RESUMEN
We have previously reported that superoxide stimulates the motility of tumor cells and the administration of Cu-Zn superoxide dismutase (SOD) significantly suppresses metastasis. However, ideally, anti-metastatic therapy should be long-lasting, systemically effective and have low toxicity. The half-life of Cu-Zn SOD in plasma is so short that it cannot provide long-lasting effects. Therefore, in this study we have developed a gene therapy in a mouse model utilizing extracellular SOD (EC-SOD), which is the most prevalent SOD isoenzyme in extracellular fluids. We retrovirally transfected fibroblasts (syngeneic) with the EC-SOD gene and established EC-SOD-secreting fibroblasts. Inoculation of EC-SOD-secreting fibroblasts suppressed both artificial and spontaneous metastatic lung nodules in mouse metastasis models. These data indicate the feasibility of anti-metastatic gene therapy utilizing the EC-SOD gene.
Asunto(s)
Terapia Genética/métodos , Neoplasias Pulmonares/secundario , Neoplasias Pulmonares/terapia , Superóxido Dismutasa/genética , Transducción Genética , Animales , Carcinoma Pulmonar de Lewis/patología , Carcinoma Pulmonar de Lewis/secundario , Carcinoma Pulmonar de Lewis/terapia , Técnicas de Cultivo de Célula , División Celular , Medios de Cultivo , ADN Complementario/genética , Estudios de Factibilidad , Fibroblastos/trasplante , Expresión Génica , Isoenzimas/genética , Isoenzimas/metabolismo , Neoplasias Pulmonares/patología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos , Trasplante de Neoplasias , ARN Mensajero/genética , Sarcoma Experimental/patología , Sarcoma Experimental/secundario , Sarcoma Experimental/terapia , Superóxido Dismutasa/metabolismoRESUMEN
The molecular basis of the polymorphic tumor rejection antigens of chemically induced sarcomas of inbred mice remains a mystery, despite the discovery of these antigens over 40 years ago and their critical importance to the foundation of tumor immunology. In an analysis of a panel of BALB/c 3-methylcholanthrene-induced tumors, we identified one tumor, CMS5, that elicited a strong cytotoxic T cell response with exquisite specificity for CMS5. A stable cloned line of T cells with this specificity (C18) was used to screen a CMS5 cDNA expression library. The gene encoding the C18-defined antigen was identified as a mutated form of a mouse mitogen-activated protein kinase, ERK2, and a peptide incorporating the resulting amino acid substitution (lysine to glutamine) was efficiently recognized by C18. Vaccination with this peptide elicited specific resistance to CMS5 challenge. Extensive efforts to isolate antigen-loss variants of CMS5 were unsuccessful, suggesting that the mutated mitogen-activated protein kinase is essential for maintenance of the malignant phenotype.