DIETARY FISH-OIL SUPPRESSES TUMOR-GROWTH AND METASTASIS OF LEWIS LUNG-CARCINOMA IN MICE

In this study we examined the influence of different polyunsaturated f atty acid (PUFA) diets on the tumor growth and metastatic disseminatio n of the well-characterized Lewis Lung Carcinoma (3LL) in C57BL/6J mic e. The tumor-bearing mice were fed ad libitum with three different die ts of 5% oil; either soybean oil (SO), which is rich in omega-6 (omega -6); perilla oil (PO), which is rich in omega-3 (omega-3) 18;3; and fi sh oil (FO), which is rich in omega-3, 20:5 and 22:6 PUFA. A significa ntly slower growth of primary tumor, lower mortality rate, and lower m etastatic spread were observed in mice fed FO. This trend was also obs erved in mice fed first with SO and after tumor inoculation transferre d to the FO diet. Indomethacin reduced significantly the metastasis gr owth in the SO-fed group, and exerted only a small effect in the FO an d PO fed counterparts, suggesting that eicosanoid derivatives of omega -6 fatty acids support the process of tumor growth. In addition, the l ong chain PUFA of fish oil, which are sensitive to oxidation, could ac t as targets for membrane perforation and eventual elimination of the proliferating tumor cells. (C) Elsevier Science Inc. 1997.