Nitroreductase-activated nitric oxide (NO) prodrugs.

Due to the involvement of nitric oxide (NO) in numerous and diverse physiological processes, site-directed delivery of therapeutic NO in order to minimize unwanted side-effects is necessary. O(2)-(4-Nitrobenzyl) diazeniumdiolates are designed as substrates for Escherichia coli nitroreductase (NTR), an enzyme that is frequently used to facilitate directed delivery of cytotoxic species to cancers. O(2)-(4-Nitrobenzyl) diazeniumdiolates are found to be stable in aqueous buffer but are metabolized by NTR to produce NO. A cell viability assay revealed that cytotoxic effects of O(2)-(4-nitrobenzyl)1-(2-methylpiperidin-1-yl)diazen-1-ium-1,2-diolate (4b) towards two cancer cell lines is significantly enhanced in the presence of NTR suggesting the potential for use of this compound in nitric oxide-based directed prodrug therapy.