Therapeutics: Nitric oxide (NO) synthase; interleukin-10 (IL-10)

Mouse studies suggest inhibiting NO synthase or IL-10 could increase the anti-tumor effects of radiation. Radiotherapy can induce NO synthase and T helper type 2 (Th2) cell secretion of IL-10, both of which can promote tumor growth. In a syngeneic mouse model of squamous cell carcinoma, radiotherapy and an NO synthase inhibitor decreased tumor growth and levels IL-10 compared with radiation alone. Also in the model, radiotherapy and an anti-IL-10 morpholino decreased tumor growth comparably to radiotherapy and the NO synthase inhibitor. Next steps could include testing the combination of radiation plus inhibition of NO synthase or IL-10 in additional tumor models...