Melatonin inhibits growth of cultured human uveal melanoma cells

The effects of melatonin on the growth of human uveal melanoma cells were studied in vitro. Three continuous uveal melanoma cell lines were tested. Cells were plated into multi-well plates. After 24 h, melatonin was added to the medium at concentrations from 0.001 to 1000 nM. Cells were collected and counted after 5 days and compared with the controls. Melatonin inhibited the growth of melanoma cells in a dose-dependent manner (0.1-10 nM) with a mean inhibition rate of 50%. The uptake of bromodeoxyuridine (BrdU) by the melanoma cells was also measured. Melatonin inhibited the uptake of BrdU of melanoma cells at concentrations of 0.1-10 nM with a mean inhibition rate of 40%. These results indicate that melatonin may offer a new treatment for metastatic uveal melanoma.