RESUMO
BACKGROUND: IL-12 has been successfully used in experimental tumor therapy. However, administration of this cytokine induces dose-dependent suppression of hematopoiesis that could potentially limit its use in clinical trials. We decided to examine whether the myelosuppressive activity of IL-12 could be corrected by the administration of G-CSF. MATERIALS AND METHODS: In the initial experiments the influence of IL-12 and/or G-CSF on bone marrow and spleen GM-CFC was evaluated. To examine whether C-CSF could influence the antitumor activity of IL-12 the combination therapy with these agents was carried out starting on day seven following inoculation of melanoma MmB16 cells into the footpads of B6D2F1 mice. To obtain insight into the mechanism of the observed augmented antitumor activity of the combination therapy with IL-12 and G-CSF, the influence of these cytokines on macrophage activity (cytotoxicity and nitric oxide release) was analyzed. RESULTS: In accord with our expectations, the application of G-CSF partially prevented the suppression of bone marrow myelopoiesis in IL-12 treated mice. Unexpectedly, G-CSF also showed potentiation of antitumor effects of IL-12 in this melanoma model. The augmented antitumor activity of combined IL-12/G-CSF immunotherapy could result from the enhanced stimulation of macrophage NO production and cytotoxicity. CONCLUSION: The simultaneous administration of IL-12 and G-CSF partially prevented suppression of bone marrow myelopoiesis in IL-12-treated mice. Moreover, treatment with these cytokines also results in potentiated antitumor effects in a murine melanoma model.
Assuntos
Antineoplásicos/uso terapêutico , Medula Óssea/efeitos dos fármacos , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Hematopoese/efeitos dos fármacos , Interleucina-12/uso terapêutico , Melanoma Experimental/tratamento farmacológico , Animais , Modelos Animais de Doenças , Interações Medicamentosas , Interleucina-12/antagonistas & inibidores , Contagem de Leucócitos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Óxido Nítrico/biossíntese , Proteínas Recombinantes/uso terapêutico , Baço/efeitos dos fármacosRESUMO
Granulocyte colony-stimulating factor (G-CSF) was found to exert antitumor activity against murine MmB16 melanoma when administered intratumorally. However, subcutaneous administration of this cytokine at a site distant from the growing tumor did not show any antitumor effects. G-CSF did not influence the proliferative activity of MmB16 in vitro. Intraperitoneal administration of G-CSF resulted in decreased secretion of nitric oxide (NO) by peritoneal macrophages and their decreased tumoricidal activity against MmB16.
Assuntos
Antineoplásicos/uso terapêutico , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Melanoma Experimental/tratamento farmacológico , Animais , Divisão Celular/efeitos dos fármacos , Modelos Animais de Doenças , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Óxido Nítrico/biossíntese , Proteínas RecombinantesRESUMO
To study the antitumor activity of the combination immunotherapy with interleukin-12 (IL-12) and granulocyte-macrophage colony-stimulating factor (GM-CSF), a murine MmB 16 melanoma tumor model was used. Seven days after inoculation of MmB 16 melanoma cells into the footpad of the right hind limb, mice were treated with IL-12 and/or GM-CSF administered intratumorally for 7 consecutive days. IL-12 used both at a high (1 microg) and at a low (0.01 microg) dose per day produced retardation of tumor growth, although neither treatment resulted in any significant prolongation of the survival of tumor-bearing mice. GM-CSF did not by itself exert antitumor activity in this model; however, it potentiated antitumor effects of IL-12. In particular, survival of tumor-bearing mice treated with IL-12 (0.01 microg per day) and GM-CSF was significantly prolonged compared with that in mice treated with either IL-12 or GM-CSF alone.
Assuntos
Fator Estimulador de Colônias de Granulócitos e Macrófagos/uso terapêutico , Interleucina-12/uso terapêutico , Melanoma Experimental/terapia , Animais , Divisão Celular , Sobrevivência Celular , Sinergismo Farmacológico , Contagem de Eritrócitos/efeitos dos fármacos , Membro Posterior , Contagem de Leucócitos/efeitos dos fármacos , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/fisiologia , Melanoma Experimental/sangue , Melanoma Experimental/patologia , Camundongos , Óxido Nítrico/biossíntese , Tamanho do Órgão/efeitos dos fármacos , Contagem de Plaquetas/efeitos dos fármacos , Proteínas Recombinantes/uso terapêutico , Baço/efeitos dos fármacos , Fatores de TempoRESUMO
Of a number of factors involved in apoptosis, protease activity may play a crucial role. We show that N-benzyloxycarbonyl-Ile-Glu( O-t-butyl)-Ala-leucinal (PSI), a selective inhibitor of the chymotrypsin-like activity of the proteasome, induces massive apoptosis in murine leukaemia L1210 cells. At 50 nM concentration, PSI induces a block of cytokinesis, while higher concentrations (500 nM) cause S phase block and massive apoptosis. Z-Leu-leucinal, a specific calpain inhibitor, did not induce apoptosis. In contrast to previous reports, TNF-alpha did not enhance apoptosis when combined with PSI. Our results suggest that proteasome inhibitors may be considered as potential anti-neoplastic agents.