Failure of the intercalating agent 4'-(9-acridylamino)-methanesulphon-m -anisidide to induce DNA-repair replication in cultured human cells.

A search has been made for DNA-repair replication in cultured human cells treated with the DNA-intercalating agent 4'-(9-acridinylamino) methanesulphon--m-anisidide (m-AMSA). Previous reports had suggested that the transient appearance of protein-associated DNA-strand breaks in mammalian cells treated with m-AMSA might be indicative of a rapid DNA-repair process. The present experiments suggest that such a repair process is unlikely to occur as, even in cells treated with high concentrations of m-AMSA (50 microM) for 20 h, DNA repair replication could not be detected down to the limits of sensitivity (1 million nucleotides replaced per cell).