The combined use of platinum nanoparticles and hydrogen molecules induces caspase-dependent apoptosis

incubated in an atmosphere of 75%(v/v) H2/20%(v/v) O2/5%(v/v) CO2 ,7 5%(v/v) He/20%(v/v) O2/5%(v/v) CO2 atmosphere or 75%(v/v) N2/20%(v/v) O2/5%(v/v) CO2 atmosphere for 12-48 hr after incubated with Pt nps for 2 h. Untreated cultures were included as controls. Cytotoxicity was determined by cell-counter. Apoptosis pathway of HL60 cells was investigated by Sub G-1 assay. Growth suppression was not observed when cells were treated with Pt nps or H2 only. Analysis of cell cycle and activity of caspase-3 suggested that combination use of both Pt nps and H2 induced apoptosis in HL60 cells. Our caspase activity experimentation suggests that apoptosis was caused via caspase-8 activation. These results suggested that atomic hydrogen from H2 induces caspase-8 dependent apoptosis. The cytotoxicity was not detected in Pt nps or H2 separately treated cells. Apoptosis was determined only when cells were treated with both Pt nps and H2, suggesaspase-8 dependent apoptosis was caused by atomic hydrogen produced from H2 by catalyst activity of Pt nps.