilian U Thompson, Charlotta Dabrosin
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 13 Issue 3 Pg. 1061-7 (Feb 01 2007) ISSN: 1078-0432 [Print] United States
• PMID: 17289903 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• Lignans
• Phytoestrogens
• Vascular Endothelial Growth Factor A
• Estradiol
• 2,3-bis(3'-hydroxybenzyl)butane-1,4-diol
• 4-Butyrolactone
• 2,3-bis(3'-hydroxybenzyl)butyrolactone

Topics

• 4-Butyrolactone (analogs & derivatives, metabolism)
• Animals
• Antineoplastic Agents (pharmacology)
• Breast Neoplasms (metabolism, prevention & control)
• Cell Line, Tumor
• Cell Proliferation
• Endothelium, Vascular (cytology)
• Estradiol (metabolism)
• Female
• Flax (metabolism)
• Humans
• Lignans (metabolism)
• Mice
• Neoplasm Transplantation
• Neovascularization, Pathologic
• Phytoestrogens (metabolism)
• Umbilical Veins (metabolism)
• Vascular Endothelial Growth Factor A (metabolism)