Apoptosis induced by ultraviolet a exposure in the presence of enoxacin in HL-60 Cells

Abstract

Background: The ultraviolet A (UVA) spectrum mainly includes the region associated with the phototoxicity of fluoroquinolone antimicrobial agents. This study investigated apoptosis induced with UVA light and enoxacin in HL-60 cells. Materials and Methods: HL-60 cells were irradiated by UVA (1.1 mW/cm 2 ) for 20 min in the presence or absence of enoxacin. The induction of apoptosis was investigated by analysing cell morphology, flow cytometry of annexin V-positive cells, DNA ladder formation, and caspase-3 activation. Results: Significant induction of apoptosis, DNA fragmentation, and caspase-3 activation were observed in cells treated with both UVA and enoxacin. UVA-induced apoptosis was significantly suppressed when NaN3, a singlet oxygen scavenger, was present. Conclusion: Apoptosis was induced by the combination of UVA and enoxacin in HL-60 cells, and singlet oxygen appears to play an important role in photodynamically-induced apoptosis.