Anti-cancer activity of anthracycline antibiotics and DNA condensation.

Light scattering techniques were used to investigate the ability of a number of anthracyclines to cause compaction in double-stranded DNA and nucleosomes at physiological ionic strength. The structurally organized polynucleotide was efficiently condensed by all of the drugs examined, while no appreciable aggregation of free double-stranded DNA is observed under the same experimental conditions. A model for the process is proposed. Our results suggest the lack of a direct relationship between the critical concentration of free drug at which condensation of DNA occurs and the cytotoxic and anti-cancer properties exhibited by the various anthracycline derivatives.