Generators of reactive oxygen forms gamma-irradiation and ascorbic acid--cobalt metallocomplexes induced large-scale fragmentation and reparation of DNA in tumor cells.

A I Medvedev, V V Leschenko

Index: Bull. Exp. Biol. Med. 145(5) , 600-3, (2008)

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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.