Vitalizing Immortal Nanodendritic Cells Functionalized with Immune-checkpoint Inhibitors for Tumor-localized Immunotherapy

Recently, cancer immunotherapies combining nanotechnology have been highlighted due to the high impact of substantial clinical potential in various types of solid cancers. Especially, nanoparticle (NP)-based technology is a well-known and powerful tool for manipulating functionalities and ensuring in vivo stability, making it suitable for personalized cancer therapy. As an advanced form of immunotherapy using nanotechnology, the combination of cell-based therapy and NP technology has been emerging, for example, introducing cellular membranes or extracellular vesicles onto the NPs. This delivers the entire information of the cell membrane to the NP surface without damage and could be regarded as a useful technology for cell mimicking.<br/>Meanwhile, dendritic cells (DCs) have been recognized as promising targets for immunotherapy due to their crucial role in T cell activation. However, administrated DCs in patients showed poor lifetime in vivo, which resulted in limited antigen-presenting capabilities in clinical trials. Furthermore, the storage and recovery of DCs for further usage are also challenging to retain DC survival rate and functionalities. To overcome these limitations, we have developed immortalized nanodendritic cells for cancer immunotherapy by combining DC therapy with cell-mimicking nanotechnology.<br/>By utilizing immortalized DCs with extended lifetimes, we believe that continuous antigen presentation and T cell activation can be achieved in vivo. Our idea to prepare immortalized DC was inspired by cell membrane clocking technology which was first developed by L. Zhang et al. Using this technique, the whole DC membrane could be successfully decorated onto gold nanoparticle (Au NP), which is named artificial nanoDCs (anDCs). We optimized the manufacturing process of anDCs both biologically and thermodynamically to enhance their therapeutic efficacy. The optimized anDCs demonstrated thermodynamic stability and retained their functional abilities even after long-term storage of up to 30 days. We also confirmed the strong tumor regression effect of anDCs due to the fact that the nanosized DC can accumulate in the tumor site or lymph node without degradation, resulting in enhanced T cell activation in vivo.<br/>Finally, to boost the T cell activation effect, the anDC was engineered with immune-boosting agents, immune-checkpoint inhibitors (ICIs). By direct engineering anDC with anti-CTLA-4 (aCTLA-4), we could obtain potent anDCs to induce T cell effector function efficiently. In our research, we validated the efficacy of aCTLA-4-conjugated anDCs in three different tumor models (MC38, CT26, and TC-1). Surprisingly, aCTLA-4-conjugated anDCs exhibited substantial tumor regression compared to the control group, as confirmed by in vivo immune analysis, which showed augmented tumor-infiltrating lymphocytes.<br/>In summary, our objective was to develop optimized therapeutic drugs for cancer immunotherapy that can mimic the behavior of DCs. We successfully created a DC-mimicking therapeutic anticancer drug that can continuously and strongly activate tumor-specific T cells, thereby resulting in dramatic tumor regression. Furthermore, by conjugating various immune-boosting agents to anDC, we strongly anticipate that our material could be manufactured as desired and provided for patient-specific needs.