A 60-kDa glucosamine binding lectin, white kidney bean lectin (WKBL), was 
purified from Phaseolus vulgaris cv. white kidney beans, by application of anion 
exchange chromatography on Q-Sepharose, affinity chromatography on Affi-gel blue 
gel, and FPLC-size exclusion on Superdex 75. The anti-proliferative activity of 
WKBL on HONE1 cells and HepG2 cells was stronger than the activity on MCF7 cells 
and WRL68 cells (IC50 values for a 48-h treatment with WKBL on HONE1 cells: 18.8 
μM; HepG2 cells: 19.7 μM; MCF7 cells: 26.9 μM; and WRL68 cells: >80 μM). The 
activity could be reduced by addition of glucosamine, which occupies the binding 
sites of WKBL, indicating that carbohydrate binding is crucial for the activity. 
Annexin V-FITC and PI staining, JC-1 staining and Hoechst 33342 staining 
revealed that apoptosis was induced on WKBL-treated HONE1 cells and HepG2 cells, 
but not as obviously on MCF7 cells. Cell cycle analysis also showed a slight 
cell cycle arrest on HONE1 cells after WKBL treatment. Western blotting 
suggested that WKBL induced apoptosis of HONE1 cells occurred through the 
extrinsic apoptosis pathway, with detection of increased level of active caspase 
3, 8 and 9.