Captopril and S-nitrosocaptopril as potent radiosensitizers: Comparative study and underlying mechanisms.

In an effort to improve the issue of radiotherapy treatments, we tested whether S-nitrosocaptopril, a molecule combining a NO donor and an angiotensin converting enzyme inhibitor (ACE inhibitor), could temporarily improve the hemodynamic status of experimental tumors. We monitored the effect of S-nitrosocaptopril in TLT tumors using non rinvasive magnetic resonance techniques. We identified a time window during which tumor oxygenation was improved, as a result of a combined effect on tumor blood flow and oxygen consumption. Consequently, the administration of S-nitrosocaptopril contributed to the increase in efficacy of radiation therapy, an effect that was not observed with captopril alone.