Abstract: Selenized whey protein isolate (Se-WPI) was prepared by dry heating and its physicochemical properties such as organic selenium percentage, selenate stability, digestibility, and 77Se-nuclear magnetic resonance (NMR) characteristics as well as anti-prostate cancer activity were evaluated. The results showed that the content of organic selenium in Se-WPI prepared by heating at 80 ℃ for 24 h at pH 3.0 was 2.09%. According to the results of 77Se-NMR and selenate stability, selenium in Se-WPI existed in the form of selenite ester. The biological activities of WPI were improved after selenization. The digestibility of Se-WPI was significantly improved. Like sodium selenite (SS), Se-WPI also showed inhibitory activity against the proliferation of human prostate cancer cell lines LNCaP and DU145, and it could promote the apoptosis of LNCap cells in terms of the cell cycle, apoptosis and caspase-3 activity. In addition, Se-WPI could also inhibit the adhesion of cancer cells to basement membrane components. These results can provide a basis for further research on the anticancer mechanism of organic selenium compounds.

Key words: selenized whey protein isolate; human prostate cancer cell lines; anticancer activity