Melanoma is one of the most aggressive
skin cancers with an increasing rate of morbidity. Umbilicaria esculenta is an edible lichen and its main component of extracts-
polysaccharide (PUE) has shown significant antitumor effects in a variety of
cancer types such as stomach
adenocarcinoma. However, whether it has an anti-
melanoma effect and the underlying mechanism has not been revealed. In this article, we showed that PUE extracted from Umbilicaria esculenta could inhibit the growth of A875 and A375
melanoma cells but without obvious toxicity to normal vascular endothelial cells. The generation of
reactive oxygen species (ROS) in A875 cells was significantly elevated when treated with PUE for 24h. In addition, the expression of
caspase-3 and -9 also increased as compared to the controlled group which resulted in the apoptosis of A875
melanoma cells. In the meantime, when pre-treated with
N-acetylcysteine (NAC), the ROS scavenger, PUE induced apoptosis and cell death could be reversed via suppression of elevated generation of ROS and ROS-mediated
caspase-9 expression. In summary, our study demonstrated that PUE extracts from Umbilicaria esculenta have a potent anti-
melanoma effect through the induction of ROS and caspases-3 and -9. It could provide a promising strategy of
melanoma therapy with the components from the extracts of natural and edible plants such as lichen Umbilicaria esculenta.