Reprogramming of tumor associated macrophages (TAMs) from M2 to M1 phenotype is becoming a feasible strategy for tumor immunotherapy, however, its efficacy is potentially constrained by the acellular components of immunosuppressive tumor microenvironment (TME). Herein, hollow MnO 2 (HMnO 2 ) nanoparticles were loaded with autophagy inhibitor chloroquine (CQ), carried both lactate oxidase (LOX) and glucose oxidase (GOX) on their surface, and further were camouflaged with tumor cell membrane, forming the final mCMLG nanoparticles for TME immunostimulation. After intravenous injection, mCMLG nanoparticles effectively accumulated in the tumor area and were taken up by tumor cells. Under the acidic conditions, MnO 2 reacted with endogenous hydrogen peroxide (H 2 O 2 ) to generate O 2 and Mn 2+ , resulting in the exposure of LOX and GOX as well as the release of CQ. The exposed enzymes reduced the level of lactate (a predominant acellular component), alleviating the inhibition on TAM reprogramming; hydroxyl radical (·OH) generated by Fenton-like reaction of Mn 2+ could directly promote this reprogramming, thus effectively facilitating the reprogramming of TME from immunosuppressive to immunostimulatory. Moreover, ·OH also induced chemodynamic therapy (CDT) effect against tumor cells, which was further amplified by CQ. This study corroborates that mCMLG nanoparticles can effectively inhibit tumor growth through the enhanced immunotherapy and CDT.
Low tumor mutational burden and absence of T cells within the tumor sites are typical characteristics of “cold immune tumors” that paralyzes the immune system. The strategy of reversing “cold tumors” to “hot tumors” infiltrated high degree of T cells in order to activate anti-tumor immunity has attracted lots of attentions. Herein, immunogenic core–shell [email protected] NPs is fabricated by gold-selenium coordination bond to realize nanoparticles-mediated local photothermal-triggered immunotherapy. As expected, incorporation of gold nanostars (AuNSs) with improved photothermal stability and conversion efficiency promotes the disintegration and transformation of selenium nanoparticles (SeNPs), thus leading to enhanced cancer cells apoptosis by producing higher hyperthermia. Moreover, the results of in vivo experiments demonstrate that the synergy between SeNPs-mediated chemotherapy and AuNSs-induced photothermal therapy not only generated a localized antitumor-immune response with excellent cancer killing effect under the presence of tumor-associated antigens, but also effectively reprogrammed the tumor associated macrophages (TAMs) from M2 to M1 phenotype with tumoricidal activity to devour distant tumors. Without a doubt, this study not only provides a potent strategy to reverse the immunosuppressive tumor microenvironment , but also offers a new insight for potential clinical application in tumor immunotherapy.
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