Project 4 will address fundamental questions related to the structure and function of iron bleomycins and will design and synthesize novel bleomycin-based compounds with increased sequence specificity.  The overall objective of this proposal is to understand the structure and reactivity of bleomycins and to develop structurally modified bleomycins that can be used to obtain better and more efficient cancer treatments.  The bleomycins are a group of glycopeptide antibiotics synthesized by Streptomyces verticilus that have been used for the treatment of head and neck cancer, certain lymphomas, and testicular cancer.  The mechanism of cytoxicity appears to be related to the ability of bleomycins to specifically bind and cleave duplex DNA.  An NMR-determined structure of Co(III)-Bleomycin bound to an oligonucleotide duplex has led to a model of the mechanism by which both strands are cleaved as the result of a single binding event (Hoehn et al, 2001).  Using approaches that include high-level quantum chemistry, molecular modelling, NMR analysis, molecular specificity analysis, and in vitro and in vivo testing, we will characterize the efficacy of the new agents.

Specific aims of this Project are to:

1. calculate the structure of derivatives of iron-bleomycin prior to DNA binding, as well as to calculate the structure and dynamics of Fe(II)-BLM bound to DNA;
2. synthesize and test the Bleomycin derivatives;
3. design and synthesis Bleomycin-TFO conjugates; and
4. characterize the molecular specificity and growth inhibitory activity of Bleomycin derivatives.

The accomplishment of these aims is likely to result in a new class of agents that may be targeted to specific gene sequences.