TP53 and melanoma: Arnicolide D also exerts antimelanoma effects by reducing cell viability, inducing G2/M cell cycle arrest and apoptosis, increasing the levels of p53 and p21, and decreasing the levels of the G2/M checkpoint protein Cdc2 and the cell cycle protein B1, through the mechanisms of inhibiting the activity of IKKα/β, the degradation of IκBα, and the phosphorylation and expression of NF-κB p65 in melanoma cells.