Presence of antitumor activities in the milk collected from gossypol-treated dairy cows

Two human breast carcinoma cell lines (MCF-7, MCF-7 Adr) and a rat esophageal cancer cell line (RE-B2T) were used to evaluate the antiproliferative potential of gossypol (GP)-containing milk (GP-Milk), which was collected from Brown Swiss dairy cows treated daily with federally allowable 450 ppm of GP for 6 days. Treatment of the cultured cancer cells with GP-Milk for 24 h significantly inhibited the rates of 3H-thymidine incorporation during the ensuing 3-h period in all three tumorigenic cell lines. The inhibitory effects of GP-Milk occurred in a dose-dependent manner in all cases, but the calculated ED50 varied with cell lines. ED50 for GP-Milk was estimated at 10% for wild-type MCF-7 human breast cancer cells, 15% for multidrug-resistant MCF-7 Adr human breast cancer cells and 50% for RE-B2T rat esophageal carcinoma cells. The potential of GP-Milk as a dietary supplement for the prevention and/or treatment of human breast cancer is discussed in this paper.