NIR-II Responsive Molybdenum Dioxide Nanosystem Manipulating Cellular Immunogenicity for Enhanced Tumor Photoimmunotherapy

Photothermal therapy (PTT) in the second near-infrared (NIR-II) window has emerged as a better candidate for deep-tissue tumor elimination. More interestingly, the photothermal ablated tumor cells also manifest somewhat immunostimulation potency to elicit antitumor immunity, although most dying cells are undergoing apoptosis that is commonly considered as immunologically silent. Here, a NIR-II responsive nanosystem is established for tumor photoimmunotherapy using molybdenum dioxide (MoO2) nanodumbbells as the nanoconverter. Meanwhile, an apoptosis-blocking strategy is proposed to regulate the cell death pattern under NIR-II laser irradiation in order to improve the immunogenic cell death. The nanoformulation can efficiently block caspase 8-dependent apoptotic pathway in photothermal ablated tumor cells and transform into more immunogenic death patterns, thereby activating systemic immunity to inhibit tumor growth and metastasis. In addition, this strategy also helps enhance the body's responses to alpha-PD-1 immune checkpoint inhibitor, which implies a potential optimal combination for cancer immunotherapy.

Automated summary

A new nanosystem for tumor photoimmunotherapy in the second near-infrared window has been developed. This system uses molybdenum dioxide nanodumbbells as nanoconverters and incorporates an apoptosis-blocking strategy to improve immunogenic cell death. The system effectively activates systemic immunity to inhibit tumor growth and metastasis and enhances responses to immune checkpoint inhibitors.