HL-60 cells treated with verteporfin and red light exhibit a drug dose-dependent increase in DNA fragmentation levels and a loss in viability.
Cells were incubated with different concentrations of verteporfin for 60 minutes at 37° C, exposed to red fluorescent light (2 J/cm2), and returned to the incubator. (A) The percentage of cells exhibiting DNA fragmentation at 3 hours after treatment was determined by PI staining and flow cytometric analysis (3 independent experiments). (B) Cell survival was assessed by the MTT colorimetric assay 24 hours after PDT. Results are given as a percentage of the absorbance value obtained with cells treated with light alone. MTT values for cells treated with light alone (100% viability) corresponded to a mean absorbance of 0.712 ± 0.215 above background values (3 independent experiments). Means with standard deviations are given.
