Effects of high-isoflavone soy diet vs. casein protein diet and obesity on DMBA-induced mammary tumor development

  • Authors:
    • Reza Hakkak
    • Saied Shaaf
    • Chan Hee Jo
    • Stewart MacLeod
    • Soheila Korourian
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  • Published online on: November 8, 2010     https://doi.org/10.3892/ol.2010.202
  • Pages: 29-36
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Abstract

Obesity and elevated serum insulin growth factor-1 (IGF-1) level are major risk factors in the development of breast cancer. We investigated the long-term effects of high-isoflavone soy intake and obesity on 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumor development and on serum IGF-1 and binding protein (IGFBP-3) levels. Lean and obese female Zucker rats fed casein or high-isoflavone soy protein were orally gavaged at age 50 days with DMBA and sacrificed after 147 days. The majority of lean casein-fed rats (69%) developed mammary tumors compared to 50% in lean soy-fed rats (P=0.176). In the obese groups, 76% of soy-fed rats developed mammary tumors compared to 15% of obese casein-fed rats (P<0.001). At age 43 days, IGFBP-3 was increased in the lean soy-fed rats compared to the lean casein-fed rats (P<0.05). At age 99 days, soy- and obese casein-fed rats exhibited increased serum IGF-1 compared to the lean rats and this increase was maintained for the rest of the experiment (P<0.05). Obese rats fed casein exhibited increased IGFBP-3 levels (P<0.001). However, obese rats fed soy exhibited a significant decrease in IGFBP-3 levels compared to the lean soy-fed rats (P<0.001) and a significant decrease in IGFBP-3 levels compared to the obese casein-fed rats (P<0.001). At age 197 days, IGFBP-3 levels were increased in obese casein- and soy-fed rats (P<0.001). The results suggest that female Zucker rats fed casein diets are protected against DMBA-induced mammary tumors, which is not the case for those on high-isoflavone soy diet, and changes in the concentration of serum IGFBP-3 may contribute to the incidence of DMBA-induced mammary tumors.
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January-February 2011
Volume 2 Issue 1

Print ISSN: 1792-1074
Online ISSN:1792-1082

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Spandidos Publications style
Hakkak R, Shaaf S, Jo CH, MacLeod S and Korourian S: Effects of high-isoflavone soy diet vs. casein protein diet and obesity on DMBA-induced mammary tumor development. Oncol Lett 2: 29-36, 2011
APA
Hakkak, R., Shaaf, S., Jo, C.H., MacLeod, S., & Korourian, S. (2011). Effects of high-isoflavone soy diet vs. casein protein diet and obesity on DMBA-induced mammary tumor development. Oncology Letters, 2, 29-36. https://doi.org/10.3892/ol.2010.202
MLA
Hakkak, R., Shaaf, S., Jo, C. H., MacLeod, S., Korourian, S."Effects of high-isoflavone soy diet vs. casein protein diet and obesity on DMBA-induced mammary tumor development". Oncology Letters 2.1 (2011): 29-36.
Chicago
Hakkak, R., Shaaf, S., Jo, C. H., MacLeod, S., Korourian, S."Effects of high-isoflavone soy diet vs. casein protein diet and obesity on DMBA-induced mammary tumor development". Oncology Letters 2, no. 1 (2011): 29-36. https://doi.org/10.3892/ol.2010.202