title: Ascorbic acid enhances radiation-induced apoptosis in an HL60 human leukemia cell line.
abstract: This study was conducted to examine the utility of the combined use of ascorbic acid (AsA) and radiation in clinical applications. We investigated cell survival, DNA fragmentation, and caspase activation after X-ray irradiation and AsA treatment of human leukemia HL60 cells. The number of living cells decreased after combined X-ray irradiation and AsA treatment (2 Gy + 5 mM) in comparison with that after X-ray irradiation (2 Gy) or AsA treatment (5 mM) alone. DNA fragmentation was more in the cells subjected to combined X-ray irradiation and AsA treatment than in those subjected to X-ray irradiation alone. Caspase-3, caspase-8, and caspase-9 were highly activated following combined X-ray irradiation and AsA treatment, but caspase-8 activity was not markedly increased after X-ray irradiation alone. Bax levels in the mitochondrial membrane fractions were increased after AsA treatment alone and after combined X-ray irradiation and AsA treatment. However, there was no apparent increase in the Bax levels after X-ray irradiation treatment alone. Thus, this study confirmed that supplementing X-ray irradiation with AsA treatment results in increased apoptosis in HL60 cells. With regard to the apoptosis-inducing factors, we hypothesized that Bax and caspase-8 were activated after combined X-ray irradiation and AsA treatment compared with either treatment alone.
authors.affiliation: Division of Oral and Maxillofacial Radiology, Department of Human Biology and Pathophysiology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Shinozaki
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Hosokawa
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Hazawa
authors.forename: Ikuo
authors.initials: I
authors.lastname: Kashiwakura
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Okumura
authors.forename: Tohru
authors.initials: T
authors.lastname: Kaku
authors.forename: Eiji
authors.initials: E
authors.lastname: Nakayama
mesh_terms: D017209:Apoptosis; D001205:Ascorbic Acid / Q000494:pharmacology*; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival; D053938:DNA Fragmentation; D018922:HL-60 Cells; D006801:Humans; D007938:Leukemia / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D008928:Mitochondria / Q000378:metabolism; D013997:Time Factors; D014965:X-Rays; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: C494826:BAX protein, human; D051028:bcl-2-Associated X Protein; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D001205:Ascorbic Acid