The cytotoxicity of copper(II) complexes of 2-acetyl-pyridyl-4N-substituted thiosemicarbazones.

A series of 2-acetyl-pyridyl-4N-substituted thiosemicarbazones copper(II) complexes was evaluated for their cytotoxic mode of action in a variety of human and rodent tumor cell cultures. It was determined that these compounds may induce cytotoxicity by affecting several metabolic pathways including a reduction in de novo purine synthesis, and inhibition of IMP dehydrogenase, and DNA polymerase alpha activities. Selected compounds also demonstrated the ability to inhibit L1210 DNA topoisomerase II activity at micromolar concentrations. These agents were able to antagonize etoposide-induced formation of cleavable complexes as measured by K+/SDS precipitation and in vitro cleavage reactions.