Effects of linoleic acid, eicosapentaenoic acid, and docosahexaenoic acid on the growth and metastasis of MM48 mammary tumor transplants in mice

In this study, we investigated the effects of linoleic acid (LA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) on the growth, metastasis and cell proliferation of a murine mammary tumor (MM48) transplanted into mice. We also examined the effect of these treatments on survival and tumor fatty acids. The growth of the primary tumor, number of metastatic tumors in the lung, and cell proliferation of the tumor were significantly inhibited in the EPA and DHA groups compared with the control and/or LA groups. Mice in the EPA group survived significantly longer than those in the control and LA groups, while mice in the DHA group survived longer than those in the control group. While the ratio of arachidonic acid (AA)/higher PUFAs (polyunsaturated fatty acids) in tumors correlated with tumor growth and lung metastases, the ratio of AA/LA did not. Therefore, it appears that both EPA and DHA exert their effects by competing with AA, thereby lowering the formation of AA metabolites.