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Isoflavones in soy flour diet have different effects on whole‐genome expression patterns than purified isoflavone mix in human MCF‐7 breast tumors in ovariectomized athymic nude mice
Author(s) -
Liu Yunxian,
HilakiviClarke Leena,
Zhang Yukun,
Wang Xiao,
Pan YuanXiang,
Xuan Jianhua,
Fleck Stefanie C.,
Doerge Daniel R.,
Helferich William G.
Publication year - 2015
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.201500028
Subject(s) - isoflavones , genistein , ovariectomized rat , oncogene , biology , cancer research , endocrinology , medicine , estrogen , cancer , cell cycle
Scope Soy flour diet (MS) prevented isoflavones from stimulating MCF‐7 tumor growth in athymic nude mice, indicating that other bioactive compounds in soy can negate the estrogenic properties of isoflavones. The underlying signal transduction pathways to explain the protective effects of soy flour consumption were studied here. Methods and results Ovariectomized athymic nude mice inoculated with MCF‐7 human breast cancer cells were fed either Soy flour diet (MS) or purified isoflavone mix diet (MI), both with equivalent amounts of genistein. Positive controls received estradiol pellets and negative controls received sham pellets. GeneChip Human Genome U133 Plus 2.0 Array platform was used to evaluate gene expressions, and results were analyzed using bioinformatics approaches. Tumors in MS‐fed mice exhibited higher expression of tumor growth suppressing genes ATP2A3 and BLNK and lower expression of oncogene MYC . Tumors in MI‐fed mice expressed a higher level of oncogene MYB and a lower level of MHC‐I and MHC‐II , allowing tumor cells to escape immunosurveillance. MS‐induced gene expression alterations were predictive of prolonged survival among estrogen‐receptor‐positive breast cancer patients, whilst MI‐induced gene changes were predictive of shortened survival. Conclusion Our findings suggest that dietary soy flour affects gene expression differently than purified isoflavones, which may explain why soy foods prevent isoflavones‐induced stimulation of MCF‐7 tumor growth in athymic nude mice.