RESUMEN
Metastasis accounts for 90% of cancer-related deaths and, currently, there are no effective clinical therapies to block the metastatic cascade. A need to develop novel therapies specifically targeting fundamental metastasis processes remains urgent. Here, we demonstrate that Salmonella YB1, an engineered oxygen-sensitive strain, potently inhibits metastasis of a broad range of cancers. This process requires both IFN-γ and NK cells, as the absence of IFN-γ greatly reduces, whilst depletion of NK cells in vivo completely abolishes, the anti-metastatic ability of Salmonella. Mechanistically, we find that IFN-γ is mainly produced by NK cells during early Salmonella infection, and in turn, IFN-γ promotes the accumulation, activation, and cytotoxicity of NK cells, which kill the metastatic cancer cells thus achieving an anti-metastatic effect. Our findings highlight the significance of a self-regulatory feedback loop of NK cells in inhibiting metastasis, pointing a possible approach to develop anti-metastatic therapies by harnessing the power of NK cells.
Asunto(s)
Interferón gamma/metabolismo , Interferón gamma/farmacología , Células Asesinas Naturales/inmunología , Activación de Linfocitos/efectos de los fármacos , Metástasis de la Neoplasia/inmunología , Infecciones por Salmonella/metabolismo , Salmonella/genética , Animales , Citocinas/metabolismo , Femenino , Inmunidad Innata , Inmunoterapia/métodos , Interferón gamma/genética , Neoplasias Pulmonares/inmunología , Neoplasias Pulmonares/patología , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Infecciones por Salmonella/tratamiento farmacológicoRESUMEN
The migration of immune cells is crucial to the immune response. Visualization of these processes has previously been limited because of the imaging depth. We developed a deep-penetrating, sensitive and high-resolution method to use fast photoacoustic tomography (PAT) to image the dynamic changes of T cells in lymph node and diseases at new depth (up to 9.5 mm). T cells labeled with NIR-797-isothiocyanate, an excellent near-infrared photoacoustic and fluorescent agent, were intravenously injected to the mice. We used fluorescence imaging to determine the location of T cells roughly and photoacoustic imaging is used to observe T-cell responses in diseased sites deeply and carefully. The dynamic changes of T cells in lymph node, acute disease (bacterial infection) and chronic disease (tumor) were observed noninvasively by photoacoustic and fluorescence imaging at different time points. T cells accumulated gradually and reached a maximum at 4 hours and declined afterwards in lymph node and bacterial infection site. At tumor model, T cells immigrated to the tumor with a maximum at 12 hours. Our study can not only provide a new observing method for immune activities tracking, but also enable continuous monitoring for therapeutic interventions.