Potential antitumor agents. 31. Quantitative structure-activity relationships for the antileukemic bis(guanylhydrazones)

Abstract

Certain L-1210[mouse leukemia cells]-active bis(guanylhydrazones) have structural and biological properties in common with the DNA minor groove binding, antileukemic, bisquaternary ammonium heterocycles. Monitoring of the DNA binding of the bis(guanylhydrazones), by fluorimetric quantitation of drug displacement of DNA-bound ethidium, shows that, like the bisquaternary salts, these agents bind more strongly to poly[d(A-T)] [adenine-thymine] than poly[d(G-C)] [guanine-cytosine]. The drug concentrations necessary to inhibit L-1210 DNA-dependent DNA polymerase in vitro by 50% (IC50) are linearly related to measures of drug-DNA binding with no preference for a particular primary sequence of DNA being evident. Mammalian toxicity of the bis(guanylhydrazones) is effectively modeled by a regression equation containing binomial terms in Rm values, used as a measure of agent lipophilic-hydrophilic balance, and the logarithms of the IC50 values.