Although cytotoxic treatments hold tremendous potential
in boosting
antitumor immunity, efferocytosis of tumor-associated macrophages
(TAMs) could negatively remove apoptotic tumor cells through LC3-associated
phagocytosis (LAP), resulting in inefficient tumor antigen presentation
and immunosuppressive tumor microenvironment. To address this issue,
we developed TAM-targeting nanospores (PC-CW) inspired by the predominant
tropism of Rhizopus oryzae toward macrophages. To
construct PC-CW, we disguised poly(sodium-p-styrenesulfonate)
(PSS)-coated polyethylenimine (PEI)-shRNA nanocomplexes with the cell
wall of R. oryzae conidia. LAP blockade by PC-CW
delayed the degradation of engulfed tumor debris within TAMs, which
not only enhanced antigen presentation but also initiated the domino
effect of the antitumor immune response through STING signaling and
TAM repolarization. Benefiting from this, PC-CW successfully sensitized
the immune microenvironment and amplified CD8+ T cell responses
following chemo-photothermal therapy, leading to substantial tumor
growth control and metastasis prevention in tumor-bearing mouse models.
The bioengineered nanospores represent a simple and versatile immunomodulatory
strategy targeting TAMs for robust antitumor immunotherapy.