Inhibition of the in Vitro Growth of Human Mammary Carcinoma Cell Line (MCF-7) by Selenium and Vitamin E

The effects of the natural form of vitamin E; alpha - tocopherol and two forms of selenium; sodium selenite and selenomethionine on the in vitro growth of the human mammary cancer cell line; MCF-7 were investigated. Two experimental protocols were used. In the first, each of the test chemicals was included alone at various concentrations. In the second, one of the two selenium compounds was added at concentrations ranging from 1.0 x 10 – 8 M and 1.0 x 10 – 4 M in the presence of a fixed concentration of alpha - tocopherol (1.0 x 10 – 9 M, 1.0 x 10 M - 8 M, or 1.0 x 10 -7 M). In the individual treatment, high concentrations of all compounds caused statistically significant, and concentration – dependent decreases in cell viability. These depressions were in the following order: alpha - tochopherol › sodium selenite › selenomethionine. A combined dose of alpha – tocopherol and each selenium form maintained the same antiproliferative effects that were elicited by higher independent concentrations. In both protocols, a relatively higher inhibitory potency of sodium selenite over selenomethionine was obvious. Although the mechanisms of action are not well understood, several ones are discussed