Dual-Targeted Self-Adjuvant Heterocyclic Lipidoid@Polyester Hybrid Nanovaccines for Boosting Cancer Immunotherapy

Tumor vaccines have demonstrated a modest response rate, primarily attributed to their inefficient delivery to dendritic cells (DCs), low cross-presentation, DC-intrinsic immunosuppressive signals, and an immunosuppressive tumor microenvironment (TME). Here, draining lymph node (DLN)-targeted and tumor-targeted nanovaccines were proposed to address these limitations, and heterocyclic lipidoid (A18) and polyester (BR647) were synthesized to achieve dual-targeted cancer immunotherapy. Meanwhile, oligo hyaluronic acid (HA) and DMG-PEG 2000 -Mannose were incorporated to prepare dual-targeted nanovaccines encapsulated with STAT3 siRNA and model antigens. The nanovaccines were designed to target the DLN and the tumor, facilitating the delivery of cargo into the cytoplasm. These dual-targeted nanovaccines improved antigen presentation and DC maturation, activated the stimulator of interferon genes (STING) pathway, enhanced the pro-apoptotic effect, and stimulated antitumor immune responses. Additionally, these dual-targeted nanovaccines overcame immunosuppressive TME, reduced immunosuppressive cells, and promoted the polarization of tumor-associated neutrophils from N2 to N1. Among the four dual-targeted nanovaccines that induced robust antitumor responses, the heterocyclic lipidoid@polyester hybrid nanovaccines (MALO@HBNS) demonstrated the most promising results. Furthermore, a combination strategy involving MALO@HBNS and an anti-PD-L1 antibody exhibited an immensely powerful anticancer role. This work introduced a dual-targeted nanovaccine platform for antitumor treatment, suggesting its potential combination with an immune checkpoint blockade as a comprehensive anticancer strategy.