Lu, J., et al. Lysosomal disruption elicits immunogenic cell death: A saponin-nanoaluminum adjuvant for enhanced cancer immunotherapy
Acta Biomater, 2026 Aug, 220:276-291. PMID: 42468600
This paper introduces a novel saponin-based nanoadjuvant, QS-NanoAlum, that leverages lysosomal disruption to induce immunogenic cell death (ICD) in tumors. Unlike traditional adjuvants that primarily enhance immune responses without direct tumor cell killing, QS-NanoAlum physically disrupts lysosomal membranes within tumor cells, causing their self-lysis and subsequent release of tumor antigens, thus serving as both a therapeutic and immunostimulatory agent. The innovative aspect lies in the self-lysis mechanism triggered by lysosomal membrane permeabilization, circumventing the need for specific molecular targets, which is significant given tumor heterogeneity and resistance. The study demonstrates that QS-21, a well-established saponin adjuvant, when loaded onto an aluminum nano-carrier, effectively induces ICD, captures tumor antigens, and elicits potent systemic anti-tumor immunity in vivo. This approach advances the scope of saponin adjuvants from mere immune boosters to active tumor disruptors, presenting a promising new paradigm in cancer immunotherapy with potential to overcome limitations of conventional treatments.
The immunological results demonstrate that treatment with QS-NanoAlum significantly enhances immune responses within the tumor microenvironment and systemically. Specifically, immunohistochemical analysis revealed increased infiltration of immune cells such as CD4+, CD8+, and CD11c+ cells into tumor tissues, alongside elevated expression of damage-associated molecular patterns (DAMPs) like CRT and HMGB-1, indicative of immunogenic cell death (ICD) induction. Additionally, splenocyte analysis showed a marked increase in systemic CD8+ T cell populations, suggesting activation of cytotoxic T lymphocytes. Serum cytokine measurements further confirmed an elevated pro-inflammatory environment, with increased levels of cytokines such as TNF-α, IFN-γ, IL-1β, and IL-6, reflecting systemic immune activation.
The study concludes that QS-NanoAlum serves as a potent, biocompatible nanoparticle-based immunoadjuvant capable of inducing lysosomal disruption and immunogenic cell death in tumor cells. Its dual function of facilitating antigen release and promoting dendritic cell maturation enhances systemic anti-tumor immunity, resulting in significant suppression of primary and metastatic tumors. These findings support the potential of QS-NanoAlum as a promising platform for cancer immunotherapy, combining effective tumor destruction with immune activation while maintaining a favorable safety profile.
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