Inhibition of Caco-2 colon, MCF-7 and Hs578T breast, and DU 145 prostatic cancer cell proliferation by water-soluble black bean condensed tannins

The potential anti-angiogenic activities of water-soluble condensed tannins isolated from black beans were evaluated using HEL 299 normal human fibroblast lung cells, Caco-2 colon, MCF-7 and Hs578T breast, and DU 145 human prostatic cancer cells. Condensed tannins at 0.24-24 μM did not affect the growth of normal cells, but dose-dependently induced cancer cell death by apoptosis as shown by a concentration-dependent decrease in ATP and cell gross morphology. After 24 h exposure to Caco-2, MCF-7, Hs578T, and DU 145 cancer cells, water-soluble black bean condensed tannins at 24 μM suppressed fetal bovine serum stimulated cell migration, the secretion of matrix metalloproteinase-2 (MMP-2 or gelatinase A), matrix metalloproteinase-9 (MMP-9 or gelatinase B), and vascular endothelial growth factor VEGF165 receptor expression by the cancer cells in the conditioned media. The potential health enhancing properties of condensed tannins from black beans as inhibitors of angiogenesis is discussed.