Metal complexes as photochemical nitric oxide precursors: Potential applications in the treatment of tumors

The bioregulatory molecule NO plays key roles in cancer biology and has been implicated in both tumor growth and suppression. Furthermore, it is a gamma-radiation sensitizer that may enhance selective killing of neoplastic tissues. For these reasons, there is considerable interest in developing methods for NO delivery to specific physiological targets. In this Perspective, we describe ongoing investigations focused on photochemical methodologies to deliver therapeutic doses of NO to such targets utilizing transition metal complexes that are nitric oxide precursors. The photochemical strategy has the advantages that it allows for precise control of the timing, location, and dosage for the targeted delivery of a bioactive agent.