Induction of caspase-dependent apoptosis in melanoma cells by the synthetic compound (E)-1-(3,4-dihydroxyphenethyl)-3-styrylurea

Recently, various phenolic acid phenethyl ureas (PAPUs) have been synthesized from phenolic acids by Curtius rearrangement for the development of more effective anti-oxidants. In this study, we examined the anti-tumor activity and cellular mechanism of the synthetic compound (E)-1-(3,4-dihydroxyphenethyl)-3-styrylurea (PAPU1) using melanoma B16/F10 and M-3 cells. Results showed that PAPU1 inhibited the cell proliferation and viability, but did not induce cytotoxic effects on primary cultured fibroblasts. PAPU1 induced apoptotic cell death rather than necrosis in melanoma cells, a result clearly proven by the shift of cells into sub-G₁ phase of the cell cycle and by the substantial increase in cells positively stained with TUNEL or Annexin V. Collectively, this study revealed that PAPU1 induced apoptosis in a caspase-dependent manner, suggesting a potential role as a cancer chemopreventive agent for melanoma cells.