Abstract
The three aminoquinone compounds, 2-amino-1, 4-naphthoquinone imine (ANQI), 2, 5-diamino-1, 4-naphthoquinone imine (DANQI) and 2-hydroxyamino-1, 4-naphthoquinone (HANQ), which had been reported to interact with deoxyribonucleic acid (DNA) in vitro and to inhibit DNA synthesis in Ehrlich ascites carcinoma cells, caused strand breaks in DNA of the carcinoma cells. ANQI and DANQI, when incubated with the carcinoma cells, induced the single strand breaks producing the fragments of homogeneous size. These two aminoquinones, however, did not cause the strand breaks in the carcinoma DNA when i.p. injected into the carcinoma-bearing mice. HANQ, on the other hand, induced both the single and double strand breaks in the DNA when applied on either the cells or the carcinoma-bearing mice. Since both types of the breaks occurred at the same concentration or dose of HANQ, the double strand scission might be its dominant action. From these results, the relationship between the strand scission and the inhibition of the DNA synthesis or the antitumor activity was discussed.
