The effect of dietary genistein on breast cancer metastasis

The dietary isoflavone supplements are now perceived as safe and a natural alternative to hormone replacement therapy (HRT) and are recently being consumed by postmenopausal women. However, as weak estrogens, isoflavones may have the potential to alter breast cancer (BC) growth and metastasis which is also more common in the postmenopausal age group. In this study, we investigated the role of the main soy isoflavone, genistein, on the metastasis of 4T1 murine BC cells implanted in ovariectomized (OVX) BALB/c mice (OVX mice mimic the postmenopausal age group). I hypothesized that weakly estrogenic genistein will enhance BC metastasis based on our previous studies. This study was conducted in two treatment groups: control group consisting of animals on the AIN-93G control diet and genistein group consisting of animals on the control diet + 750ppm genistein; which can provide physiologically relevant plasma concentrations to what is observed in humans consuming isoflavone-containing diets. In this thesis, three investigations were conducted: 1) to apply bioluminescence imaging (BLI) techniques to monitor the tumor progression in vivo of the two dietary groups; 2) to determine the effect of genistein on the tumor burden of the India ink-stained lungs, one of the common metastatic sites; 3) to evaluate the effect of genistein supplementation on overall tumor colonies and tumor areas of both macro- and micro- metastases in the lung samples with Hematoxylin and Eosin (H and E) staining. We demonstrated that 750ppm dietary genistein did not promote BC metastasis to the lungs in BLI compared to the control group. No significant difference in lung tumor burden was observed between the two groups with India ink and H and E staining techniques. In conclusion, this appropriate preclinical postmenopausal animal model and the BLI system allow us to investigate the impact of genistein on BC metastasis under low plasma estradiol concentrations environment. Results from this study suggest that consumption of products containing genistein in a physiologically relevant level of a soy diet did not show any effect on breast tumor metastasis in vivo.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Food Science & Human Nutrition

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2010

Author dc:creator

• Fung, Chung Yan

Contributors dc:contributor

• Helferich, William G.

• Genistein
• Breast cancer metastasis
• Postmenopausal women
• Bioluminescence imaging
• 4T1 cells
• India ink staining
• Tail vein injection

Statement dc:rights

• Copyright 2010 Chung Yan Fung

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/16167

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/16167