Prostate cancer is the second leading cause of cancer death in American men. Epidemiological evidence indicates a decreased risk of prostate cancer with increased consumption of tomato products. Tomatoes contain a variety of carotenoids, some of which have been shown to have antioxidant and anticancer effects. Recent research has focused on the primary tomato carotenoid, lycopene, yet few studies have been conducted with the carotenoid biosynthetic precursors of lycopene, phytoene and phytofluene. We hypothesize that in addition to lycopene, phytoene and phytofluene contribute to the reduced risk of prostate cancer. It is unclear how well phytoene and phytofluene are absorbed, metabolized, and made available for use in the prostate, because phytoene and phytofluene are not commercially available. Reliable methods to produce, isolate, and analyze these carotenoids must be developed. The overall objective of this work is to optimize a tomato cell suspension culture system to biosynthesize 14C-radiolabeled phytoene and phytofluene for bioavailability, metabolism, and biodistribution studies of these carotenoids in an animal model.
The specific aims of this proposal are: 1) To utilize an in vitro tomato cell suspension culture system to produce both 14C-radiolabeled phytoene and phytofluene through the addition of a phytoene desaturase inhibitor, norflurazon, 2) To optimize the extraction and separation of 14C-radiolabeled phytoene and phytofluene from tomato cell suspension cultures, 3) To determine the bioavailability, metabolism, and biodistribution of 14C-radiolabeled phytoene and phytofluene in the F344, rat model. The outcome of this work will be the development of novel and reliable methods to produce and isolate 14C-radiolabeled phytoene and phytofluene, in addition to determining the accumulation of phytoene, phytofluene, and their metabolites in the prostate. These novel methods will provide the ability to design both an in vivo cancer prevention trial in an animal model and to develop 13C-labeled carotenoids for human metabolic work. ? ? ?
