RESUMO
Different antiangiogenic and antimetastatic recombinant adenoviruses were tested in a transgenic mouse model of metastatic ocular cancer (TRP1/SV40 Tag transgenic mice), which is a highly aggressive tumor, developed from the pigmented epithelium of the retina. These vectors, encoding amino-terminal fragments of urokinase plasminogen activator (ATF), angiostatin Kringles (K1-3), endostatin (ES) and canstatin (Can) coupled to human serum albumin (HSA) were injected to assess their metastatic and antiangiogenic activities in our model. Compared to AdCO1 control group, AdATF-HSA did not significantly reduce metastatic growth. In contrast, mice treated with AdK1-3-HSA, AdES-HSA and AdCan-HSA displayed significantly smaller metastases (1.19+/-1.19, 0.87+/-1.5, 0.43+/-0.56 vs controls 4.04+/-5.12 mm3). Moreover, a stronger inhibition of metastatic growth was obtained with AdCan-HSA than with AdK1-3-HSA (P=0.04). Median survival was improved by 4 weeks. A close correlation was observed between the effects of these viruses on metastatic growth and their capacity to inhibit tumor angiogenesis. Our study indicates that systemic antiangiogenic factors production by recombinant adenoviruses, particularly Can, might represent an effective way of delaying metastatic growth via inhibition of angiogenesis.
Assuntos
Inibidores da Angiogênese/genética , Neoplasias Encefálicas/terapia , Neoplasias Oculares/terapia , Técnicas de Transferência de Genes , Terapia Genética , Vetores Genéticos/genética , Albumina Sérica/genética , Fatores Ativadores da Transcrição/genética , Adenoviridae/genética , Inibidores da Angiogênese/uso terapêutico , Angiostatinas/genética , Animais , Proteínas Sanguíneas/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/secundário , Colágeno Tipo IV/genética , Endostatinas/genética , Neoplasias Oculares/genética , Neoplasias Oculares/patologia , Humanos , Camundongos , Camundongos Nus , Camundongos Transgênicos , Neovascularização Patológica , Fragmentos de Peptídeos/genética , Taxa de Sobrevida , Células Tumorais Cultivadas , Ativador de Plasminogênio Tipo Uroquinase/genéticaRESUMO
Since kringle (K)5, not present in the angiostatin molecule, was shown to be a key functional domain possessing potent antiangiogenic activity, we have evaluated a new plasminogen-derived fragment, consisting of the N-terminal part of human plasminogen, that included the complete secondary structure of K1-5 (aa 1-566). In contrast to other fragments described to date, K1-5 includes cysteine residues at positions 543, 555 and 560 allowing the formation of the three disulfide bonds lying within K5. Vascular endothelial cell proliferation and migration assays revealed that a replication-defective adenovirus (AdK1-5(1-566)), expressing K1-5 (aa 1-566), was dose dependently more potent that AdK1-3(1-354), an adenovirus that expresses only the first three kringles. In contrast to AdK1-3(1-354), a single intratumoral injection of AdK1-5(1-566) into MDA-MB-231 breast human carcinoma tumors was followed by a total regression of 40% of the tumor and by significant arrest of tumor growth (90%), which was correlated with a drastic decrease of functional neovascularization into the tumors. Furthermore, systemic delivery of AdK1-5(1-566) in mice inhibited the lung invasion of melanoma B16-F10 cells by 87%. Our findings provide evidence that the full kringles of plasminogen (aa 1-566) may be much more potent than K1-3 (aa 1-354), for the suppression of angiogenesis, tumor growth and metastatic dissemination.
