Highly Purified Eicosapentaenoic Acid as Free Fatty Acids Strongly Suppresses Polyps in ApcMin / þ Mice

Purpose: Although cyclooxygenase (COX)-2 inhibitors could represent the most effective chemopreventive tool against colorectal cancer (CRC), their use in clinical practice is hampered by cardiovascular side effects. Consumption of w-3-polyunsaturated fatty acids (w-3-PUFAs) is associated with a reduced risk of CRC. Therefore, in this study, we assessed the efficacy of a novel 99% pure preparation of w-3-PUFA eicosapentaenoic acid as free fatty acids (EPA-FFA) on polyps in ApcMin/þ mice. Experimental design: ApcMin/þ and corresponding wild-type mice were fed control diet (Ctrl) or diets containing either EPA-FFA 2.5% or 5%, for 12 weeks while monitoring food intake and body weight. Results: We found that both EPA-FFA diets protected from the cachexia observed among ApcMin/þ animals fed Ctrl diet (P < 0.0054), without toxic effect, in conjunction with a significant decrease in lipid peroxidation in the treated arms. Moreover, both EPA-FFA diets dramatically suppressed polyp number (by 71.5%and78.6%, respectively;P<0.0001) and load (by 82.5%and93.4%, respectively;P<0.0001) inboth small intestine and colon. In addition, polyps less than 1mm in size were predominantly found in the EPAFFA5%armwhereas those1 to3mmin sizeweremore frequent in theCtrl arm(P<0.0001). Interestingly, in the EPA-FFA groups, mucosal arachidonic acid was replaced by EPA (P < 0.0001), leading to a significant reduction in COX-2 expression and b-catenin nuclear translocation. Moreover, in the EPA-FFA arms, we found a significant decrease in proliferation throughout the intestine together with an increase in apoptosis. Conclusions: Our data make 99% pure EPA-FFA an excellent candidate for CRC chemoprevention. Clin Cancer Res; 16(23); 5703–11. 2010 AACR. Colorectal cancer (CRC) is the fourth commonest cancer in the United States and Western countries, with a global incidence of 1 million cases every year, and mortality of 500,000 (1). An important strategy for the prevention of CRC could involve pharmacologic interference with the multistep carcinogenesis at an initial stage of tumor development (2). Although cyclooxygenase-2 (COX-2) inhibitors still represent an effective chemopreventive tool against CRC, their use in clinical practice is hampered by cardiovascular and gastrointestinal side effects (3–5). The role of diet in modulating CRC risk is a wellaccepted concept, and natural compounds which have been proven safe over time and easily accessible through the diet represent ideal candidates as chemopreventive agents. The consumption of w-3-polyunsaturated fatty acids (w-3-PUFAs) has been associated with a reduced risk of CRC (6). One hypothesis is that their antineoplastic effects would involve the incorporation of w-3PUFAs into cellular membranes replacing the w-6-PUFA arachidonic acid (AA) with a consequent reduction of pro-inflammatory mediators (7). In particular, w-3-PUFAs produce a growth inhibitory effect in colon cancer cells and animal models (8). In clinical studies, dietary supplementation with w-3-PUFAs significantly reduces crypt proliferation and increases mucosal apoptosis (9). w-3-PUFAs include the essential Authors' Affiliations: Department of Internal Medicine, Baylor Research Institute and Sammons Cancer Center, Baylor University Medical Center, Dallas, Texas; Department of Internal Medicine, Catholic University of Sacred Heart, Rome, Center for Applied Biomedical Research (CRBA), and Clinical Department of Radiological and Histopathological Sciences, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy; Institute for Health Care Research and Improvement, Baylor Health Care System, Baylor University Medical Center, Dallas, Texas; Gastroenterology Unit, Division of Endocrinology, Department of Clinical Medicine, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Department of Nutrition Science, Second University of Naples, Naples, Italy; and Department of Pathology, VA Medical Center, Dallas, Texas Note: Supplementary data for this article are available at Clinical Cancer Research Online (http://clincancerres.aacrjournals.org/). L. Fini and G. Piazzi equally contributed to this work. Authors' Contributions: L. Fini and G. Piazzi—acquisition, analysis, and interpretation of the data, drafting of the manuscript; C. Ceccarelli, G. Graziani, V. Fogliano, and M. Selgrad—analysis and interpretation of the data, and technical support; Y. Daoud—statistical analysis, analysis and interpretationof thedata;A.Belluzzi—acquisition of the data, critical revision of the manuscript for important intellectual content; A. Munarini—technical and material support; M. Garcia—technical and material support; A. Gasbarrini andR.M. Genta–analysis and interpretationof thedata;C.R. Boland— analysis and interpretation of the data, critical revision of the manuscript for important intellectual content, and obtained funding; and L. Ricciardiello— study concept and design, analysis and interpretation of data, drafting of the manuscript, obtained funding, and study supervision. Corresponding Author: Luigi Ricciardiello, Dipartimento di Medicina Clinica, Universita’ degli studi di Bologna, Via Massarenti 9, Bologna 40138, Italy. E-mail: luigi.ricciardiello@unibo.it doi: 10.1158/1078-0432.CCR-10-199