Growth of human lung adenocarcinoma in nude mice is influenced by various types of dietary fat and vitamin E

Studies have shown effects of dietary lipids on carcinogenesis and tumour p rogression. Different mechanisms for the inhibitory effect of n-3 fatty aci ds (FA) have been: proposed. The inhibition of the growth of subcutaneously transplanted A427 lung adenocarcinoma cells in athymic nude mice may occur due to an increased level of lipid peroxidation products and is the object of this study. The nude mice were fed diets supplemented with corn oil (CO ) olive oil (OO) or K85, a: mixture of ethyl esters of n-3 FAs, mainly eico sapentaenoic acid (EPA, 20:5, n-3) and docosahexaenoic acid (DHA, 22:6, n-3 ). Tumours of the n-3 FA group showed reduced growth. Peroxidation products measured by the thiobarbituric acid reactive substances (TBARS) test showe d higher levels in tumours from n-3 FA fed mice than in the other diet grou ps. The growth inhibitory effects and the elevated level of TBARS in the n- 3 FA diet group were counteracted by vitamin E supplement in the diet. Cu/Z n-superoxide dismutase (SOD) activity in liver did not differ greatly among the diet groups. The Ki-67 labelling index (LI), indicating cell prolifera tion rate was significantly lower in the K85 diet group compared to the oth er diet groups.