Coupling nitric oxide photo-uncaging with radiotherapy

Abstract

In this review we discuss some issues and problems with radiotherapy of disease states such as cancer. An important issue is that radiation induced tissue mortality is enhanced by the presence of oxygen, a feature that often leads to normoxic healthy tissues being more sensitive to high energy radiation than tumor tissues, which are often hypoxic. These properties lead to an interest in the delivery of radiation sensitizers to the targeted tissues, and a technique for doing so is photo-uncaging, which allows spatial-temporal control. One such radiation sensitizer is the small molecule bioregulator nitric oxide (NO), for which photo-uncaging has been demonstrated with a number of transition metal nitrosyl complexes. The review will explore potential approaches for photo-uncaging NO in targeted tissues, including the possible utilization of the therapeutic high energy radiation itself (“radio-uncaging”).