RESUMO
There is growing evidence that necrosis, instead of apoptosis, could act as a natural adjuvant, which could activate an immune response. In this work we have investigated if induction of tumor necrosis could trigger the affluence of inflammatory cells at the tumor site, and thus induce an immune response. For this purpose, a liquid N2 spray was applied on human melanoma (IIB-MEL-J cell line) xenografted in nude mice and 24 h later some mice received intratumorally a single 500 U dose of recombinant murine granulocyte macrophage-colony-stimulating factor. 77-100% of the tumor mass underwent necrosis. Congestion, edema, and endothelial cell activation were the first noticeable events. A quick infiltrative response of polymorphonuclear leukocytes around the tumor was detected 24 h after liquid N2 application, peaking at day 3. Massive macrophage recruitment was observed since day 3. An early intratumoral infiltration with inflammatory cells was only detected in the group that received recombinant murine granulocyte macrophage- colony-stimulating factor after necrosis induction by liquid N2. Coexisting DEC 205- and F4/80-positive cells increased in number, and their localization was predominantly peritumoral after necrosis. Antibody response was only detected in the groups with tumor-induced necrosis. Our results suggest that cryosurgery-induced necrosis could be a useful model to analyze the interaction among necrosis, inflammation, and the generation of an immune response.
Assuntos
Criocirurgia/efeitos adversos , Inflamação/patologia , Melanoma/patologia , Neoplasias Cutâneas/patologia , Animais , Formação de Anticorpos , Edema/patologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/uso terapêutico , Humanos , Macrófagos/patologia , Melanoma/imunologia , Melanoma/terapia , Camundongos , Camundongos Nus , Necrose , Transplante de Neoplasias , Neutrófilos/patologia , Período Pós-Operatório , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/terapia , Transplante Heterólogo , Células Tumorais CultivadasRESUMO
Rhodanese (thiosulphate:cyanide sulphurtransferase) shows distinctive mitochondrial and cytoplasmic activities in several models of tumorigenesis. To investigate the basis for these differences, the enzyme was purified from mitochondrial and cytosolic liver fractions of mice treated with the carcinogen p-dimethyl-aminoazobenzene (DAB) and some inhibition kinetic studies were carried out. When both substrates were assayed at inhibitory levels, non-competitive inhibition was observed for the second substrate at variable concentrations, the reversible connection between both substrates was attained by the instability of the second enzyme form. It is suggested that the enzyme might be changing from an unstable ES form to a more stable sulphur substituted intermediate as a consequence of DAB treatment. Sulphite was a competitive inhibitor vs thiosulphate for rhodanese isolated from normal liver and a hyperbolic activator for the enzyme isolated from liver of DAB-treated animals.
Assuntos
Carcinógenos/farmacologia , Inibidores Enzimáticos/farmacocinética , Fígado/efeitos dos fármacos , Fígado/enzimologia , Mitocôndrias Hepáticas/efeitos dos fármacos , Mitocôndrias Hepáticas/enzimologia , Tiossulfato Sulfurtransferase/antagonistas & inibidores , Tiossulfato Sulfurtransferase/metabolismo , p-Dimetilaminoazobenzeno/farmacologia , Animais , Cianetos/farmacologia , Citosol/efeitos dos fármacos , Citosol/enzimologia , Inibidores Enzimáticos/farmacologia , Cinética , Masculino , Camundongos , Camundongos Endogâmicos , Tiossulfatos/farmacologiaRESUMO
In order to clearly visualize blood vessels, the monoclonal antibody (mAb) MEC 13.3 was used for an immunohistochemical staining on frozen sections of different mice mammary tumors. MEC 13.3 mAb is specific for endothelial cells (ECs) of mouse blood vessels and recognizes a molecule related to the murine form of CD31/PECAM. This mAb with immunoenzymatic technique or immunofluorescent labelling, was found to be a useful tool to quantify tumor neovascularization. Specifically, membrane reinforcement could be observed in vessel ECs, indicating the expression of CD31/ PECAM in their surface. The staining of ECs from tumors and from normal tissues was also compared. In this work, the use of MEC13.3 mAb is reported to recognize mice mammary tumor ECs as a useful tool to identify neovascularization. It would also be helpful for research on the origin and function of vascular endothelium in murine tumor experimental models.