Effect of melatonin on the cytotoxicity of chemotherapeutic drugs in human leukemia cells.

BACKGROUND/AIM: Limited data are available on the effect of melatonin (MLT) on the cytotoxicity of chemotherapeutic drugs in tumor cells. In this study, we aimed to evaluate the effect of MLT on the cytotoxicity of different chemotherapeutic agents in leukemia cells in vitro. MATERIALS AND METHODS: The experiments were carried out using human leukemia cell lines, Jurkat, MOLT-4, Daudi, HL-60, CMK, and K562, and two patient samples. Leukemia cells were incubated with cytarabine, daunorubicin, and etoposide with or without 10(-5) M and 10(-3) M concentrations of MLT. Cytotoxicity was measured by detecting apoptosis using flow cytometry. RESULTS: Overall, co-incubation with melatonin did not alter the cytotoxicity of chemotherapeutic drugs in cell lines and patient samples except one. In a patient sample with acute myeloid leukemia, etoposide treatment in combination either concentrations of MLT resulted in increased elimination of the leukemia cells. CONCLUSION: Melatonin does not interfere with the cytotoxic effect of cytarabine, daunorubicin and etoposide in leukemia cells.