Modulation of mutagenic properties in a series of DNA-directed alkylating agents by variation of chain length and alkylator reactivity

Abstract

Four series of aniline mustards linked to a DNA-affinic acridine chromophore by alkyl chains of varying length (2–5 carbon atoms) have been studied for their mutagenic properties, as estimated in four strains of Salmonella typhimurium and in Saccharomyces cerevisiae strain D5. The four series have very different mustard reactivities, as determined by the aniline link group (-O-, -CH 2-, -S- or -SO 2-). Some of the derived compounds cause frameshift mutagenesis which can be detected in TA98 and also “petite” mutagenesis activity, neither of which occur to significant extents with the parent mustards of with 9-aminoacridine. None of the derived compounds are as effective as the parent mustards in mitotic crossing-over, nor do they show ability for frameshift mutagenesis in S. typhimurium TA1977 which is typical of acridines. Some of the compounds have comparable frameshift activity to compounds such as ICR-191, but appear to have a different base-pair preference. The results indicate clear structure-activity relationships for the spectrum of mutagenic activity, which relate to both chain length and alkylator reactivity, for these compounds.