title: Melatonin induces apoptosis in human neuroblastoma cancer cells.
abstract: Low concentrations (nanomolar) of melatonin had been previously shown to inhibit cell proliferation in several cancer cell lines as well as in experimental animal models. Additionally, cell growth inhibition and differentiation of prostate cancer cell lines by high concentrations (micromolar to millimolar) of melatonin have been recently reported. In the present paper, we show the induction of apoptosis by high doses of melatonin in the human neuroblastoma cell line SK-N-MC. We found accumulation of cells in the G2/M cell cycle phase and induction of cellular death, measured as lactate dehydrogenase (LDH) released into the culture medium, under millimolar concentration of melatonin. Apoptosis was evaluated using 4,6-diamidino-2-phenylindole staining, DNA gel electrophoresis, electron microscopy, and annexin V binding. Apoptosis progressed through the classical pathway, which involves caspase-3 activation. Cell death was dose and time-dependent; the lowest effective concentration of melatonin was 100 microm. Treatment with 1 mm melatonin for 6 days induced cell death in 75% of the cells. This novel finding shows that a nontoxic natural indoleamine may be potential therapy for some types of human neuroblastomas.
authors.affiliation: Departamento de Morfología y Biología Celular, Facultad de Medicina de la Universidad de Oviedo, Oviedo, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: García-Santos
authors.forename: Isaac
authors.initials: I
authors.lastname: Antolín
authors.forename: Federico
authors.initials: F
authors.lastname: Herrera
authors.forename: Vanesa
authors.initials: V
authors.lastname: Martín
authors.forename: Jezabel
authors.initials: J
authors.lastname: Rodriguez-Blanco
authors.forename: Maria
authors.initials: M
authors.lastname: del Pilar Carrera
authors.forename: Carmen
authors.initials: C
authors.lastname: Rodriguez
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D053938:DNA Fragmentation; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology*; D015398:Signal Transduction
chemical_list: D007770:L-Lactate Dehydrogenase; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D008550:Melatonin