ABSTRACT Scientific Premise and Hypothesis: Chemoprevention using safe and inexpensive phytochemicals from edible or medicinal plants is appealing for reducing the death and suffering from prostate cancer, which continues to be a leading cause of cancer-linked mortality among American men. A chemopreventative intervention for prostate cancer is still lacking. Increased de novo synthesis coupled with β-oxidation of fatty acids is a rather unique and targetable mechanism of human prostate cancer. A role for upregulated de novo fatty acid synthesis in pathogenesis of prostate cancer is substantiated by studies showing overexpression of mRNA/protein levels of key fatty acid synthesis enzymes, including ATP citrate lyase (ACLY), acetyl-CoA carboxylase 1 (ACC1), and/or fatty acid synthase (FASN) in early (prostatic intraepitheilial neoplasia; PIN) as well as advanced (adenocarcinoma) disease when compared to normal tissue. In addition, genetic or pharmacological suppression of ACLY, ACC1, and FASN causes inhibition of prostate cancer cell growth in vitro and in vivo. Therefore, inhibition of synthesis and/or β-oxidation of fatty acids represents a promising strategy for chemoprevention of prostate cancer. The overall goal of this bench-cage-bedside project is to determine the feasibility of fatty acid metabolism inhibition for chemoprevention of prostate cancer using sulforaphane (SFN), which is the principal bioactive phytochemical in broccoli sprout extract (BSE). The preclinical studies are conceived to test the hypothesis that prostate cancer chemoprevention by SFN and BSE in a clinically-relevant transgenic mouse model (Hi-Myc) is associated with suppression of synthesis as well as β-oxidation of fatty acids leading to inhibition of cancer cell proliferation. A pilot double-blind, randomized, and placebo-controlled window of opportunity clinical trial in men scheduled for prostatectomy is also proposed to determine whether daily oral administration of a well-characterized BSE formulation (BroccoMax®), the safety of which has already been tested clinically, for 4 weeks leads to suppression of circulating and prostate tumor levels of fatty acids. Support for the above stated hypothesis derives from our own published and preliminary unpublished findings. Specifically, we found that SFN treatment not only suppresses protein/mRNA levels of ACC1 and FASN as well as the dehydrogenases implicated in β-oxidation of fatty acids but also decreases acetyl-CoA levels in human prostate cancer cells in vitro and prostate tumors of TRAMP mice in vivo. Acetyl-CoA is the building block of de novo fatty acid synthesis but is also generated in the mitochondria upon β-oxidation of fatty acids. Specific Aims: The well-integrated specific aims of this highly-focused application are to: (1) Determine the mechanism underlying SFN-mediated inhibition of fatty acid synthesis and β-oxidation using cellular models of prostate cancer and normal prostate cells; (2) Determine wh...