The aim of the present study was to compare the effect of
realgar nanoparticles and
arsenic trioxide (ATO) on viability, DNA damage, proliferation, autophagy and apoptosis in the human
melanoma cell lines BOWES and A375. The application of various flow cytometric methods for measurements cell viability,
DNA cell cycle, mitochondrial potential, lysosomal activity, and intracellular content of
glutathione was used. In addition, quantitative PCR, western blotting and multiplex bead array analyses were applied for evaluation of redox stress, autophagic flux, and cell signaling alterations.The results showed that
realgar treatment of studied cells caused modulation of cell proliferation, induced a block in G2/M phase of the cell cycle and altered phosphorylation of IκB, Akt, ERK1/2, p38, and JNK
kinases, as well as decreased mitochondrial membrane potential. Additionally, it appeared that induction of cell death by both
realgar and ATO was dose-dependent, when lower (0.3 µM) dosage increased lysosomal activity and induced autophagy and higher (1.25 µM) concentration resulted in the appearance of apoptosis, while pan-
caspase inhibitor attenuated more efficiently
realgar- than ATO-induced cell death. Furthermore, low concentrations of ATO and
realgar nanoparticles increased the content of intracellular
glutathione and elevated γ-H2AX expression confirmed DNA damage preferentially at higher concentrations of both drugs used. Further analysis revealed slight differences in time-dependent phosphorylation pattern due to both
realgar and ATO treatments, while significant differences were noticed between cell lines. In conclusion,
realgar nanoparticles and ATO treatment induced dose-dependent activation of autophagy and apoptosis in both
melanoma cell lines, when autophagy flux was determined at lower
drug concentrations and the switch to apoptosis occurred at higher concentrations of both
arsenic forms.