ABSTRACT
Cancer vaccines represent a promising immunotherapeutic treatment modality. The promotion of cross-presentation of extracellular tumor-associated antigens on the major histocompatibility complex (MHC) class I molecules and dendritic cell maturation at the appropriate time and place is crucial for cancer vaccines to prime cytolytic T cell response with reduced side effects. Current vaccination strategies, however, are not able to achieve the spatiotemporal control of antigen cross-presentation. Here, we report a liposomal vaccine loading the second near-infrared window (NIR-II, 1000-1700 nm) fluorophore BPBBT with an efficient photothermal conversion effect that offers an NIR-light-triggered endolysosomal escape under the imaging guidance. The NIR-II image-guided vaccination strategy specifically controls the cytosolic delivery of antigens for cross-presentation in the draining lymph nodes (DLNs). Moreover, the photothermally induced endolysosomal rupture initiates autophagy. We also find that the adjuvant simvastatin acts as an autophagy activator through inhibiting the PI3K/AKT/mTOR pathway. The light-induced autophagy in the DLNs together with simvastatin treatment cooperatively increase MHC class II expression by activating autophagy machinery for dendritic cell maturation. This study presents a paradigm of NIR-II image-guided light-triggered vaccination. The approach for remote control of antigen cross-presentation and autophagy represents a new strategy for vaccine development.
ABSTRACT
Compared to conventional cancer treatment, combination therapy based on well-designed nanoscale platforms may offer an opportunity to eliminate tumors and reduce recurrence and metastasis. In this study, we prepared multifunctional microspheres loading I-labeled hollow copper sulfide nanoparticles and paclitaxel (I-HCuSNPs-MS-PTX) for imaging and therapeutics of W256/B breast tumors in rats. F-fluordeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) imaging detected that the expansion of the tumor volume was delayed (<0.05) following intra-tumoral (i.t.) injection with I-HCuSNPs-MS-PTX plus near-infrared (NIR) irradiation. The immunohistochemical analysis further confirmed the anti-tumor effect. The single photon emission computed tomography (SPECT)/photoacoustic imaging mediated by I-HCuSNPs-MS-PTX demonstrated that microspheres were mainly distributed in the tumors with a relatively low distribution in other organs. Our results revealed that I-HCuSNPs-MS-PTX offered combined photothermal, chemo- and radio-therapies, eliminating tumors at a relatively low dose, as well as allowing SPECT/CT and photoacoustic imaging monitoring of distribution of the injected agents non-invasively. The copper sulfide-loaded microspheres, I-HCuSNPs-MS-PTX, can serve as a versatile theranostic agent in an orthotopic breast cancer model.