2007 Annual Report 1a.Objectives (from AD-416) 1) to identify molecular targets for phytochemicals and. 2)to elucidate the molecular mechanism(s) by which cancer preventive phytochemicals regulate cellular targets in human cancer cell lines. 1b.Approach (from AD-416) The mechanisms by which these phytochemicals exert their cancer protective effect(s) remain unclear, despite intense scrutiny. We hypothesize that phytochemicals exert their cancer preventive effects through modulation of multiple molecular targets that are important in mammary carcinogenesis. Modulation of the molecular targets will allow phytochemicals to act on multiple cellular pathways to achieve their cancer preventive effects. We reason that identification of molecular targets for phytochemicals is an important first step. The current research proposal seeks to address these questions. Cell culture models will be used to identify molecular targets and elucidate mechanisms of action of phytochemicals. We will take a dual approach. One approach will examine changes in components of a specific pathway (such as steroid hormone receptors, xenobiotic metabolism, etc.). A second approach will use microarray as a gene profile tool to examine effects on multiple targets and pathways. 3.Progress Report As a first step toward understanding how phytochemicals work, Beltsville Human Nutrition Research Center scientists continue to use technology such as DNA microarrays to identify candidate molecular targets, as well as mechanisms, for phytochemicals. In FY07, BHNRC scientists examined the grape-derived cancer preventive phytochemical resveratrol’s effect on global gene expression patterns of androgen-responsive prostate cancer cells and the effect on androgen receptor (AR)-mediated gene expression. BHNRC scientists showed that the estrogen receptor (ER) and AR appear to interact with each other in prostate cancer cells and scientists are now determining whether the respective pathways are regulated by resveratrol. Additionally, BHNRC scientists are also studying whether muscadine grape extract exerts cancer cell growth inhibitory effects and, if so, whether it is mechanistically different from resveratrol. BHNRC scientists are also examining whether androgens can modulate the signaling pathway of retinoic acid, an important signaling molecule. This opens the possibility that crosstalk between phytochemical-, AR-, and retinoic acid-mediated pathways may exist. Moreover, BHNRC scientists are testing the effects of several other cancer preventive phytochemicals on inhibiting androgens, as well as their effects on estrogen-mediated pathways. These results allow for testing the hypothesis that regulation of sex hormone-mediated events is a relevant mechanism for phytochemicals when evaluated at physiologic levels. This work potentially can direct the usage of plant-derived foods in cancer preventive regimes and improve cancer preventive strategies. 4.Accomplishments Identification of Molecular Targets and Potential Mechanisms of Action of Diet-derived Phytochemicals: The current research addresses the lack of molecular and mechanistic information on efficacy of the cancer preventive phytochemicals such as resveratrol from grapes. In testing the hypothesis that phytochemicals may interact with multiple cellular pathways important in cancer development, BHNRC scientists identified novel molecular targets for phytochemicals in cells, as well as potential mechanisms of action that are related to their beneficial effects in breast and prostate cancer prevention. This work provides information for scientists in the cancer prevention field and establishes a foundation for further elucidation of cancer preventive properties of diet-derived phytochemicals. This work also addresses National Program 107 Action Plan Component 5, "Health Promoting Properties of Plant and Animal Foods", and Component 6, "Prevention of Obesity and Disease: Relationship between Diet, Genetics, and Lifestyle." 5.Significant Activities that Support Special Target Populations None 6.Technology Transfer Number of non-peer reviewed presentations and proceedings 5 Review Publications Lavigne, J.A., Takahashi, Y., Chandramouli, G.V., Liu, H., Shih, J., Perkins, S.N., Hursting, S.D., Barrett, J., Wang, T.T. 2007. Concentration-dependent effects of genistein on global gene expression in MCF-7 breast cancer cells: an oligo microarray study. Breast Cancer Research and Treatment. [DOI 10.1007/s10549-007-9705-6]. Trasino, S.E., Harrison, E.H., Wang, T.T. 2007. Androgen regulation of aldehyde dehydrogenase 1A3 (ALDH1A3) in androgen responsive human prostate cancer cell LNCaP. Experimental Biology and Medicine (Maywood). 232(6):762-771. Takahashi, Y., Hursting, S.D., Perkins, S.N., Wang, T.T. 2007. 17beta-estradiol differentially regulates androgen-responsive genes through an estrogen receptor-beta-dependent pathway in lncap human prostate cancer cells. Molecular Carcinogenesis. E-publication. 46(2):117-129. Takahashi, Y., Lavigne, J.A., Hursting, S.D., Chandramouli, G.V., Perkins, S.N., Kim, Y.S., Wang, T.T. 2006. Molecular signatures of soy-derived phytochemicals in androgen-responsive prostate cancer cells: a comparison study using dna microarray. Molecular Carcinogenesis. 12:943-956.