Treatment with soybean-derived Bowman Birk inhibitor increases serum prostate-specific antigen concentration while suppressing growth of human prostate cancer xenografts in nude mice.

Abstract

Bowman Birk inhibitor (BBI) is an anticarcinogenic serine protease inhibitor that may inhibit the protease activity of prostate-specific antigen (PSA) and the growth of human prostate cancer xenografts in nude mice. Human prostate cancer xenografts were established by implanting LNCaP cells into the prostate glands of NCRNU-M athymic nude mice. The animals with established tumors were maintained on a control diet or diets supplemented with 1% BBI or 1%, 2%, or 3% BBI concentrate (BBIC) for 6 weeks. The serum PSA concentrations were determined before and after the BBI or BBIC treatment period. The final tumor loads were determined at autopsy. Treatment with BBI or BBIC decreased the final tumor load and increased the tumor doubling time and PSA density in the nude mice bearing human prostate cancer xenografts. BBI and/or BBIC could be useful for prostate cancer treatment.