Oxidative activation of leinamycin E1 triggers alkylation of guanine residues in double-stranded DNA.

It may be useful to develop prodrugs that are selectively activated by oxidative stress in cancer cells to release cell-killing reactive intermediates. However, relatively few chemical strategies exist for the activation of prodrugs under conditions of oxidative stress. Here we provide evidence for a novel process in which oxidation of a thiol residue in the natural product leinamycin E1 by H ₂ O ₂ and other byproducts of cellular oxidative stress initiates generation of an episulfonium ion that selectively alkylates guanine residues in duplex DNA.