Use of cross species genomic profiling identifies pathways and genes differentially regulated in prostate cancer cells treated with soy protein isolates or purified genistein

Background: The main purified compound from soy protein isolates is genistein, but this purified phytoestrogen fails to recapitulate all the features of the soy-based diet that is associated with lower incidence of prostate cancer. Materials and Methods: Rat and human prostate cancer cell lines were treated with either soy protein isolates or purified genistein. In vitro cell growth was correlated with the associated genomic expression profiles using cDNA arrays. The data was subsequently bioinformatically analyzed within and across species to identify common changes in expression profiles associated with the soy protein or genistein treatments. Results: Gene expression profiling and data mining noted genes specific to soy; however, biological pathways showed the same gene regulation profiles between genistein and soy. Conclusion: Genistein is likely the major contributor to the effect of soy proteins on cellular pathways; however, the expression of different genes using soy protein isolates suggests complexity in the many compounds found in whole soy protein.