Apoptosis Assay for SU-DHL Cell Lines

1.0% PI was added to the culture medium to monitor temporal changes in the incidence of cell death in the live culture condition. The PI-positive cells were imaged with an epi-fluorescence microscope equipped with a digital camera (Axio Obsever Z1, Zeiss, Germany)45 (link). Cell apoptosis was determined by flow cytometry using Annexin V-fluoroisothiocyanate (FITC)/PI double staining43 (link). SU-DHL-4 and SU-DHL-2 cells were collected, washed with binding buffer (Sigma-Aldrich, St. Louis, MO), and then incubated in working solution (100 μl binding buffer with 0.3 μl Annexin V-FITC and PI) for 15 minutes in dark.