title: Generators of reactive oxygen forms gamma-irradiation and ascorbic acid--cobalt metallocomplexes induced large-scale fragmentation and reparation of DNA in tumor cells.
abstract: It was demonstrated that ascorbate-cobalt phthalocyanine complex produces a time-dependent nuclease effect on leukemia K-562 cells is. Catalase added to the incubation medium prevented or blocked fragmentation of cell DNA. The size of large-scale fragments formed during irradiation and exposure to the above system varied from 2200 to 30 kbp. The fragments induced by the system recombined slower than the fragments induced by g-irradiation in a dose adequate by the level of DNA damage. This effect observed previously in HEp-2 carcinoma cells exposed to the action of the B12b+C vitamin system can be explained by generation of H(2)O(2) inducing more severe damage to DNA structure than gamma-radiation due to site-specific Fenton reaction.
authors.affiliation: Laboratory of Cell Biochemistry and Bioenergetics, Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia. bezlepkin@iteb.ru
authors.forename: A I
authors.initials: AI
authors.lastname: Medvedev
authors.forename: V V
authors.initials: VV
authors.lastname: Leschenko
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D001205:Ascorbic Acid / Q000494:pharmacology; D053938:DNA Fragmentation / Q000187:drug effects* / Q000528:radiation effects*; D004260:DNA Repair / Q000187:drug effects / Q000528:radiation effects; D004273:DNA, Neoplasm / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D005720:Gamma Rays; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D020014:K562 Cells; D009942:Organometallic Compounds / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000528:radiation effects
chemical_list: D004273:DNA, Neoplasm; D007211:Indoles; D009942:Organometallic Compounds; D017382:Reactive Oxygen Species; C063633:cobalt phthalocyanine; D001205:Ascorbic Acid