Effect of DNA Repair Inhibitors and Iron on the Chromosome Aberration Induced by Bleomycin and Hydrogen Peroxide in CHO Cells

DNA 회복합성저해제 및 철이 Bleomycin과 과산화수소에 의해 유발된 CHO 세포의 염색체 이상빈도에 미치는 영향

The cellular toxicity and antitumor effects of bleomycin are thought to be occurred by formation of O$_2$-Fe$^{2+}$-bleomycin complexes that degrade DNA and release O$_2^-$ and $^{\cdot}$OH radicals. Hydroxyl radicals derived from hydrogen peroxide seem most likely to be involved in the various stages of carcinogenesis, and transition metals such as iron play a central role in activation of bleomycin and in formation of hydroxyl radicals. This study was performed to investigate whether treatment with ferrous sulfate increase chromosome aberration induced by bleomycin and hydrogen peroxide, and whether there is different repair mechanism for DNA damage induced by those chemicals. Treatment with 3AB, Ara C, during G$_1$ and post-treatment with caffeine, and Hu during G$_2$ increased the frequency of chromosome aberration induced by bleomycin but post-treatment with caffeine only did function that way when hydrogen peroxide was treated. When 6.6X 10$^{-7}$ M of bleomycin or 5.0X10$^{-5}$M of hydrogen peroxide were treated simultaneously with iron, the frequency of chromosome aberration was reduced, if compared with the results by bleomycin or hydrogen per oxide alone.