RESUMO
The NADPH oxidase 2 (NOX2) complex is a professional producer of reactive oxygen species (ROS) and is mainly expressed in phagocytes. While the activity of the NOX2 complex is essential for immunity against pathogens and protection against autoimmunity, its role in the development of malignant tumors remains unclear. We compared wild type and Ncf1 (m1J) mutated mice, which lack functional NOX2 complex, in four different tumor models. Ncf1 (m1J) mutated mice developed significantly smaller tumors in two melanoma models in which B16 melanoma cells expressing a hematopoietic growth factor FLT3L or luciferase reporter were used. Ncf1 (m1J) mutated mice developed significantly fewer Lewis Lung Carcinoma (LLC) tumors, but the tumors that did develop, grew at a pace that was similar to the wild type mice. In the spontaneously arising prostate carcinoma model (TRAMP), tumor growth was not affected. The lack of ROS-mediated protection against tumor growth was associated with increased production of immunity-associated cytokines. A significant increase in Th2 associated cytokines was observed in the LLC model. Our present data show that ROS regulate rejection of the antigenic B16-luc and LLC tumors, whereas the data do not support a role for ROS in growth of intrinsically generated tumors.
Assuntos
Carcinoma/genética , Carcinoma/patologia , Melanoma/genética , Melanoma/patologia , NADPH Oxidases/genética , Neoplasias/genética , Neoplasias/patologia , Animais , Carcinoma/metabolismo , Carcinoma/mortalidade , Carcinoma Pulmonar de Lewis , Modelos Animais de Doenças , Inflamação/genética , Inflamação/metabolismo , Melanoma/metabolismo , Melanoma/mortalidade , Melanoma Experimental , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Mutação , NADPH Oxidases/deficiência , NADPH Oxidases/metabolismo , Neoplasias/metabolismo , Neoplasias/mortalidade , Espécies Reativas de Oxigênio/imunologia , Carga Tumoral/genéticaRESUMO
Extracellular superoxide dismutase (SOD3), an enzyme mediating dismutation of superoxide into hydrogen peroxide, has been shown to reduce inflammation by inhibiting macrophage migration into injured tissues. In inflamed tissues, superoxide is produced by the phagocytic NOX2 complex, which consists of the catalytic subunit NOX2 and several regulatory subunits (e.g., NCF1). To analyze whether SOD3 can regulate inflammation in the absence of functional NOX2 complex, we injected an adenoviral vector overexpressing SOD3 directly into the arthritic paws of Ncf1(∗/∗) mice with collagen-induced arthritis. SOD3 reduced arthritis severity in both oxidative burst-deficient Ncf1(∗/∗) mice and also in wild-type mice. The NOX2 complex independent anti-inflammatory effect of SOD3 was further characterized in peritonitis, and SOD3 was found to reduce macrophage infiltration independently of NOX2 complex functionality. We conclude that the SOD3-mediated anti-inflammatory effect on arthritis and peritonitis operates independently of NOX2 complex derived oxidative burst.
