Cooperative Self-Assembled Nanoparticle Induces Sequential Immunogenic Cell Death and Toll-Like Receptor Activation for Synergistic Chemo-immunotherapy.

Anticancer immunotherapy is hampered by poor immunogenicity and a profoundly immunosuppressive microenvironment in solid tumors and lymph nodes. Herein, sequential pH/redox-responsive nanoparticles (SRNs) are engineered to activate the immune microenvironment of tumor sites and lymph nodes. The two-modular SRNs could sequentially respond to the acidic tumor microenvironment and endosome compartments of dendritic cells (DCs) to precisely deliver doxorubicin (DOX) and imidazoquinolines (IMDQs). In the tumor microenvironment, released DOX triggers immunogenic cell death. In sentinel lymph nodes, the IMDQ nanoparticle module is dissociated in the acidic endosome compartment to specifically stimulate toll-like receptor 7/8 for DC maturation. Thus, the orchestrated nanoparticle system could enhance the infiltration of CD8α+ T cells in tumors and provoke a strong antitumor immune response toward primary and abscopal tumors in B16-OVA and CT26 tumor-bearing mice models. The cooperative self-assembled nanoparticle strategy provides a potential candidate of nanomedicine to advance the synergistic cancer chemo-immunotherapy.

A pH-Responsive Nanoparticle Library with Precise pH Tunability by Co-Polymerization with Non-Ionizable Monomers.

Precise monitoring of the subtle pH fluctuation during biological events remains a big challenge. Previously, we reported an ultra-pH-sensitive (UPS) nanoprobe library with a sharp pH response using co-polymerization of two tertiary amine-containing monomers with distinct pKa . Currently, we have generalized the UPS nanoparticle library with tunable pH transitions (pHt ) by copolymerization of a tertiary amine-containing monomer with a series of non-ionizable monomers. The pHt of nanoparticles is fine-tuned by the non-ionizable monomers with different hydrophobicity. Each non-ionizable monomer presents a constant contribution to pH tunability regardless of tertiary amine-containing monomers. Based on this strategy, we produced two libraries of nanoprobes with continuous pHt covering the entire physiological pH range (5.0-7.4) for fluorescent imaging of endosome maturation and cancers. This generalized strategy provides a powerful toolkit for biological studies and cancer theranostics.

pH-gated nanoparticles selectively regulate lysosomal function of tumour-associated macrophages for cancer immunotherapy.

Tumour-associated macrophages (TAMs), as one of the most abundant tumour-infiltrating immune cells, play a pivotal role in tumour antigen clearance and immune suppression. M2-like TAMs present a heightened lysosomal acidity and protease activity, limiting an effective antigen cross-presentation. How to selectively reprogram M2-like TAMs to reinvigorate anti-tumour immune responses is challenging. Here, we report a pH-gated nanoadjuvant (PGN) that selectively targets the lysosomes of M2-like TAMs in tumours rather than the corresponding organelles from macrophages in healthy tissues. Enabled by the PGN nanotechnology, M2-like TAMs are specifically switched to a M1-like phenotype with attenuated lysosomal acidity and cathepsin activity for improved antigen cross-presentation, thus eliciting adaptive immune response and sustained tumour regression in tumour-bearing female mice. Our findings provide insights into how to specifically regulate lysosomal function of TAMs for efficient cancer immunotherapy.