Three percent dietary fish oil concentrate increased efficacy of doxorubicin against MDA-MB 231 breast cancer xenografts

Omega 3 polyunsaturated fatty acids (the type of fat found in fish oil) hav e been used to kill or slow the growth of cancer cells in culture and in an imal models and to increase the effectiveness of cancer chemotherapeutic dr ugs. An AIN-76 diet containing 5% corn oil (CO) was modified to contain 3% w/w fish oil concentrate (FOC) and 2% CO to test whether a clinically appli cable amount of FOC Is beneficial during doxorubicin (DOX) treatment of can cer xenografts in mice. Compared with the diet containing 5% CO, consumptio n of FOC increased omega 3 pollyunsaturated fatty acids and lipid peroxidat ion in tumor and liver, significantly decreased the ratio of glutathione pe roxidase activity to superoxide dismutase activity (a putative indicator of increased oxidative stress) in tumor but not in the liver, and significant ly decreased the tumor-growth rate. The decreased glutathione peroxidase:su peroxide dismutase ratio, indicating an altered redox state, in the tumor o f FOG-fed mice was significantly correlated with decreased tumor-growth rat e. Assay of the body weight change, blood cell counts, and number of micron uclei in peripheral erythrocytes indicated that the toxicity of DOX to the host mouse was not increased in mice fed FOG. Thus, a small amount of FOC i ncreased the effectiveness of DOX but did not increase the toxicity of DOX to the host mouse. These positive results justify clinical testing of POC i n conjunction with cancer chemotherapy.