Apoptosis of HL-60 cells induced by extracts from Narcissus tazetta var. chinensis

Narcissus tazetta var. chinensis is one member of the Amaryllidaceae family. We found that extracts from N. tazetta var. chinensis (ENT) strongly decreased the survival rate of the following tumor cell lines: HL-60, K562, KT1/A3, and A3R. The cytotoxic effects of ENT on non-cancer cells lines (NHBE and NIH3T3) were smaller than on leukemia cell lines. AO/EB staining and flow cytometry assays showed that ENT induced HL-60 cell apoptosis. Furthermore, the release of cytochrome c and the increase of caspase-8, -9, and -3 activities were tested after HL-60 cells were treated with ENT, which indicated that the mitochondrial pathway and cell death receptor pathway were both involved in the apoptosis signal pathways induced by ENT. Upregulation of Bax showed that the Bcl-2 family was involved in the control of apoptosis. Our results suggest that apoptosis activity can be mediated by ENT in HL-60 cells.