Realgar Nanoparticles Induced Cytotoxicity in Promyelocytic Leukemia HL-60 Cells

Realgar, one of mineral drugs in Chinese traditional medicines has attracted an increasing attention because of its prominent anti-tumor effect. However, new challenges for improving its bioavailability has to be faced. Our previous studies have demonstrated that realgar nanoparticles may provide a less toxic agent for anti-neoplasia by suppressing angiogenesis. In the present study, we improved milling process, prepared raw realgar particles and realgar nanoparticles with the same background As₂O₃ concentrations and compared their cytoxicity to promyelocytic leukemia HL-60 cells including inhibiting cell growth, inducing oxidative stress. It was found that treatment with realgar nanoparticles resulted in considerably low cell viability compared with raw realgar particles. On the other hand, treatment with realgar nanoparticles promoted the generations of reactive oxygen species (ROS) and inhibited the activity of catalase (CAT), which was accompanied by lipid peroxidation and protein oxidation, especially the loss of its free thiols, whereas such events was not observed in HL-60 cells exposed to raw realgar particles. These results suggest that realgar nanoparticles are superior over raw realgar particles for their cytotoxicity including inhibition of cell proliferation and enhanced effects of oxidative stress, which may provide a possibility for its application in tumor therapy