Molecular basis of Fas and cytochrome c pathways of apoptosis induced by tartary buckwheat flavonoid in HL-60 cells.

Abstract

In a previous study, we showed that tartary buckwheat flavonoid (TBF) induced HL-60 leukemic cell apoptosis, most likely via a caspase 3 activating pathway. The aim of this study was to further investigate the molecular mechanisms involved in TBF-induced apoptosis of HL-60 cells. Thus, death receptor Fas expression on HL-60 cells was detected by flow cytometry (FCM). We also studied the effect of TBF on intranuclear DNA binding activity of NF-kappaB, as well as release of mitochondrial cytochrome c into the cytosol in HL-60 cells by FCM. The results suggest that TBF-induced apoptosis of HL-60 cells may be stimulated by the release of cytochrome c to the cytosol, upregulation of Fas expression on the cell surface, and through a caspase-3-dependent mechanism. Furthermore, TBF-induced apoptosis may be partly regulated through the inactivation of NF-kappaB in HL-60 cells. The induction of apoptosis by TBF may be attributed to its cancer chemopreventive activity.