Cancer immunotherapy has emerged as a promising cancer treatment. However, its efficacy is often limited by the immunosuppressive tumor microenvironment (TME) in solid tumors. Herein, a new strategy has been presented by using bioorthogonal chemistry to reprogram TME. We designed a bifunctional mannose (Man) vector decorated palladium bioorthogonal nanozyme for in-situ synthesis of histone deacetylase inhibitor (HDACi) vorinostat (FDA approved) with the ability to remodel tumor microenvironment. To the best of our knowledge, this is the first report to use a bioorthogonal nanozyme for cancer immunotherapy. In particular, the nanozyme could preferentially accumulate in M2 macrophages (termed M2Φ) to achieve local M2 re-education, which effectively avoided unnecessary inflammation in normal tissues. Moreover, vorinostat-induced TME reprogramming was synergistic with peroxidase-like activity of the nanozyme, and achieved enhanced tumor synergistic immunotherapy. In colon cancer (CT26)-tumor-bearing BALB/c mice, the nanozyme demonstrated macrophages polarization targeting M2Φ and activation of innate immune system, resulting in significantly enhanced tumor growth inhibition. Our work not only provides a new effective way to reprogram TME in vivo, but also shed light on the design of novel bioorthogonal nanozymes for cancer immunotherapy.

Tumor associated macrophages reprogrammed by targeted bifunctional bioorthogonal nanozymes for enhanced tumor immunotherapy
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DOI: 10.1016/j.mattod.2022.01.024