Antitumor Imidazotetrazines. 41. Conjugation of the Antitumor Agents Mitozolomide and Temozolomide to Peptides and Lexitropsins Bearing DNA Major and Minor Groove-Binding Structural Motifs
作者:Jill Arrowsmith、Sharon A. Jennings、Alan S. Clark、Malcolm F. G. Stevens
DOI:10.1021/jm020936d
日期:2002.12.1
Carboxylic acids derived from the amido groups of the antitumor agents mitozolomide and temozolomide have been conjugated to simple amino acids and peptides by carbodiimide coupling. Solid-state peptide synthesis has been applied to link the acids to DNA major groove-binding peptidic motifs known to adopt alpha-helical conformations. Attachment of the acids to pyrrole and imidazole polyamidic lexitropsins gave a series of potential DNA minor groove- binding ligands. In vitro biological evaluation of a limited number of these novel conjugates failed to demonstrate any enhanced growth-inhibitory activity compared to the unconjugated drugs; sites of alkylation at tracts of multiple guanines were also unaffected. Attachment of additional residues at C-8 of the imidazotetrazines did not perturb the chemistry of activation of the bicyclic nucleus, and biological sequelae can be rationalized by invoking the liberation of a common, diffusible, reactive chemical intermediate, the methanediazonium ion.