Melatonin is an
indolamine that is synthesized in the pineal gland and shows a wide range of physiological functions. Although the anti-aging properties of
melatonin have been reported in a senescence-accelerated mouse model, whether
melatonin modulates cellular senescence has not been determined. In this study, we examined the effect of
melatonin on anticancer
drug-induced cellular premature senescence. We found that the
doxorubicin (DOX)-induced senescence of A549 human
lung cancer cells and IMR90 normal lung cells was substantially inhibited by cotreatment with
melatonin in a dose-dependent manner. Mechanistically, the DOX-induced G2/M phase cell cycle arrest and the decrease in cyclinB and cdc2 expression were not affected by
melatonin. However, the DOX-induced increase in intracellular levels of ROS, which is necessary for premature senescence, was completely abolished upon
melatonin cotreatment. In addition, the reduction in mitochondrial membrane potential that occurs upon DOX treatment was inhibited by
melatonin. An aberrant increase in mitochondrial respiration was also significantly suppressed by
melatonin, indicating that
melatonin ameliorates the
mitochondrial dysfunction induced by DOX treatment. The treatment of A549 cells with
luzindole, a potent inhibitor of
melatonin receptors, failed to prevent the effects of
melatonin treatment on mitochondrial functions and premature senescence in cells also treated with DOX; this suggests that
melatonin suppresses DOX-induced senescence in a
melatonin receptor-independent manner. Together, these results reveal that
melatonin has an inhibitory effect of
melatonin on premature senescence at the cellular level and that
melatonin protects A549 cells from DOX-induced senescence. Thus,
melatonin might have the therapeutic potential to prevent the side effects of anticancer
drug therapy.