Dietary fish oil suppresses tumor growth and metastasis of Lewis Lung Carcinoma in mice

Abstract In this study we examined the influence of different polyunsaturated fatty acid (PUFA) diets on the tumor growth and metastatic dissemination of the well-characterized Lewis Lung Carcinoma (3LL) in C57BL 6J mice. The tumor-bearing mice were fed ad libitum with three different diets of 5% oil; either soybean oil (SO), which is rich in omega-6 (ω-6); perilla oil (PO), which is rich in omega-3 (ω-3) 18:3; and fish oil (FO), which is rich in ω-3, 20:5 and 22:6 PUFA. A significantly slower growth of primary tumor, lower mortality rate, and lower metastatic spread were observed in mice fed FO. This trend was also observed in mice fed first with SO and after tumor inoculation transferred to the FO diet. Indomethacin reduced significantly the metastasis growth in the SO-fed group, and exerted only a small effect in the FO and PO fed counterparts, suggesting that eicosanoid derivatives of ω-6 fatty acids support the process of tumor growth. In addition, the long chain PUFA of fish oil, which are sensitive to oxidation, could act as targets for membrane perforation and eventual elimination of the proliferating tumor cells.