重粒子線癌治療におけるNO ラジカルの役割

To investigate whether the bystander effect mediated nitric oxide (NO) radicals excreted from the tumor irradiated with accelerated carbon ion beams modulates growth of the unirradiated tumor at an opposite side in the same mouse. Also, to investigate whether NO generating agents can sensitize the tumoricidal effect by accelerated carbon ion beams. NO at the relatively low concentrations, which excreted from the irradiated donor tumors with accelerated carbon ion beams induced both inhibition and stimulation of tumor regrowth. These findings indicate the importance of an intercellular signal transduction pathway initiated by NO in cellular response to radiation. On the other hand, NO at the relatively high concentrations (0.3 mM) sensitized the tumoricidal effect of X-rays in the p53-independent manner