Structural studies on metallobleomycins: The interaction of Pt(II) and Pd(II) with bleomycin

Two of the most successful chemotherapeutic agents used in the treatment of sev- eral neoplasias are bleomycin and cisplatin. Both drugs attack the DNAleading to the cancer cells deathvia different mechanisms. In view of the fact that the combination with each other leads to enhanced activity with less sever side effects, we have undertaken NMR studies on the complexes formed between bleomycin and Pt II ,P d II , cisplatin and transplatin. Herein we present a brief review of the studies on metallobleomycins which were carried out by our lab and others, as an outline of the results obtained using NMR in combination to circular dichroism spectroscopy. Our data indicate that in most cases and under several conditions studied, both metal ions form similar complexes with BLM, while more than one species are present in the solution. Structural implications and comparisons with other metallobleo- mycins are being discussed.