An Immunotherapy Strategy Targeting Programmed Cell Death Ligand 1 and CD73 with Macrophage-Derived Mimetic Nanovesicles to Treat Bladder Cancer

Abstract BackgroundThe tumor microenvironment in bladder cancer exerts an inhibitory effect on immune effector cells. Thus, removing this inhibitory effect could help improve the efficacy of immune checkpoint inhibitors, and combination immunotherapy is a promising strategy for increasing the proportion of patients with bladder cancer who benefit from immune checkpoint inhibitors. However, it is difficult to effectively and simultaneously deliver multiple drugs to the tumor tissue. In this study, we describe the design and in vivo validation of macrophage-derived exosome-mimetic nanovesicles (EMVs) as a nanoplatform for coloading and targeted delivery of a CD73 inhibitor (AB680) and monoclonal antibodies targeting programmed cell death ligand 1 (aPDL1). ResultsOur results indicated that these nanocomplexes (AB680@EMVs-aPDL1) were highly stable, provided adequate biosafety in vivo, and exhibited enhanced targeting in a mouse model of bladder cancer. Moreover, the CD73 inhibitor reduced extracellular adenosine production, and the combination therapy significantly promoted activation of cytotoxic T lymphocytes, resulting in suppression of tumor growth in vivo. ConclusionsTherefore, using EMVs to deliver a combination of aPDL1 and a CD73 inhibitor may be an effective combined immunotherapy strategy for treating bladder cancer.