Dietary soy and tea mitigate chronic inflammation and prostate cancer via NFκB pathway in the Noble rat model

Hsu, Anna; Bruno, Richard S.; Löhr, Christiane V.; Taylor, Alan W.; Dashwood, Rodrick H.; Bray, Tammy M.; Ho, Emily

doi:10.1016/j.jnutbio.2010.04.006

« PreviousThe Journal of Nutritional Biochemistry
Volume 22, Issue 5 , Pages 502-510, May 2011

Dietary soy and tea mitigate chronic inflammation and prostate cancer via NFκB pathway in the Noble rat model☆

Anna Hsu
- Department of Nutrition and Exercise Sciences, Oregon State University, Corvallis, OR 97331, USA
Richard S. Bruno
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA
Christiane V. Löhr
- Department of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
Alan W. Taylor
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
Rodrick H. Dashwood
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA.
Tammy M. Bray
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA.
Emily Ho
- Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA.
- Corresponding author. Oregon State University, Corvallis, OR 97331, USA. Tel.: +1 541 737 9559; fax: +1 541 737 6914.

Received 10 October 2009; received in revised form 15 March 2010; accepted 13 April 2010. published online 01 September 2010.

Abstract

Chronic inflammation and nuclear factor-kappa B (NFκB) have been implicated in prostate cancer development; thus, dietary factors that inhibit NFκB may serve as effective chemo-preventative agents. Prostate cancer risk is significantly lower in Asian countries compared to the United States, which has prompted interest in the potential chemopreventative action of Asian dietary components such as soy and green tea. This study examined the effects of dietary soy and tea on NFκB activation and inflammation in vivo using a hormone-induced rat model for prostate cancer. Male Noble rats implanted with estradiol and testosterone were divided into 4 dietary groups: control, soy, tea, or soy+tea. NFκB activation and inflammatory cytokines were measured post implantation. The combination of soy and tea suppressed NFκB p50 binding activity and protein levels via induction of IκBα. Soy and tea also decreased prostate inflammatory infiltration, increased Bax/BcL2 ratio and decreased protein expression of tumor necrosis factor-alpha, interleukin (IL)-6 and IL-1β compared to control. Soy and tea attenuated prostate malignancy by decreasing prostate hyperplasia. These effects were not apparent in groups treated with soy or tea alone. The ongoing in vivo studies thus far suggest that combination of foods, such as soy and tea, may inhibit hormone-induced proinflammatory NFκB signals that contribute to prostate cancer development.

Keywords: Soy, Green tea, Inflammation, Noble rat, Prostate cancer, Nuclear factor kappa B