Active oxygen species in DNA damage induced by carcinogenic metal compounds.

Some carcinogenic metal compounds [chromate(VI), Fe(III) nitrilotriacetate, cobalt(II), and nickel(II)[ induced formation of various oxygen radical species in the presence of hydrogen peroxide. These oxygen radicals were suggested to give different kinds of site-specific DNA damage; 8-hydroxyl-2'-deoxyguanosine formation is included in the DNA damage. Using pulsed-field gel electrophoresis, nickel sulfide was shown to induce oxidative DNA cleavage in cultured cells. On the basis of these findings, we have emphasized the role of oxygen radicals in metal carcinogenesis.