Natural Products and Cancer Biology Research Program: Cancer Research Center of Hawai‘i

Adrian A. Franke, PhD
	Professor (Specialist), Cancer Research Center of Hawai‘i; Graduate Faculty, Department of Food Science and Human Nutrition, College of Tropical Agriculture and Human Resources PhD (Pharmacy - Natural Products Chemistry), University of Freiburg, Germany adrian@crch.hawaii.edu

Publication list via PubMed

Intake of plant foods has been implicated in the risk reduction of chronic diseases including cancer. The identification of the phytochemicals responsible for this effect is therefore of vital interest. The research in my laboratory centers on the development of biomarkers reflecting exposure to vegetarian foods and on the pharmacokinetics of chemopreventive micronutrients. A central role in this respect plays the determination of food phytochemicals from body fluids and particularly, from tissues where pharmocodynamic events happen. In addition, I direct the Analytical Laboratory Shared Resource that provides analytical services for CRCH members of a wide array of analyses including but not limited to clinical markers (calcium, lipoproteins, CRP, glucose, lipid profiles) or anything that can be measured by ELISA based methods. Specific methods have also been developed for accurate, precise, fast, and affordable determination of caffeine metabolites, lipid-phase micronutrients (carotenoids, tocopherols), flavonoids, isoflavonoids, lignans, and other agents with phytoestrogenic effects; very recently, we also established assays for oxidized and reduced coenzyme Q10, 8-hydroxydeoxyguanosine, 5-methyldeoxycytosine, and vitamins A, C, D, and K1. Most our methods employ liquid chromatography (LC) with mass spectrometry (MS), photo-diode array (PDA), fluorescence (FL), or electrochemical detection (ECD). A major improvement of our analytical capabilities is the availability of a tandem LC/MS system awarded from NCRR/NIH in 2005 and UHPLC equipment acquired in 2008. Steroid analyses are currently being established in the picomolar range by tandem LC/MS. This instrumentation and techniques are currently applied in various dietary interventions as well as in many large-scale cross-sectional and prospective epidemiologic and other studies.

Our research showed that the most abundant dietary isoflavonoids, namely daidzein, glycitein, and genistein, occur predominantly in soy foods. Considering the evidence that populations with high soy intake experience lower breast, prostate, lung and other cancers isoflavonoids may play an important role in this context. In fact, we found that urinary isoflavone excretion rates are inversely correlated with breast cancer in a case-control study of a population in Shanghai and confirmed that recently in a prospective study of mixed ethnicities in Hawaii. We found recently that the bioavailability of isoflavonoids in children is greater than that in adults which might be connected with the cancer preventive effects of soy when intake happens early in life. In addition, we study other determinants regarding the bioavailabiliy of isoflavonoids including (but not limited to) the gut flora as changed through oral antibiotic therapy, bacterial or viral infections, and type of soy food or habitual diet consumed. Recently funded research includes exploration into metabolomics and identification of biomarkers reflecting radiation damage after computer tomography in children.