Boosting immunogenic cell death via hollow MnO2-based multiple stimuli-responsive drug delivery systems for improved cancer immunotherapy

Cancer treatment by inducing tumor cell immunogenic cell death (ICD) is critical for tumor therapy. However, ICD activation by single pathway is often limited in practical application due to its low efficiency. In addition, the low pH and anoxic microenvironments in solid tumors greatly limit the effective activation of ICD. Herein, hollow manganese dioxide (H-MnO2) nanomaterials were selected to load both Mitoxantrone (MTZ) and Chlorin e6 (Ce6) due to its hollow structure and ability to release drugs in the acidic environments. Thus, the synergy of photodynamic therapy (PDT), photothermal therapy (PTT) and chemotherapy can induce the process of immunogenic cell death, stimulate the maturation of dendritic cells (DCs), and activate the immune response to kill tumor cells dramatically. Efficient immunotherapeutic effects were obtained when MnO2-C/M-HA was given intravenously to 4T1 tumor-bearing BALB/c mice with 660 nm near-infrared laser irradiation. This study overcame the limitations of monotherapy and provided a multifunctional platform for tumor immunotherapy.