RESUMEN
Slit is a secreted protein known to function through the Roundabout (Robo) receptor as a repellent for axon guidance and neuronal migration, and as an inhibitor in leukocyte chemotaxis. We have previously shown that Slit2 is also secreted by a variety of human cancer cells whereby it acts as a chemoattractant to vascular endothelial cells for tumor angiogenesis. We used a blocking antibody to investigate the role of Slit-Robo signaling in tumor angiogenesis during oral carcinogenesis. In this report we undertook a multistage model of 7,12-dimethyl-1,2-benzanthracene-induced squamous cell carcinoma in the hamster buccal pouch. R5, a monoclonal antibody against the first immunoglobulin domain of Robo1, was used to study whether R5 blocks the Slit-Robo interaction and furthermore inhibits tumor angiogenesis and growth in our model. In addition, the expression of Slit2, von Willebrand factor, and vascular endothelial growth factor were examined using human tissue of oral cheek mucosa with oral squamous cell carcinoma. Our data showed that Slit2 was expressed minimally in normal and hyperplastic mucosa, moderately in dysplastic mucosa, and highly in neoplastic mucosa obtained from hamster buccal pouch. We also found that increased Slit2 expression was associated with higher tumor angiogenesis, as reflected by increased vascular endothelial growth factor expression and microvessel density. A similar Slit2 expression profile was found in human tissue. Importantly, interruption of the Slit2-Robo interaction using R5 inhibited tumor angiogenesis and growth in our in vivo model, which indicates that Slit2-mediated tumor angiogenesis is a critical process underlying the carcinogenesis of chemical-induced squamous cell carcinoma. Therefore, targeting Slit-Robo signaling may offer a novel antiangiogenesis approach for oral cancer therapy.
Asunto(s)
Carcinoma de Células Escamosas/irrigación sanguínea , Neovascularización Patológica/metabolismo , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Receptores Inmunológicos/antagonistas & inhibidores , Transducción de Señal , 9,10-Dimetil-1,2-benzantraceno , Alantoides/metabolismo , Animales , Carcinógenos , Carcinoma de Células Escamosas/inducido químicamente , Carcinoma de Células Escamosas/metabolismo , Embrión de Pollo/metabolismo , Cricetinae , Humanos , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Masculino , Proteínas del Tejido Nervioso/metabolismo , Receptores Inmunológicos/metabolismo , Células Tumorales Cultivadas , Factor A de Crecimiento Endotelial Vascular/metabolismo , Factor de von Willebrand/metabolismo , Proteínas RoundaboutRESUMEN
The interaction of bacillus subtilis proteinase(BSP) and Alizarin Complex (ALC) was investigated by spectrophotometric method in acidic solution(pH 4.20). When BSP was added into ALC, a red color was observed, which indicated the formation of BSP-ALC associated compound. The maximum absorption of the red color coordination compound was obtained at 510 nm. It was found that the red shift of maximum absorption of the complex was 85 nm. According to balance percolation method, molar ratio method and double wavelengh method, the apparent molar absorptivity epsilonB = 6.68 x 10(3) L x mol(-1) x cm(-1). Conditional constants were defined, the maximum binding number n = 10, and the apparent binding constant K = 7. 25 x 10(6) L x mol(-1). It was found that Scatchard model is appropriate in the treatment of data obtained here.