RESUMEN

Hypoxia has been shown to promote metastasis of cancer cells through induction of epithelial-mesenchymal transition (EMT). It is also known to cause generation of reactive oxygen species (ROS). We investigated here the role of ROS in hypoxia-induced EMT and whether attenuation of ROS by antioxidants suppresses hypoxia-induced EMT and metastasis of human pancreatic cancer cells in a xenograft nude mouse model. PANC-1 and MiaPaCa-2 cells exposed to hypoxia (1 % O(2)) showed increased ROS generation and characteristic changes of EMT such as morphological changes, enhanced invasiveness, and upregulation of EMT regulators, SLUG, SNAI1 and TWIST. The antioxidants N-acetylcysteine (NAC) and ebselen significantly suppressed EMT and the expression of EMT regulators during hypoxia. NAC abrogated activation of HIF-1α and NF-κB, both of which were found to play an active role in hypoxia-induced EMT. Administration of NAC to nude mice with orthotopic tumors suppressed the expression of EMT regulators in hypoxic areas and significantly inhibited hepatic metastasis. Together, the present findings demonstrate that attenuation of ROS by antioxidants suppresses hypoxia-induced EMT and metastatic phenotype, suggesting that antioxidants may be of therapeutic value in treating pancreatic cancers.

Asunto(s)

Acetilcisteína/uso terapéutico , Antioxidantes/uso terapéutico , Transición Epitelial-Mesenquimal/efectos de los fármacos , Hipoxia/patología , Neoplasias Hepáticas/prevención & control , Neoplasias Pancreáticas/prevención & control , Especies Reactivas de Oxígeno/metabolismo , Animales , Apoptosis/efectos de los fármacos , Western Blotting , Adhesión Celular , Movimiento Celular , Proliferación Celular , Femenino , Técnica del Anticuerpo Fluorescente , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/antagonistas & inhibidores , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/secundario , Ratones , Ratones Desnudos , FN-kappa B/antagonistas & inhibidores , FN-kappa B/genética , FN-kappa B/metabolismo , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patología , ARN Mensajero/genética , ARN Interferente Pequeño/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Transcripción de la Familia Snail , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Células Tumorales Cultivadas , Proteína 1 Relacionada con Twist/genética , Proteína 1 Relacionada con Twist/metabolismo